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ISSN 0003 1216

J O U R N A L

OF THE

AMERICAN SOCIETY

OF

SUGAR BEET T E C H N O L O G I S T S

VOL. 20, No. 3 JULY 1979

EXECUTIVE COMMITTEE

President M A . Woods Union Sugar Division

Santa Maria. California

Vi<e President Stewart Bass American Crystal Sugar Co,

Moorhead. Minnesota

Secretary Treasurer James H. Fischer Beet Sugar Development Foundation

Fort Collins. Colorado

Immediate Past President Glen W. Yeager I lolly Sugar Corporation

Colorado Springs. Colorado

BOARD OF DIRECTORS

Pacific Coast Region: John M. Kendrick

Intermountain Region: A. Kent Xielson

F.astern Rockv Mountain

Region: D. D. Dickenson

North Central Region: E.L..Swift

Great Lakes Region: Richard Zielke

Canadia: John W. Hall

Processing at Large: Stanley F. Bichsel

Agriculture at Large: John T. Alexander

ISSN 0003-1216

J O U R N A L

of the

American Society of Sugar

Beet Technologists

Volume 20 Number 3 July 1979

American Society of Sugar Beet Technologists

Office of the Secretary

P.O. Box 1546

Fort Collins. Colorado 80522

Made in the United States ot America

TABLE OF CONTENTS

Title Author Page

A study of sugar drying and conditioning. .. Souly Farag 207

Residual soil nitrogen and phosphorus in D. G. Westfall some sugarbeet fields W. J. Eitzman in Montana and Wyo- D. R. Rademacher ming R. G. Vergara 217

Bibliography: methods of sucrose analysis. . . .Douglas W. Lowman 233

Separation and analysis of some sugars by using thin layer chromatography Souly Farag 251

Effect of chemicals on sucrose in sugar- W. R. Akeson beets during stor- Y. M. Yun age E. F. Sullivan 255

Effect of injury on respiration rates R. E. Wyse of sugarbeet roots C. L. Peterson 269

Remedying inadequate crystallizer capacity R. A. McGinnis 281

The effect of soil residues of atra- R. L. Zimdahl zine on sugarbeets s. M. Gwynn (Beta vulgaris L . ) . . . . K. Z. Haufler 297

The effect of root dehydration on the storage performance of a sugarbeet genotype resistant to W. M. Bugbee storage rot D. F. Cole 307

A Study of Sugar Drying and Conditioning

SOULY FARAG

Received for publication August 15, 1977

ABSTRACT

A laboratory investigation of the mechanism of sugar dry

ing was conducted. The effects of drying time, air temper

ature, and agglomerates on drying rate and the final mois

ture content of sugar crystals were examined. Because of

the complicated nature of this study on a factory scale,

a bench model granulator was constructed.

The study indicated that the drying temperature has consid

erable effect on the quality of the finished product. High

temperature drying tends to encourage the formation of

small sugar particles which can in part contribute to the

dust problem.

INTRODUCTION

In the sugar industry, it is necessary to store a signifi

cant portion of the production for a considerable length of

time. Caking and dust formation are usually encountered

during sugar handling and storage. The final product

should, however, reach the consumer in first class condi-(2)

tion. Krautmann claimed that most of the unfavorable

phenomena such as caking and dust formation result from

the supersaturated film on the crystal surface and are

caused by conditions encountered during the drying process.

Powers (4) indicated that the major cause of dust formation

is the rapid drying of the thin films of syrup left on

sugar after spinning. Accordingly, drying in the granu

lator may be considered as a continuation of the crystal

lization process. Others demonstrated that wet sugar

*Sr. Research Chemist, U & I, Incorporated, Moses Lake, Washington 9 8 837.

208 JOURNAL OF THE A.S.S.B.T.

samples washed with alcohol prior to drying dried with a

brilliant shine, a negligible amount of dust, and very

little tendency toward caking.

This investigation was undertaken in order to determine the

effects of various drying conditions on the physical char

acteristics of sugar crystals.

MATERIALS AND METHODS

Equipment: A bench batch dryer (granulator) with an approx-

imate capacity of 12 quarts per hour was constructed at our

laboratory. It consisted of a cylinder 18" long and 12"

in diameter, with eight evenly spaced flights inside to

give a more efficient agitation of the sugar. The granu

lator was supplied with a small fan and heating unit to

provide a stream of forced hot air, and was rotated at a

constant speed of ten revolutions per minute. The granu

lator was capable of drying a two liter sample of sugar to

.05% moisture content in approximately the same time as

that required by the factory granulators.

A conditioning bin model was also constructed. It con

sisted of an 18" long by 5" diameter glass chromatogranh

tube with a fritted glass disc in the bottom. Air was

blown up through the disc and distributed through a layer

of sugar placed over it. The air supply was laboratory

compressed air that had passed through a silica gel dryer

and a rotameter to measure the volume of air used.

Moisture was determined on the samples by a standard method

for the determination of moisture in sugar. Samples were

dried in glass-stoppered weighing bottles for a period of

three hours in a 105°C oven, then cooled and reweighed to

determine weight loss. Dust levels were determined by us

ing the method developed at the U and I Research Labora-

tory. ( 1 )

Procedure: A two-liter sample of wet sugar was found to be

VOL. 20 NO. 3 JULY 1979 209 the optimum amount for the operation of the bench granula-

tor. Prior to drying a sample, the granulator was preheat

ed to the desired temperature for a period of 10 to 15

minutes, then the sample of wet sugar was added. Drying

temperatures were varied from 25° to 145°C. The granulator

was started with samples collected at pre-determined inter-

vals in bottles which were stoppered and allowed to cool.

Approximately 10 grams of the sample was taken, quickly

and accurately weighed, then dried in an oven for three

hours at 105°C.

The sample was then cooled in a dessicator, reweighed, and

the percent moisture calculated. The dried sugar was con

ditioned and examined under the microscope. Finally, the

sample was tumbled in a plastic bottle for 30 minutes in

order to simulate the effect of physical movement, and

dust levels determined.

Further tests were conducted in order to examine the drying

pattern of sugar crystals as compared to the drying char

acteristics of both wet sand and sodium chloride, and

additional tests compared the drying rate of conglomerate

sugar to that of clean, uniform grain.

RESULTS AND DISCUSSION

The average results for varying air temperatures (25, 70,

100 and 145°C) are illustrated in Figure 1. It should be

noted that in all cases the initial moisture content was

considered to be unity, and all moisture contents were

adjusted accordingly.

From these curves, it can be seen that sugar drying is not

a smooth, continuous process. Each curve can be divided

into a warming up period followed by a constant rate period

which appears on the graph as a straight line. The third

period of drying is typified by a continuously changing

rate until the entire surface is supersaturated. This marks

the start of a portion of the drying cycle in which the rate

210 J O U R N A L OF T H E A.S.S.B.T.

Figure 1. Sugar drying at various temperatures.

of internal moisture movement and crystallization from the

syrup controls the drying rate. (3)

Figure 2. Air temperature versus drying time (constant time curves) - Moisture indicated as percent.

VOL. 20 NO. S JULY 1979 211 Figure 2 shows the length of time required to reach percent

moistures from 0.8 to 0.04 at various air temperatures.

Note, for example, that with air at 140°C, it takes 1.25

minutes to dry sugar to 0.06% moisture. If the same sugar

were dried with air at 100°C, it requires only two minutes.

A drop of 40°C in air temperature lengthens the drying time

to the .06% moisture level by only three-quarters of a

minute. On the other hand, there is a much larger differ

ence in the time required to reduce the moisture level from

.06 to .04% at temperatures below 100°C. At these moisture

levels, the low temperatures do not appear to provide the

driving force required to force the moisture out of the

saturated sugar solution surrounding the crystals.

Figure 3. Air temperature versus % moisture (constant time curves) - Time indicated in seconds.

Figure 3 includes constant-time curves which illustrate

the relationship of moisture to temperature; both high tem

perature and long drying time are required in order to

effect moisture reduction below the 0.1 level.

Figure 4 includes the drying curves for equal volumes of

sugar, sand, and sodium chloride dried at 100°C. In the

case of drying sand, the phenomenon illustrated is merely

212 JOURNAL OFTHE A.S.S.B.T.

Figure 4. Comparison between drying curves, Sugar-sand-salt.

the evaporation of water from the surface. In the case of

sugar, the wet sugar loses moisture first by evaporation

from a syrup film on the surface of the crystal down to

a moisture content of approximately .05%, followed in turn

by a period of evaporation of a supersaturated surface which

is gradually increasing in saturation until such a point

that crystallization starts to take place. It is at this

point that, in theory, the dust is formed. Sodium chloride

is similar to sugar in that it is a soluble solid. It

does not, however, form an appreciable glaze or surface

layer upon drying as sugar does. This layer seems to

cause an increase in the drying time of sugar crystals.

It should be pointed out that both sand and sodium chloride

have higher specific gravity and higher specific heat than

sugar.

Sample 1 was a strike of sugar that had a large percentage

of conglomerates, while Sample 2 had a very clean, uniform

grain. As can be seen from the table, Sample 1 had a

higher initial moisture content than did Sample 2. - the

latter had half the moisture content of Sample 1 after

they both had been dried for a 10-minute period. This

is due almost entirely to the fact that a conglomerate

sugar has more syrup trapped on the surface, than does a

well formed crystal. On a number of samples tested, there

was a large variation in the moisture content of the sugar

being introduced to the granulator. It has been shown

that the initial moisture content has a very important

bearing on the efficiency of the granulator operation,

A further study of dust formation at various air tempera

tures was as follows:

Wet sugar samples were taken from the spinners, then dried

for ten minutes in the laboratory bench granulator at

70, 100, and 145°C, respectively. The samples were further

treated for four hours in a conditioning bin model using

dry air in an attempt to remove all moisture present in

sugar in excess of the equilibrium quantity. Samples were


then tumbled in plastic bottles for 30 minutes. Percen-

tages of dust were determined at 0.043, 0.058, and 0.083,

respectively.

Microscopic examination of different samples indicated that

crystals dried at higher temperature (145°C) were clear and

sparkling as they came from the granulator. After condi-

tioning, the sugar became dull and the slightest movement

could produce very fine dust. On the other hand, sugar

dried at lower temperature does not change appreciably

in appearance after it has been conditioned. In general,

there was a tendency for sugars dried at higher tempera-

ture to form dust more readily than sugars dried at lower

temperatures. Figures 5 and 6 illustrate the effect of dry-

Figure 5. Sugar sample Figure 6. Sugar sample dried at 100°C. dried at 145°C.

ing temperature on dust formation. It can be seen that

the coating surrounding the crystals dried at 145°C looks

almost amorphous. The submicroscopic crystals covering

the mother crystal can be seen easily through the micro-

scope at a high magnification (325x). It should be point-

ed out, however, that samples dried at high temperature

(120-145°C) had less caking and required longer time for

setting-up to take place.

VOL. 20 NO. 3 JULY 1979 215

Figure 7. Sugar crystal dried at 145°C at 325x.

It is important to emphasize that the drying rate and the

final moisture content of sugar are also influenced by other

factors besides time, temperature, and conglomeration.

These factors include particle size, initial moisture con-

tent, and the humidity of the surrounding air.

CONCLUSION

This study indicates that the drying temperature has con-

siderable effect on the nature of the finished sugar. High

temperature drying tends to encourage the formation of

small sugar particles loosely bound to the surface of the

sugar crystal, giving it a dull, opaque appearance. Dur-

ing handling these particles are rubbed off quite easily

and contribute at least in part to the dust problem.

Furthermore, any means of producing a wet sugar product

at a reduced and uniform moisture content would be of great

advantage. In this light, it can be seen that the centri-

fugals act as separators and physically remove the moisture.

This is a relatively simple process which requires a rela-

tively small amount of energy. On the other hand, granu-

lators remove the water by a phase change or evaporation


Which, from an engineering standpoint, requires a much

greater amount of energy.

LITERATURE CITED

(1) Farag, S. A., L. W. Norman, and C. L. Schmalz. 1971. Some physical characteristics of sugar crystals affecting dust formation. Sugar Beet Technol. 16: 448-456.

(2) Krautmann, Hans. 19 60. Preparing refined sugar for silo storage. Sugay y Azucar 55: 50-51.

(3) Perry, John H. 1963. Chemical Engineer's Hand-book, pp. 15-35.

(4) Powers, H.E.C. 1960. Sugar Crystallization in thin films. International Sugar Journal 62: 307-312.

Residual Soil Nitrogen and Phosphorus in some Sugarbeet Fields in Montana and Wyoming

D. G. WESTFALL, W. J. EITZMAN,

D. R . R A D E M A C H E R A N D R. G . V E R G A R A *

Received for publication December 5, 1977

INTRODUCTION

Proper management of soil fertility in sugarbeet (Beta vul-

garis L.) production is of economic importance, particular-

ly with nitrogen (N) where the proper control of N availa

bility is a critical compromise between supplying enough

to produce optimum yields and yet limiting availability to

produce sugarbeets of high sugar content and purity (1, 3,

4, 5, 7, 8, 9, 10, 11, 12, 13, 15, 20, 25, 28, 29, 30).

Nitrogen fertility requirement can best be determined with

deep soil sampling and analysis of these samples for re-

sidual NO -N (8, 15, 16, 18, 24, 25). Consequently, the

importance of a deep soil sampling program to the economics

of sugarbeet production is indisputable.

Phosphorus (P) is the second most important fertilizer nut-

rient that is needed for sugarbeet production. Growers

and soil scientists recognize that soil testing is the only

reliable method to determine P fertilizer requirements.

Several investigators (4, 22, 26) have summarized the re-

search results on P requirements of sugarbeets. A detri-

mental effect on sugarbeet yield from applying P fertilizer

to soils that test high in residual P has been suggested

(6, 14), although conclusive evidence has not been reported.

*The authors are respectively Senior Plant Nutritionist, Great Western Sugar Co., Agricultural Research Center, Longmont, CO 80501; Former Manager, Agricultural Research, Montana-Wyoming (Presently Agriculturalist, Billings, M T ) ; Manager, Agricultural Research, Oregon; and Agriculturalist, Lovell, Wyoming. The senior author is presently an Associate Professor, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523.


Our results from a number P rate experiments, however, have

nόt evealed a detrimental effect of excessive P fertility

rates on sugarbeet yield or quality.

It has been suggested by Skogley (27) that sugarbeets may

require potassium (K) fertilizer on some soils in Montana.

This opinion is not shared by the authors. Secondary and

micronutrient difficiencies are not known to exist in sug-

arbeets in the area studied; consequently, the only fer-

tilizer nutrients required for maximum sugar production

are N and P.

Several hundred fields have been soil sampled since 1974

in the Great Western Sugar Co. factory districts of Bil-

lings, Montana and Lovell, Wyoming for fertilizer recom-

mendations for sugarbeet growers. This is the first ex-

tensive deep soil sampling data to be collected in these

two areas. The results are summarized in this publication

with the following objectives: 1) to identify the residual

soil N and P levels that commonly occur; 2) to determine

the residual soil N profile distribution; and 3) to evalu-

ate the effect of previous cropping history on residual soil

N and P leveIs.


Soil samples were collected at 1-foot increments to a depth

of 3 feet in the Lovell, Wyoming district (Big Horn Basin)

and to a depth of 3-6 feet in the Billins, Montana district

(Middle Yellowstone River Valley). A gravel layer at ap-

proximately 3 feet in the Big Horn Basin restricts sampl-

ing and limits root development below this depth. All data

from Montana were adjusted to a 4-foot depth since this is

the maximum recommended sampling depth (2) and is generally

considered to be the effective rooting depth of sugarbeets

in these soils. The following number of fields were sampled

in the preceeding fall or spring for the various crop years:

Wyoming, 1974 - 56 fields and 1975 - 185 fields, total - 241

VOL. 20 NO. 3 JULY 1979 219

f i e l d s ; M o n t a n a , 1974 - 36 f i e l d s , 1975 - 84 f i e l d s , 1976

- 5 1 fields and 1977 - 135 f i e l d s , total - 306 f i e l d s .

The 0-1 foot s a m p l e was a n a l y z e d for a v a i l a b l e P w i t h the

s o d i u m b i c a r b o n a t e m e t h o d (21) and organic m a t t e r (O.M.)

by the wet — o x i d a t i o n m e t h o d . All foot i n c r e m e n t s w e r e an-

alyzed for N0 3 - N u s i n g the O r i o n s p e c i f i c ion e l e c t r o d e

s y s t e m by the f o l l o w i n g p r o c e d u r e : A 50 g soil s a m p l e w a s

e x t r a c t e d with 180 m l d i s t i l l e d w a t e r ; the s u p e r n a t e w a s

c e n t r i f u g e d and d e c a n t e d after w h i c h 0.1m s o d i u m c i t r a t e

was added (1:9 c i t r a t e to e x t r a c t ratio) to e l i m i n a t e e l e c

trode i n t e r f e r e n c e s due to v a r y i n g ionic s t r e n g t h s b e t w e e n

e x t r a c t s ( 2 3 ) . The r e s u l t s are r e p o r t e d in lb N03 - N / A .

R E S U L T S AND D I S C U S S I O N

R e s i d u a l N i t r a t e — N i t r o g e n

The r e s i d u a l NO -N l e v e l s in M o n t a n a and W y o m i n g in 25 l b / A

i n c r e m e n t s are s h o w n in F i g u r e s 1 and 2. In M o n t a n a , the

m a j o r i t y of the fields had r e s i d u a l N 0 3 - N l e v e l s r a n g i n g

from 2 6 - 5 0 (30%) and 5 1 - 7 5 lb/A (31%) with less than 1%

h a v i n g r e s i d u a l l e v e l s less than 26 lb/A. A d i f f e r e n t dis-

t r i b u t i o n p a t t e r n o c c u r r e d in W y o m i n g . The m a j o r i t y of the

f i e l d s had r e s i d u a l NO -N l e v e l s r a n g i n g from 0-25 (30%)

and 2 6 - 5 0 lb/A ( 4 2 % ) . The 0-25 lb/A of r e s i d u a l N 0 3 - N

range of 3 0 % o c c u r r e n c e in W y o m i n g is c o n t r a s t e d to less

than a 1% o c c u r r e n c e in M o n t a n a . T w e n t y - o n e p e r c e n t of

the fields in M o n t a n a had r e s i d u a l N0 3 - N levels a b o v e 100

lb/A w h i l e in W y o m i n g only 8% of the fields e x c e e d e d this

l e v e l . L u d w i c k , S a l t a n p o u r , and Reuss (19) r e p o r t e d the

d i s t r i b u t i o n of r e s i d u a l N O 3 - N levels of soil s a m p l e s test-

ed by the C o l o r a d o State U n i v e r s i t y Soil T e s t i n g L a b o r a t o r y .

T h e s e f i g u r e s p e r t a i n e d to the e n t i r e state and not spe-

c i f i c a l l y to s u g a r b e e t f i e l d s a l t h o u g h the vast m a j o r i t y

of s a m p l e s u n d o u b t e d l y came from a r e a s w h e r e s u g a r b e e t s

are g r o w n in r o t a t i o n with other c r o p s . They r e p o r t e d that

5 0 % of the C o l o r a d o f i e l d s c o n t a i n e d less than 3.6 lbs N / A

and 2 2 % c o n t a i n e d from 36 to 72 lbs N/A. The d i s t r i b u t i o n

p a t t e r n in M o n t a n a soils is q u i t e d i f f e r e n t in that less


RESIDUAL N O 3 - N ( lbs . A )

Figure 2. The residual soil NO3 -N levels of sugarbeet fields in Wyoming.

VOL. 20 NO. 3 JULY 1979 221

than 1% of the fields contained less than 25 lb N/A. The

Wyoming patterns are more similar to those reported for

Colorado.

The differences in residual N0--N levels in Montana and

Wyoming are expected because the soils of the Big Horn Ba-

sin in Wyoming are generally light textured, shallow soils

that are subject to leaching if excessive irrigation water

is applied. The annual precipitation is approximately 7

inches; consequently, this does not result in leaching.

In the Middle Yellowstone River Valley of Montana, the

soils are generally heavier textured and deeper. Annual

precipitation is about 14 inches. In general, little NO3-N

leaching from rainfall is expected. The exception to this

may be after heavy down pours or during snow melt when

water accumulates in low areas of fields.

The average distribution patterns of the residual N03-N

within the profiles of the two areas of study are shown in

Figures 3 and 4 . In Montana, 38% of the NO -N was present

in the surface foot with 23%, 20% and 19% in the second,

third and fourth foot increments, respectively. In the

shallower soil profiles of Wyoming, the decrease in resid-

ual NO3-N with depth is very rapid. About 62% of the re-

sidual NO3-N was found in the surface foot with 22% and

18% occurring in the second and third foot increment, re-

spectively. In some Colorado soils, Reuss and Rao (24)

reported that 60% of the residual N03-N was present in the

surface foot of their 4-foot profile. In a second study

Ludwick, Reuss, and Giles (18) found about 50% of the re-

sidual N O - N occurred in the surface foot. The level of

N O - N in the surface foot in the average Montana soil pro-

file is considerably less than that reported by the Colo-

rado researchers.

The wide variation in residual N03-N levels in fields in

the areas studied clearly points out that an "average"

fertilizer reco mm endation can not be made with the expecta-

222 JOURNAL OFTHE A.S.S.B.T. DISTRIBUTION OF RESIDUAL

Figure 3. The average profile distribution of residual NO3-N in sugarbeet fields in Montana.

F i g u r e 4 . The average profile distribution of residual NO3 -N in sugarbeet fields in Wyoming.

VOL. 20 NO. 3 JULY 1979 223

tion of achieving the optimum compromise between yield and

quality. An optimum rate can be achieved only through soil

testing of each field and tailoring the N recommendation to

take into account the specific residual N03-N level present

in that field .

Organic Matter

The distribution of O.M. content of the fields in the two

areas are presented in Figures 5 and 6 . The most frequent

ly observed O.M. range in both areas was 1.1-1.5% with a

43 and 66% distribution in Montana and Wyoming, respective

ly. The range of O.M. content in Wyoming is narrower than

in Montana; only 20% of the Wyoming fields had less than

1% O.M. and only 1% had greater than 2.0% O.M. These dis

tributions are contrasted to 27% less than 1.0% O.M. and

7% greater than 2.0% O.M. in Montana.

Residual Phosphorus

The P distributions are shown in Figures 7 and 8. In both

areas about 10% of the fields tested very low in P. Using

the new P fertilizer recommendations of the Great Western

Sugar Co. and Colorado State University, the fertilizer

recommendation would be 100 lb P205/A for a "very low" P

test level. Forty-four and 32% of the fields tested "low"

in P with a 50 lb P 0 /A fertilizer recommendation and 29

and 36% tested "medium" with a 30 lb P205 /A recommendation

for Montana and Wyoming, respectively. Soil test levels

above 23 ppm P do not need P fertilization; in Montana this

constituted 17% of the fields and Wyoming 24%. Most fields

received P fertilizer each year and excessive P fertilizer

rates are probably applied in these areas as is the situa

tion in the rest of the G. W. production area. Neverthe

less, many of the fields do need P fertilizer. The wide

range in percent P distribution of fields from these two

areas further points to the need for soil testing. This is

the only reliable method of determining the proper amount

of P fertilizer to apply.

i


F i g u r e 5. The soil o r g a n i c m a t t e r c o n t e n t of s u g a r b e e t fields in M o n t a n a .

F i g u r e 6. The soil o r g a n i c m a t t e r c o n t e n t of s u g a r b e e t fields in W y o m i n g .

VOL. 20 NO. 3 JULY 1979 225

RESIDUAL P0 4 - P (ppm )

F i g u r e 7. The r e s i d u a l soil P O 4 - P levels of s u g a r b e e t f i e l d s in M o n t a n a .

F i g u r e 8. The r e s i d u a l soil P O 4 - P l e v e l s of s u g a r b e e t fields in W y o m i n g .

226 JOURNAL OF THE A.S.S.B.T. Previous Cropping History

The previous cropping history had an appreciable influence

on the residual and P levels found in fields in Wyo-

ming but not in Montana (Table 1 ) . In Wyoming, when the

previous crop was sugarbeets, the average residual soil

N O - N level was very low (25 lb/A) and the P level was in

the "medium" soil test range (18.2 ppm). The highest

level was found when the previous crop was malting barley.

The soil test P level was also in the "medium" range. Pre

vious crops of beans, small grains, and corn had N O - N lev

els ranging from 4 5 to 6 6 lb/A and P levels of 12.1 to 14.7

ppm. In Montana, the and P levels were very narrow

and were not appreciably different. The reason for the dif

ferences in residual NO3-N levels in Wyoming may possibly

be attributed to mineralization that occurs between crop

removal and sampling as well as fertilizer carry over.

Corn, malting barley and small grains are harvested several

weeks earlier than sugarbeets. This may result in an ac

cumulation of from mineralization while, no crop is

growning on the soil.

Table 1. Relationship between previous crop and residual N O 3 N and PO -P levels in fields to be planted to sugarbeets (1975).

Previous Crop

Sugarbeets

Beans

Sma11 Grains

Corn

Malting Barley

VOL. 20 NO. 3 JULY 1979 227 Soil Test Variations Between Areas

To further identify the fertility relationships in these

two regions, the soil test information from various geo

graphic areas was summarized. The areas were determined by

the proximity to receiving stations in what is considered

to be "similar production areas." The residual P levels

in Montana ranged from 11.5 ppm in the Pompeys Pillar-Worden

area to 22.8 ppm in Laurel-Park City area (Table 2 ) . The

Wyoming range was much narrower: a low of 12.9 ppm in Deaver

to a high of 19.4 ppm in the Willwood area. The average

residual P level in Wyoming is higher than in Montana. The

reason for this is not fully understood since Montana soils

are heavier textured and higher in O.M. This difference is

likely due to different fertility practices in the two areas

but could also be related to geologic factors.

The 0. M. content ranged very little in both Montana and

Wyoming with the exception of the Hysham area. The O.M.

content of this area averaged 2.86%; 1.25% higher than any

other area.

The average residual NO -N level in Montana was about twice

as high as in Wyoming. Previous work (D. G. Westfall, un

published) has shown that there is a very high correlation

between residual NO3-N levels in the spring and sugar con

tent at harvest. The Lovell factory generally has the high

est company average sugar content which could be expected

comparing residual NO3-N values between areas. The resid

ual NO -N (and total N) level in Laurel-Park City area ave

raged 113 lb/A, highest for Montana areas; the Hardin area

was lowest (63 lb/A). It is interesting to note that the

Laurel-Park City area also had the highest P level. These

high levels indicate that growers in this area are using

higher N and P fertilizer rates than in other areas. This

practice would not be limited to sugarbeets, but also ap-

plied to other crops in the rotation. The residual NO3-N

variation between areas was much smaller in Wyoming, with

the maximum being 54 lb/A and the minimum 33 lb/A. The

Table 2. The phosphorus, organic matter and residual nitrogen levels of sugarbeet fields in various production areas of Montana and Wyoming.

VOL. 20 NO. 3 JULY 1979 229

e x i s t e n c e of a g r a v e l layer in the p r o f i l e at a b o u t three

feet and the o c c u r r e n c e of l e a c h i n g d u r i n g i r r i g a t i o n is

thought to be the r e a s o n for the lower a v e r a g e l e v e l of

r e s i d u a l N 0 3 - N as w e l l as the r e l a t i v e u n i f o r m i t y b e t w e e n

a r e a s .

S U M M A R Y

The r e s i d u a l N O 3 - N , P, and O.M. c o n t e n t s of f i e l d s to be

p l a n t e d to s u g a r b e e t s w e r e d e t e r m i n e d in the G r e a t W e s t e r n

Sugar Company's p r o d u c t i o n areas of M o n t a n a and W y o m i n g .

The p e r c e n t o c c u r r e n c e of fields w i t h i n v a r i o u s r a n g e s w a s

d e t e r m i n e d . The r e s u l t s show that a w i d e v a r i a t i o n in

r e s i d u a l NO 3-N and P l e v e l s occur in these p r o d u c t i o n a r e a s .

This p o i n t s out the i m p o r t a n c e of soil testing to d e t e r m i n e

the m o s t e c o n o m i c a l f e r t i l i z e r r e c o m m e n d a t i o n . N o g e n e r a l

f e r t i l i z e r r e c o m m e n d a t i o n can be m a d e . This is e s p e c i a l l y

true i n M o n t a n a w h e r e r e s i d u a l N O 3 - N levels w e r e g e n e r a l l y

h i g h e r and m o r e v a r i a b l e than in W y o m i n g . Based on the

a v e r a g e total r e s i d u a l N a v a i l a b l e in the M o n t a n a s o i l s ,

the a v e r a g e N f e r t i l i z e r r e c o m m e n d a t i o n w o u l d be 87 l b / A .

This w o u l d result in p r o p e r N f e r t i l i z a t i o n of a b o u t 1 8 %

of the f i e l d s , under f e r t i l i z a t i o n of 6 2 % and over f e r

t i l i z a t i o n of 2 0 % . N e e d l e s s to s a y , a v e r a g e s are not a p

p l i c a b l e w h e n m a k i n g a f e r t i l i z e r r e c o m m e n d a t i o n for a

s p e c i f i c f i e l d . Deep soil testing is the only i n t e l l i g e n t

m e t h o d t o d e t e r m i n e a c c u r a t e f e r t i l i z e r r e c o m m e n d a t i o n s

that w i l l i n s u r e o p t i m u m e c o n o m i c r e t u r n .


LITERATURE CITED

(1) Adams, S. N. 1962. The response of sugar beet to fertilizer and the effect of farmyard manure. J. Agric. Sci., Camb. 58:219-26.

(2) Anonymous, 1974. Fertilizer Guide, Sugarbeets - Ir-rigated. Montana State University Extension Ser-vice publication AG55.61:60.

(3) Boyd, D. A., P. B. H. Tinker, A. P. Draycott and P. J. Last 1970. Nitrogen requirement of sugar beet grown on mineral soils. J. Agric. Sci., Camb. 74:37-46.

(4) Draycott, A. P. 1972. Sugarbeet nutrition, 250 p. John Wiley & Sons, New York.

(5) Draycott, A. P. and G. W. Cooke 1966. The effect of potassium fertilizer on quality of sugar beet. Potass. Symp. 1966, 131-5.

(6) Draycott, A. P., M. J. Durrant, and D. A. Boyd. 1971. The relationship between soil phosphorus and response by sugarbeet to phosphate fertilizer on mineral soils. J. Agric. Sci., Cam. 77:117-121.

(7) Follett, R. H., W. R. Schmehl, LeRoy Powers, and Merle G. Payne. 1964. Effect of genetic popula-tion and soil fertility level on the chemical composition of sugar beet tops. Colo. Agr. Exp. Sta. Tech. Bull. 79.

(8) Giles, J. F. 1974. Prediction of nitrogen status of sugar beets by soil analysis. PhD Thesis, Colorado State University.

(9) Giles, J. F., J. 0. Reuss, and A. E. Ludwick. 1975. Prediction of nitrogen status of sugarbeets by soil analysis. Agron. J. 67:454-459.

(10) Haddock, Jay L. 1952. The nitrogen requirement of sugar beets. J. Am. Soc. Sugar Beet Techr.:1 . 7 :159-169 .

(11) Haddock, J. L., P. B. Smith, A. R. Downe, J. T. Alexander, B. E. Easton, and Vernal Jensen. 1959. The influence of cultural practice on the quality of sugar beets. Am. Soc. Sugar Beet Technol. 10: 290-301.

(12) Halverson, A. D. and G. P. Hartman. 1975. Long-term nitrogen rates and sources influence sugar-beet yield and quality. Agron. J. 67:389-393.

VOL. 20 NO. 3 JULY 1979 231 (13) Hills, F. J. and Albert Ulrich. 1971. Nitrogen

nutrition. In R. T. Johnson, G. E. Rush, and J. T. Alexander (eds) Sugarbeet production, principles and practices. Iowa State Univ. Press, Ames .

(14) James, D. W. 1972. Soil fertility relationships of sugarbeets in central Washington: Phosphorus, potassium-sodium and chlorine. Tech. Bull. 69, Wash. Agric. Exp. Sta. 21p.

(15) James, D. W. 1971. Soil fertility relationships of sugarbeets in central Washington: Nitrogen. Wash. Agr. Exp. Sta. Tech. Bull. 68. 14p.

(16) James,D. W., A. W. Richards,W, H. Weaver and R. L. Reeder. 1967. Residual soil nitrate measurement as a basis for managing nitrogen fertilizer practices for sugarbeets. J. Am. Soc. Sugar Beet Technol. 16:313-322.

(17) Ludwick, A. E., J. 0. Reuss and J. F. Giles. 1974. Nitrogen fertilizer requirements of sugarbeets predicted by soil analysis. Colo. State Univ. Exp. Sta. PR 74-36 6p.

(18) Ludwick, A. E., J. 0. Reuss and J. F. Giles. 1973. Distribution of soil nitrates in eastern Colorado fields prior to planting sugar-beets. Colo. State Univ. Exp. Sta. PR 73-40 3p.

(19) Ludwick, A. E., P. N. Soltanpour and J. 0. Reuss. 1976. Guide to fertilizer recommendations in Colorado. Colo. State Univ. Cooperative Ext. Service publication. 45p.

(20) McDonnell, P. M., P. A. Gallagher, P. Kearney, and P. Carroll. 1966. Fertilizer use and sugar beet quality in Ireland. Potass. Symp. 1966. 107-26.

(21) Olsen, S. R., C. V. Cole, F. S. Watanabe, and L. A. Dean. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. USDA Circ. 939.

(22) Peterson, H. B., L. B. Nelson, and J. L. Paschal. 1953. A view of phosphate fertilizer investigations in 15 western states through 1949. USDA Circ . 927 .

(23) Raveh, Ariella. 1972. The adoption of the nitrate-specific electrode for soil and plant analysis. Soil Sci. 116:388-389.

(24) Reuss, J. 0., A. E. Ludwick, and J. F. Giles. 1973. Prediction of nitrogen fertilizer requirements of sugarbeets by soil analysis. Colo. State Univ. Exp. Sta. PR 73-39 4p .


(25) Reuss, J. 0. and P. S. C. Rao. 1971. Soil nitrate nitrogen levels as an index of nitrogen fertilizer needs of sugarbeets. J. Am. Soc. Sugar Beet Tech-nol. 16:461-470.

(26) Schmehl, W. R. and D. W. James. 1971. Phosphorus and potassium nutrition. p. 138-169. I_n R. T. Johnson, et al. , eds. Advances in sugarbeet production: principles and practices. The Iowa State Univ. Press, Ames.

(27) Skogley, Earl 0. 1975. Potassium in Montana soils and crop requirements. Montana Exp. Sta. Res. Report 88 . pp. 43-45 .

(28) Stout, Myron. 1961. A new look at some nitrogen relationships affecting the quality of sugarbeets. J. Am. Soc. Sugar Beet Technol. 11:388-398.

(29) Thompson, L. G. 1970. The influence of previous cultural practices on the yield and quality of sugarbeets. MS Thesis, Colorado State University.

(30) Ulrich, Albert. 1961. Plant analysis in sugar beet nutrition. Am. Inst. Biol. Sci. Pub. 8, p. 19 0-211 .

Bibliography: Methods of Sucrose Analysis* DOUGLAS W. LOWMAN

Received for publication March 6, 1978

Numerous methods for the quantitative analysis of sucrose

have been developed. Sucrose concentration may be deter

mined either by direct analysis of the intact sucrose or

by indirect analysis. Using indirect analysis, the sucrose

concentration can be quantitated by determining the concen-

tration of the hydrolysis products of sucrose — D-glucose

and/or D-fructose. In this bibliography, analysis methods

using the techniques of polarimetry, isotope dilution,

nuclear magnetic resonance spectroscopy, chromatography,

colorimetry and spectrophotometry, enzymatic analysis,

enzyme electrodes and titrimetry are summarized. It should

be realized that not every method of sucrose analysis can

be covered here. The coverage has been set at a level to

cover methods of sucrose analysis related to sugar beet

juices, in general, and to demonstrate the broad variation

in the methods available for sucrose quantitative analysis

and some of their problems.

Comparison of the accuracy of each individual method of

sucrose analysis relative to a standard method is not

straight-forward. The International Commission for Uni

form Methods of Sugar Analysis (ICUMSA) has considered

this question and has been unable to arrive at a consis

tent set of conclusions. Accuracies and precisions re

ported here are taken directly from the reference cited.

No attempt is made to relate the accuracy and precision

*Contribution from the Department of Chemistry, Colorado State University, Fort Collins, CO 80523. The author's pre-sent address is: Analytical and Development Services Labor-atory, Organic Chemicals Division, Tennessee Eastman Com-pany, Kingsport, Tennessee 37663.


results for each method quantitatively to a standard method

of analysis.

POLARIMETRY (SACCHARIMETRY)

Probably the most widely used method of sucrose analysis

in the sugar industry is polarimetry (39), referred to as

saccharimetry when applied to the measurement of sucrose

content. This method is based on the optical activity of

sucrose. Sucrose may be determined polarimetrically either

with a single polarimetric measurement or with double

polarimetric measurements in conjunction with sucrose

inversion by acid of enzymes.

Sucrose has been determined by a single polarimetric mea-

surement after destruction of reducing sugars (Muller

Method) (38) and in the presence of invert sugar (53).

Heating a sugar solution containing ethylenediamine results

in the destruction of the optical activity of lactose and

maltose allowing for the determination of sucrose by a

single polarimetric measurement (4). Sucrose has also been

determined by this method in the presence of glucose and

fructose by the addition of borax (2) and boron salts (17).

The direct polarimetric measurement of a sugar solution

gives the total rotation of all optically active species

present, and is, consequently, a correct measure of the

sucrose content only if the other substances present have

no effective rotatory power. If other optically active

species such as nitrogen-containing compounds (29) are pre-

sent, the single polarimetric measurement must be supple-

mented by a second polarimetric determination. In this

double polarization method, the optical activities of the

impurities are kept constant while any variations in the

total optical activity of the solution results from sucrose

hydrolysis to invert sugar. The variation is known to be

an exact function of the sucrose concentration. The

hydrolysis for analytical purposes can be effected by

either hydrochloric acid or the enzyme, invertase. The

method of double polarimetric measurements with hydro-

VOL. 20 NO. 3 JULY 1979 235

chloric acid inversion is the basis of the Clerget Method

(39) .

Two modifications to this method pertaining solely to the

hydrolysis time and temperature variations exist. These

are a modification by Browne (39) recommending overnight

hydrolysis at room temperature and a modification by Jack-

son and Gillis (23) showing inversion is complete in 8

minutes at 60°C under the conditions prescribed by Browne

(39) .

Nitrogen-containing compounds exhibit different rotatory

power in a neutral or alkaline medium. Thus, for best

results both polarizations in the double polarization

methods should be performed in solutions with similar hy

drogen-ion concentrations. In a promising proposal by

Stanek (39), potassium citrate was added in amounts

stoichiometrically equivalent to the hydrochloric acid

present after acid inversion, causing the formation of

potassium chloride and citric acid. To the solution with

no HCI present, equivalent amounts of potassium chloride

and citric acid were added, so that the two solutions were

more nearly alike. Babinski and Ablamowicz (39) replaced

the potassium citrate with sodium acetate. Jackson and

Gillis (23) proposed two other methods (II and IV) for

obtaining similar solutions. In Method II, sucrose inver

sion was accomplished by HCI, then neutralized with

NH OH. To a non-inverted sucrose solution was added

amounts of NH CI to equal that formed in the inverted solu

tion. In Method IV, no NH4OH was used as in Method II and

the NH CI was replaced by NaCI. Method II is generally

applicable. Method IV is applicable in the presence of

invert sugars, but not applicable in the presence of

optically active non-sugars which change rotation with

acidity.

It should be realized that hydrolysis by acid requires

careful temperature and time regulation. Also, hydro-

chloric acid is not selective, but hydrolyzes and glyco-


sidic group. Moreover, HCI influences the rotatory power

of invert sugar and many other impurities occurring in

natural products. For greater selectivity and no hydroly-

sisof impurities, the only appropriate procedure is hydroly-

sis by an enzyme specific for sucrose, e.g., invertase.

Sucrose determinations by double polarimetric measurements

with enzymatic inversion (39) were performed by procedures

similar to Browne's (39) or Jackson and Gillis' (23) modi-

fication of the Clerget Method, except invertase was used

in place of hydrochloric acid for the inversion.

Specific statements about the accuracy of each of these

polarimetric methods are difficult to make. In general,

precision for the polarimetric analysis of pure sucrose

solutions is + 0.1% (absolute) for manual determinations

and about +0.05% (absolute) for digital determinations.

Maag and Sisler (29) reported results of polarimetric

analysis to be generally high by 1 to 5% (relative) com-

pared to gas-liquid chromatography analysis (vide infra).

ISOTOPE DILUTION

Polarimetry is known to be unreliable in the presence of

optically active non-sucrose constituents. The isotope

dilution technique is not affected by interferences from

other species in solution. This technique measures the

yield of a non-quantitative process. A small amount of

radioactive sucrose is added to a sucrose solution. After

a non-quantitative purification of sucrose, the radio-

activity is measured. The extent of dilution of the radio

tracer indicates the amount of sucrose originally present.

Hirschmuller and coworkers (19,20,22) described the appli

cation of isotope dilution analysis to sucrose analysis in

sugar beets. The method of Horning and Hirschmuller (22)

required 3 to 5 days and, as such, was not useful for

rapid analysis. Sibley et al. (47) improved upon the time

constraints of the above method by reducing the experiment

time to 24 hours by streamlining the experimental proce-

dure. An accuracy of 0.1 to 0.2% (relative) was realized.

VOL. 20 NO. 3 JULY 1979 237

Mauch (32) detected a systematic error in the work of

Sibley et al. (47) and corrected it by doubling the amount

of water used in the digestion. Mauch found no systematic

error in the work of Horning ahd Hirschmuller (22). Liquid

scintillation counting techniques have been applied in iso

tope dilution studies (33) with no loss of accuracy over

gas-flow proportional counters (47), but with an increase

in the number of samples that can be analyzed, compared with

the methods described in previous reports.

CHROMATOGRAPHY

Chromatographic techniques*--paper chromatography (PC),

thin layer chromatography (TLC), high voltage paper elec

trophoresis (HVPE), ion exchange chromatography, and gas-

liquid chromatography (GLC)—have not found great applica

bility in the quantitative analysis of sucrose solutions.

The PC-Anthrone method of Sunderwirth, Olson, and Johnson

(52) used descending PC with ethyl acetate-acetic acid-

water (6:3:2) solvent system to easily separate 200 yg

each of sucrose, glucose, and fructose. The reproducibility

of the descending method was excellent using the colori-

metric anthrone method for determination of the sugar. The

standard deviation of the optical density for a 200 yg

sucrose sample was +1.6% (relative). This method allowed

for the analysis of 20 samples in 24 hours. Trojna and

Hubacek (54) separated D-glucose, D-fructose, and sucrose

by PC, enzymatically inverted sucrose, then detected the

invert sugars with a solution of either blue tetrazolium

or blue neotetrazolium. Maximum concentrations of 42 yg

D-glucose and 21 yg D-fructose per 10 milliliters of solu

tion were determined.

Fric and Kubaniova (11) separated sucrose from glucose and

fructose by PC using the solvent system butyl-alcohol acetic

acid-water (4:1:5), followed by colorimetric determination

of sucrose with triphenyl tetrazolium chloride. Accuracy

and reproducibility of the method for two samples contain-

*Colorimetric methods used with these chromatographic techniques are discussed later.


30 yg and 80 yg sucrose were

3.3 yg, respectively.

Mizuna and coworkers (35) separated sugars including su

crose by PC followed by colorimetric determination using

aniline hydrogen phthalate for aldoses and phoroglucinol

for ketoses.

Mixtures of sucrose esters, sucrose, and raffinose have

been separated by silica gel TLC on glass strips (14).

Separated species were eluted from the silica gel and

measured for sucrose content by the resorcinol-hydrochloric

acid colorimetric method of Roe (44). Raadsveld and Klomp

(43) described the determination of sucrose in the pre

sence of blucose and lactose after separation on cellulose

powder MN300 using water-ethyl acetate-pyridine (25:100:35)

solvent system. The standard deviation of the sucrose

analysis was (relative).

Welch and Martin (59) quantitated glucose, fructose and

sucrose using TLC and densitometry. The solvent system

employed was ethyl acetate-pyridine-water (8:2:1). The

relative standard deviation for sucrose in the concentra

tion range 6.00 to 14.73% was 7.2 to 15.1%.

Mabry and coworkers (30)applied HVPE to the separation of

sucrose in urine samples. Quantitation was accomplished

by densitometry with a standard deviation for sucrose deter-

minations of +9% at the 120 mg sucrose concentration level.

This method allowed for the analysis of 16 to 24 samples

per day.

Sinner, Simatupang and Dietrichs (50) demonstration the

use of borate complex ion exchange chromatography for the

separation and quantitation of sugars, including sucrose.

Sugars were determined colorimetrically with 0.1% orcinol

in concentrated sulfuric acid. Deviation of the individual

peak areas was about (relative) for repeated injection

of a sugar mixture. For quantitative measurement, of

VOL. 20 NO. 3 JULY 1979 239

sample was used for this separation technique requiring

70 to 90 minutes per separation.

The most promising chromatographic method for sucrose ana

lysis in sugar beet juices is the GLC method of Karr and

Norman (25). Separation was accomplished on a column pack

ed with 10% OV-17 (phenylmethyl-silicone) liquid phase on

Chromosorb W, 80/100 mesh. Precision was about

(relative) using trehalose as an internal standard. Su

crose concentrations ranged from 9.31 to 12.94 yg sucrose

per 100 of sample with standard deviation of yg

per 100 of sample.

NUCLEAR MAGNETIC RESONANCE (NMR) SPECTROSCOPY

Maciel and Lowman (31) quantitated sucrose content in sugar

beet juices by proton NMR. The method applied a new sol-

vent resonance elimination technique — Time Resolution

Water Eliminated Fourier Transform (TRWEFT) NMR - to re-

move the large water resonance from the proton NMR spectrum.

The TRWEFT NMR technique used an added paramagnetic relax-

ation reagent to preferentially relax the water protons

over the protons to be quantitated. The water resonance

was removed from the NMR spectrum by pre-truncating the

Free Induction Decay prior to calculation of the NMR power

spectrum. TRWEFT NMR with an internal standard gave a

linear response over the sucrose concentration range 0.0

to 0.810 M (i.e., 0.0 to 26.0 weight/weight % in water).

Accuracy for sucrose analysis in sugar beet juices was 0.50%

(absolute) relative to gas-liquid chromatographic analysis.

Precision for one solution was better than (abso

lute) at a sucrose concentration of 15.00%.

COLORIMETRY AND SPECTROPHOTOMETRY

Sucrose in 1.0 M HCI at 80°C hydrolyzes rapidly to glucose

and fructose. Fructose under the same conditions for a

period of 9.25 hours produces an ultraviolet chromophore

that is stable for 2 hours (12). The chromophore inten-

sity is a direct function of the sucrose concentration and,

as such, forms the basis for a simple, sensitive coloimetric


method of sucrose analysis. As little as 10 M sucrose can

be analyzed by this method in the absence of interfering

chromophores. The chromophore produced from the acid degra-

dation of fructose was found to be hydroxymethylfurfural

by thin layer chromatographic studies (12, 13). Furfurals,

after formation from sugars, have also been analyzed by

complex formation with azulene (46).

Analysis of small quantities of sucrose, on the order of

10-100 yg, has been performed colorimetrically by quanti

tation of the chromophore produced by the reaction of su

crose with anthrone (55). The chromophore formed was a

complex between anthrone and the fructose moiety of su

crose. Non-reducing fructosides (e.g., raffinose, melizi-

lose, and inulin) interfered.

The anthrone colorimetric technique has been employed in

numerous other investigations involving sucrose (9,36,37,

40,42,57,61). Accuracy to +_2% (relative) is obtainable for

the anthrone colorimetric method for typical sugar factory

samples containing about 0.2 yg of sucrose per milliliter

(51) .

Johnson et al. (24) combined enzymatic inversion of sucrose

by invertase with the anthrone method for determination of

sucrose in the presence of fructose and glucose. The repro-

ducibility of this method for glucose and fructose was

checked using 20 samples from a standard solution. The mean

absorbance for 100 glucose was 0.2757 +3.2% and for 50

yg fructose was 0.2379 +_3.2%.

Fresenius and coworkers (10) immobilized enzymes for re-

peated in vitro analysis of sucrose. These authors immo-

bilized the enzymes saccharase, hexokinase, phosphohexose-

isomerase and glucose-6-phosphate-dehydrogenase at CNBr

activated agarose. By means of this affinity absorption

method, they determined the sucrose concentration of solu-

tions in a closed system. The reduced form of nicotina-

mide dinucleotide phosphate measured spectrophotometrically

VOL.20NO.3JULY1979 241

was regenerated by means of glutathion reductase. Stan

dard deviation for a 7% sucrose solution was +0.02% (abso

lute) .

Papa and coworkers (41) quantitated sucrose concentration

in the presence of glucose and fructose by examination of

the differential reaction rates of sucrose reacting with

ammonium molybdate. Formation of the reaction product,

molybdenum blue, was followed spectrophotometrically.

Messineo and Musarra (34) described two methods for the

determination of sucrose based upon chromophore formation

in the reaction of the fructose moiety of sucrose with

cysteine or cysteine and tryptophan. The first method is

essentially a modification of Dische's cysteine reaction

optimized for temperature and sulfuric acid concentration.

The green chromophore formed in about 10 minutes, allowing

the determination of as little as 1 of fructose in about

30 minutes. The second method was based upon formation of

a pink chromophore by complexation of tryptophan with the

fructose-cysteine hydrochloride complex formed in the first

method. This second method required about 2.5 hours per

sample and was twice as sensitive as the first method.

Guyot (16) applied Hessler's method of fructose analysis

(18) to the analysis of sucrose solutions. Hessler's

method (18) employed the colorimetric determination of the

fructose complex with either p-anisidine or 3,3'-dimethoxy-

benzidine in 85% phosphoric acid in the presence of glu

cose. This analysis was good for fructose in the range

of fructose per gram of dry cotton boll. Guyot

(16) analyzed fructose and sucrose by their reaction with

p-anisidine. This reaction produced a yellow solution

after 1.5 hours. The analysis scheme was good for

fructose or 10-160 sucrose. The reproducibility of the

analysis was +1-2% (relative).

Lunder (28) developed a colorimetric sucrose analysis

scheme based upon reduction of cupric sulfate. Standard


solutions were prepared from Cu- 20 and measured spectrophoto-

metrically to obtain a standard curve over the range 100-

350 mg Cu 20. With this method, lactose, sucrose, maltose,

and glucose were determined by spectrophotometry measure

ment of the Cu 20 precipitated after reduction of the Cu(ll)

salt without the need for preparing and standardizing

titration solutions as Cajori (5) had to do.

In an earlier paragraph, the Kulka colorimetric method for

ketopentoses and ketohexoses (27) and the orcinol-sulfuric

acid method (56) for sugars were mentioned. The precision

of the sucrose analysis by these methods depended upon the

precision of the analysis for the monosaccharides, glucose

and fructose. Typical precision for glucose analysis by the

orcinol-sulfuric acid method was +l.4% (relative). The

Kulka method, based on the resorcinol-thiourea-HCI method

of Roe (44), involved the reaction of fructose with resor-

cinol in HCI with a small amount of FeCI3 present for

color enhancement. The error for fructose analysis was

+1% (relative).

ENZYMATIC ANALYSIS AND ENZYME ELECTRODES

Enzymatic analysis of sucrose has been carried out directly

by the action of the enzyme on sucrose or indirectly employ

ing sucrose selective electrodes. Von Voorst (58) re

ported the determination of lactose, maltose, and sucrose

by means of the differential action of yeast enzymes.

An 02-sensing electrode in conjunction with invertase,

mutarotase, and glucose oxidase was used by Satoh and co

workers (45) to analyze for sucrose in the range 0 to 10 mM.

The analysis scheme, measuring 02 uptake, required 3 min

utes. The standard deviation for 5 mM sucrose was +7%

(relative).

Cordonnier and coworkers (7) developed a magnetic enzyme

membrane for use in conjunction with a pO2 electrode and the

invertase-glucose oxidase enzyme system. The electrode

response was linear over the sucrose concentration range

243

TITRATION TECHNIQUES

Cajori (5) determined sucrose after acid hydrolysis in

the presence of glucose, fructose and maltose by iodometry

with an accuracy within 3% (relative). Cupric hydroxide

added to the sugar solution was reduced to Cu.O by the

sugar. The excess Cu(OH)2 reacted with an excess of potas

sium iodide, generating 12 which was quantitated by titra-

tion with sodium thiosulfate. Silin and Sapegina (48)

determined sucrose content by the difference in the amounts

of 1„ reacted before and after sucrose inversion. Raffi-

nose caused errors in this method.

Williams et. a_l. (60) investigated the quantitative oxida

tion of organic compounds including sucrose by potassium

iodate in concentrated sulfuric acid. Quantitation was

by sodium thiosulfate titration of the liberated 12. The

analytical accuracy was +1-2% (relative).

Celsi and Sarrailh (6) employed a cupric-argentimetric

reagent for the analysis of 5 to 10 ug sucrose by titra

tion of the cupric ion with KSCN. A mercurimetric titra

tion was employed by Belas and Soliman (1) for metallic

mercury liberated from K2 Hgl4 after reaction with the

aldehyde portion of sucrose. The titrant was sodium thio

sulfate. The mean recovery of sucrose over the range of

25 to 200 mg sucrose was 96.8+ 1.69%.

PHYSICAL CHEMICAL AND OTHER METHODS

Sucrose content has also been analyzed by measurement of

such physical properties as solution specific gravity (3),

viscosity (49), refractive index (21), and cryoscopic

measurements (8). Fluorometric analysis (15) of sucrose

using p-hydroxyphenyl-acetic acid as the substrate has

been accomplished over the sucrose concentration range

0.3 to 3.0 yg/ml (1 to 100 ug total). The precision was

about +_ 1.5% (relative). The method required an initial

enzymatic inversion with invertase. Katsuhiko and cowork-


ers (26) microbiologically assayed mixtures of glucose,

lactose and sucrose by lactic acid bacteria.

SUMMARY REMARKS

The isotope dilution method is the ultimate method of su

crose analysis, but it is also expensive and time consum

ing. The GLC method of Karr and Norman is just as accur

ate as the isotope dilution method, easy enough to be used

routinely in the laboratory, and requires about 12 minutes

per sample. For routine analyses, the GLC method can re

place the isotope dilution method in some cases as a means

of checking other methods of sucrose analysis.

In general, sucrose analysis by polarimetry, requiring about

2 minutes per sample, gives higher percent sucrose values

than analysis of the same samples by GLC. Maag and Sisler

(29) showed the error in sucrose analysis from polarimetric

analysis to be high by 1 to 5% (relative) compared to GLC

analysis of the same samples. This is probably due to

the presence of other optically active compounds in the

juices. Sucrose concentration errors by TRWEFT NMR analy

sis are generally in the range -3.3 to 3.6% (relative)

compared to GLC analysis of the same samples. Even at the

present state of TRWEFT NMR methodology, analysis by the

TRWEFT NMR technique is more reliable than analysis by the

polarimetric method.

The invertase double polarization method may be depended

upon to give reliable results. The two methods of Jackson

and Gillis (II and IV) give inflated results due to the

hydrolysis of the reversion products. The difference be

tween the sucrose result by Jackson and Gillis' Method II

and by the invertase method gives a relative measure of the

reversion products hydrolyzed by HCI. The amino compound

content can be determined by the difference in the results

from Jackson and Gillis' Methods II and IV.

Accuracy and precision of the other sucrose analysis methods

are generally not as good as the GLC, NMR, or isotope dilu-

VOL. 20 NO. 3 JULY 1979 245

tion methods. For reasons of time constraints and ease of

analysis, use of the polarimetric method for routine su

crose analysis has not been replaced by the methods discus

sed above. In the future though, analysis of sucrose con

tent in sugar beet juices may be performed by the GLC method

or the TRWEFT NMR method on a routine basis.

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Separation and Analysis of Some Sugars by Using Thin Layer

Chromatography SOULY FARAG*

Received for publication May 8, 1978

SUMMARY

Different sugars such as glucose, fructose, sucrose, raffi-

nose, and others have been separated on silica gel pre-

coated plates. The plates were doubly developed in one

direction with chloroform, acetic system consisting of

diphenylamine, aniline, and orthophosphoric acid in acetone.

The technique was used to analyze different sugars in beet

and juice samples.

INTRODUCTION

Great attention has been given recently to some relatively

rapid techniques of analysis. Thin layer chromatography

(T.L.C.) is already accepted as a laboratory tool for rou

tine work. Its low cost, ease, and rapidity along with

its capacity for separating and identifying small quanti

ties of compound mixtures make the technique a prime tool

for research as well. The objective of this investigation

was to adapt a method for separation, identification, and

approximation of different sugars in beet processing

liquors, thick juice from storage, and beet storage samples.

REAGENTS AND MATERIALS

1. Glass plates precoated with 0.25 mm dry silica gel,

EM reagents, EM Laboratories, Inc., 500 Exec. Blvd., Elms-

ford, NY 10523.

2. Solvent system which consists of a mixture of

chloroform, acetic acid, and water (3:3.5:0.5) by volume,

respectively.

* Sr. Research Chemist, U & I, Incorporated, Moses Lake, Washington 9 8837

252 JOURNAL OF THE A.S.S.B.T. 3. Spraying agent made from 1 gram diphenylamine and

1 ml of aniline in 100 ml acetone. This mixture is further

mixed with 85% orthophosphoric acid prior to use (10:1 v/v,

respectively).

PROCEDURE

1. ul is applied.

2. Dry the plate in air for approximately 30 minutes.

3. Irrigate with the solvent system in the ascending

direction in a tight container.

4. Allow the solvent to move upward about 12.5 cm.

This usually requires 90 minutes.

5. Remove the plate from the tank. Leave to dry in

air for about 30 minutes.

6. Place the plate back in the same developing solvent

and let the solvent move in the same direction to the same

distance of 12.5 cm. This usually takes 45 minutes. The

plates should then be dried in air for approximately 30

minutes.


Figure 1 is a thin layer chromatogram of some standard

sugar solutions which involve glucose, fructose, sucrose,

raffmose, and a standard invert solution (0.5% each of

glucose and fructose).

Figure 2 includes some standard sugar solutions (glucose,

fructose, sucrose, and r a f f m o s e ) . It also includes a

diluted thick juice sample (26 g in 100 ml) and a diluted

diffusion juice sample (1:1 by volume).

Figure 3 is a thin layer chromatogram of standard sugar

solution (0.5% of glucose, fructose, and sucrose); and

VOL. 20 NO. 3 JULY 1979 253 also some beet storage samples (diluted 1:1 by volume).

It should be pointed out that the conventional single

development technique when using cellulose precoated plates

resulted in sucrose tailing which interfered with the

determination of other sugars. On the other hand, the com

bination of double development and silica gel plates gives

separations with minimum or no sucrose tailing and with

improved resolution of other sugars.

Direct visual comparison with known standards provided

reliable semi-quantitative information. If greater accura

cy is required on quantitative analyses, the intensity of

the spots may be measured by transmission densitometry.

It should be pointed out that this method is most suitable

for the detection of many carbohydrates present in beets

and in factory juices. Because of the simplicity of the

method and the low cost of the equipment used, it is recom-

mended for use in support of beet storage studies, thick

juice storage analysis, and screening of agriculture

research samples.

me. . 5 * 1 trf

n»ff.

.St 1 ul

Std-Invert

.5* 2 ttl

61 u.

• * • »

Figure 1. Chromatogram of standard sugar solutions.


Figure 3. Chromatogram of some beet storage samples.

Effect of Chemicals on Sucrose Loss in Sugarbeets During Storage

W. R. A K E S O N , Y. M. Y U N , A N D E. F. S U L L I V A N *

Received for publication August 15, 1978

INTRODUCTION

Chemicals are used extensively in sugarbeet production but

relatively few chemicals have been evaluated to determine

adverse effects on root quality during storage. Nemati-

cides, herbicides and insecticides are applied to soil be

fore planting, at planting or to foliage after plant

emergence, and fungicides are applied to foliage in later

stages of growth. More recently, fungicides have been

applied to sugarbeet roots after harvest to control stor

age rots (8) .

Most storage investigations have involved treatment of the

foliage prior to harvest or the roots after harvest with

materials being tested to reduce sugarbeet storage losses.

Dilley et al. (6) reported that the respiration rates of

whole beets receiving postharvest treatments of potassium

azide, Merck HZ 3456, Botron and ethylene were higher than

those of non-treated beets. Wu et al. (10) reported that

preharvest applications of Randox, and postharvest dips

in N -benzyladenine and Randox solutions reduced the loss

of sucrose, raffinose concentration, and respiration

during storage; however, several chemicals applied as pre

harvest foliar sprays or postharvest dips increased sucrose

loss, reducing sucrose accumulation, or both.

Mumford and Wyse (9) reported that Penicillium and Botrytis

Spp. will infect beets wherever the surface is injured;

*The authors are Sr. Plant Physiologist, Entomologist, and Manager-Crop Establishment and Protection, The Great Western Sugar Company, Agricultural Research Center, Longmont, CO 8 0 501.


thereby, significantly increasing respiration and invert

sugar accumulation. A spray application of benomyl (Ben-

late) or thiabendazole (Mertect) at a concentration of

500 ppm prevented infection by these fungi during storage.

Thiabendazole controlled storage rot in commercial sugar-

beet piles when applied as a spray at a concentration of

1500 ppm (8).

These reports show that some preharvest and postharvest

applied chemicals increase sucrose loss and impurity ac

cumulation in whole sugarbeet roots during storage, whereas,

others may have a beneficial effect. The material pre

sented in this paper is a summation of research work con

ducted at Longmont, Colorado to determine whether a number

of commercial or potentially commercial agricultural

chemicals had any adverse effect on root quality in storage.

METHODS AND MATERIALS

HERBICIDES AND NEMATICIDES

Tests to evaluate herbicides were conducted in 1972 and

1973 and those to evaluate nematicides were conducted in

1972. Sugarbeets (GW MONO HY A 1) were grown in plots that

received herbicide treatments shown in Table 1 or nemati-

cide treatments shown in Table 2. Plots, 4 rows wide and

25 feet long, were replicated 6 times. Eighteen foot sec

tions from each row were harvested and washed. Roots from

rows 1 and 3 of each plot were analyzed immediately for

sucrose (2) and clarified juice purity (CJP) (3) while

those from rows 2 and 4 (25 to 35 lbs) were placed in

nylon net bags, identified with numbered safety pins and

placed into storage at 40 F. Thus, 12 samples of each

treatment were analyzed immediately while 12 samples were

stored. Respiration measurements were made daily as pre

viously described (1) at 40 F. Air which had been humidi

fied and scrubbed clean of carbon dioxide, flowed through

chambers containing beets, flushing out the carbon dioxide

given off by respiration of beets. The carbon dioxide was

captured in IN sodium hydroxide solution and then deter-

VOL. 20 NO. 3 JULY 1979 257 mined by back titration with 0.5 N hydrochloric acid to

phenolphthalin and. methyl orange end points. After respi

ration measurements were completed, the samples were ana

lyzed for sucrose, CJP and invert sugars (4).

GROWTH REGULATORS

A test of four growth regulators at two rates (Table 3)

each was established in 1971. The test was identical to

the herbicide and nematicide tests except that the chemi

cals were applied as foliar sprays 19 days prior to harvest.

None of the chemicals gave agronomic benefits and so were

not tested for storage loss in subsequent years.

FUNGICIDES

Evaluation of fungicides applied after harvest for control

of storage rot was made in 1976. Twenty-pound samples

were selected at random from two truck loads of machine

harvested MONO HY D2 beets. Eighteen samples were immedi

ately analyzed for sucrose and CJP. The remaining samples

were dipped in fungicide solutions shown in Table 4, for

30 seconds and then allowed to drain or were exposed to a

gaseous atmosphere of sulfur dioxide or ozone. Liquid

treatments included benomyl, thiabendazole, BayDam 18654,

Topsin M, and sulfur at 500, 1500, and 5000 ppm. Gaseous

treatments were sulfur dioxide at 1000 and 10,000 ppm for

24 hours or ozone at an undetermined concentration for two

hours. Two controls were included in the test. One con

trol received no treatment while the second was dipped in

water for 30 seconds. Eighteen replications were prepared

for each treatment. Respiration measurements were made

continuously from 7 through 133 days storage at 40 F.

When not in respiration chambers, beets were stored at

55 F for 45 days and at 40 F for the remaining time. After

104 days, 12 replications, and after 133 days, six replica

tions were analyzed for sucrose, purity and invert sugars.

Thiabendazole was evaluated in captive pile tests in 1977-

78 and 1978-79, and in a controlled temperature storage

test in 1978-79. One hundred 25-pound samples were pre-


pared from a truck load of commercially harvested MONO HY

D2 beets for each test. Fifty samples were left untreated

and 50 samples were sprayed with a 1500 ppm thiabendazole

solution at the rate of 50 ml per 25 lb sample. The sam

ples were turned over and resprayed to insure complete

coverage. Thus, a total of 100 ml of solution was applied.

The samples, placed in nylon net bags and identified with

safety pins, were stored in a commercial pile at Eaton,

Colorado, for 75 days in 1977-78; a commercial pile at

Berthoud, Colorado for 120 days in 19 78-79; and in a con

trolled temperature room for 9 8 days in 1978-79. The beets

were stored in the controlled temperature room at 55 F for

50 days and 40 F for 48 days at 100% relative humidity.

The purpose of this test was to have sufficient temperature

and humidity to produce mold growth. After removal, the

samples were analyzed for weight, sucrose, purity, raffi-

nose (7) and invert sugars.

RESULTS AND CONCLUSIONS

HERBICIDES AND NEMATICIDES

The herbicides and nematicides, when applied to the soil

before planting or to the foliage after emergence, had no

adverse effects on respiration, invert sugars after storage,

or sucrose loss (Tables 1 and 2 ) . Betanal perhaps had some

effect since respiration was significantly lower while in

vert sugars and sucrose loss of beets treated with that

compound were numerically lower than the control. The two

herbicide tests were averaged together for data in Table

1. None of the chemicals tested increased any of the stor

age loss parameters which may have been due to the early

treatment and lack of chemical residue at harvest.

GROWTH REGULATORS

The growth regulators listed in Table 3 have not been used

in commercial production, but the study illustrates the

potential effect of chemicals applied to the foliage prior

to harvest on storage loss. Two chemicals had no effect

on respiration, invert sugars, or sucrose loss at either

VOL. 20 NO. 3 JULY 1979 259 Table 1. Effect of herbicides on respiration, invert sugar accumula

tion and sucrose loss during storage. Mean of two years tests.

Invert sugar after storage. Harvest invert sugar was not determined.

Table 2. Effect of nematicides on respiration, invert sugar accumulation, and sucrose loss during storage.

Invert sugar after storage - harvest invert sugars are not available.

Telone = 78% 1,3 dichloropropane.

Table 3. Effect of preharvest applied growth regulators on respiration, invert sugar accumulation, and sucrose loss.

concentration. The other two chemicals had no effect at

the lower dosages, but significantly increased respiration

rate, invert sugar accumulation, and sucrose loss when the

dosages were increased four-fold. Even though the chemi

cals were applied to the foliage, sufficient material may

have been translocated to the roots to cause toxic effects.

Since the materials were applied only 19 days prior to

harvest, chemical residues undoubtly remained in the beets

after harvest to cause the effects. The test was original

ly set up to determine whether the chemicals might reduce

storage loss as was previously reported for Randox (10).

No chemical significantly reduced the storage loss param

eters. The limited data show that one is more likely to

increase or have no effect, than reduce storage loss by

preharvest applications of growth regulator chemicals.

FUNGICIDES

Postharvest applications of fungicides to roots for con

trol of fungus diseases which cause storage rots is a new

area of investigation for eventual commercial applications.

The storage rots cause abnormally high rates of sucrose

loss when beets are stored for the longer periods {100

days or more) of time. Microorganisms causing the rots

stimulate respiration by tissue damage, invert sugar accu

mulation, and accumulation of other impurities which in

hibit crystallization, thus adversely affecting processing.

Much rot and mold growth occur as a result of poor storage

handling conditions. Mechanical injury, dehydration,

freezing and thawing, high temperatures and poor pile

260 JOURNAL OFTHE A.S.S.B.T. Table 3 Cont.

VOL. 20 NO. 3JULY 1979 261

ventilation due to trash and soil inhance rot and mold

growth. The above conditions can be improved by careful

handling and good storage practices and may not be improved

by use of fungicides. Under some conditions when beets

have been properly handled and protected as under canopies,

extensive mold growth occurs during extended storage peri

ods of over 100 days. The studies described in this sec

tion were established first to determine the effectiveness

of several selected fungicides for control of storage rots

and second to determine whether chemicals might produce

phytotoxic effects which in turn could increase storage

losses.

Respiration rates for 28-, 91- and 133-day storage periods

and invert sugar accumulation after 104- and 133-day stor

age periods for beets treated with fungicides are given in

Table 4. Benomyl and Topsin M appeared to lower respira

tion during the early period (28 days) . The respiration

rates for benomyl and Topsin M treated beets decreased

relative to the control beets with increasing concentra

tions of the respective chemicals and became significant

at 5000 ppm. Mold growth was not evident after 28 days

and so the chemicals effect on respiration was probably

not related to mold control. The effect, if any, was

short lived since no improvement in respiration was seen

for benomyl or Topsin M after 91 or 133 days. Thiabenda

zole and BayDam 18654 at 5000 ppm and sulfur dioxide at

10,000 ppm had significantly higher respiration rates than

the non-treated beets after 91 days. After 133 days all

treatments were numerically higher than both controls,

with thiabendazole, Topsin M, and BayDam 18654 at 5000 ppm,

sulfur dioxide at 10,000 ppm and ozone treatments being

significantly higher than both controls.

Benomyl treatments at 500 and 1500 ppm showed the most

promise in reducing invert sugar formation at 104 and 133

days, although they were not significantly lower than the

check. Thiabendazole at 1500 and 5000 ppm, Topsin M at

5000 ppm, BayDam 18654 at 1500 and 5000 ppm, sulfur at

Table 4. Effect of fungicides applied at harvest on respiration rate and invert sugar formation during storage.

VOL. 20 NO. 3 JULY 1979 263

5000 ppm, sulfur dioxide and ozone increased invert sugar

to significant or near significant levels. High invert

sugar formation under these conditions may have been

caused by tissue damage from the chemicals or by micro

organisms which became established as a result of earlier

tissue damage. All treatments which significantly in

creased respiration also significantly increased invert

sugar accumulation.

Sucrose losses (initial sucrose - final sucrose adjusted

for weight change) were significantly increased by the

higher concentration of thiabendazole, Topsin M, BayDam

18654, sulfur dioxide and ozone (Table 5 ) . All treatments

Table 5. Effect of fungicides applied at harvest on sucrose loss during storage.


were numerically higher in sucrose loss than the controls

except 5000 ppm benomyl after 104 days. The sucrose

losses associated with chemical treatment are significantly

correlated with both respiration (r=0.58 for 91 days and

r=0.87 for 133 days) and invert sugar after storage (r=

0.80 for 91 days and r=0.82 for 133 days).

The treatments had a similar effect on respiration, invert

sugar and sucrose loss for both intermediate (104 days)

and long term (133 days) storage periods; however, the

differences between treatment and control became larger

with the longer storage periods. Correlation (r) between

intermediate and long term storage periods was 0.92, 0.85,

and 0.79 for respiration, invert sugar accumulation and

sucrose loss, respectively.

The control beets showed little evidence of rot and mold

even after 133 days storage. Without something to control

the chemicals would not be expected to reduce storage loss.

Several of the candidates appeared to be toxic at higher

concentrations as measured by increased respiration and

invert sugar formation. Thiabendazole at 1500 ppm applied

as a spray has been used commercially (8). Nearly three

times as much liquid can be adsorbed or absorbed by the

beet from a dip treatment than from a 2-gal. per ton. spray

treatment (unpublished data). Thus, more residue would

be left with the dip treatment than the spray treatment

and so toxicity would be expected to be greater with the

former treatment than the latter.

Sucrose and recoverable sucrose losses in Thiabendazole

treated beets (1500 ppm with spray application) were com

pared with non-treated beets in three tests in 1977-78

and 1978-79 (Table 6 ) . Recoverable sucrose losses were

significantly higher in thiabendazole treated beets than

non-treated beets stored as captive samples in commercial

piles at Eaton and Berthoud, Colorado. Recoverable sucrose

loss of thiabendazole treated beets averaged 13% greater


than non-treated beets in the two tests. No significant

differences existed in sucrose loss between the two treat

ments in the Eaton and Berthoud tests, but in each case,

the purity was slightly lower in the treated beets after

storage (Table 7 ) . Little, if any, mold was observed on

the beets in either test. Losses of beets in the Eaton

test were higher than normal which may have been caused

by crown frost two days before harvest. Temperature and

moisture conditions in the third test were set up to en

courage mold growth. The sucrose and recoverable sucrose

losses in treated beets were significantly less than in

non-treated beets. Purity was also significantly better

in treated beets after storage than in non-treated beets.

Visual observations showed thiabendazole reduced mold in

the third test. These data show that thiabendazole re

duced storage losses by reducing rot and mold in beets

stored under conditions which promote mold growth, as

would occur in canopy covered piles. The treatment gave

no benefit and may actually increase losses relative to

the non-treated beets under conditions where little mold

occurs. These conditions would exist under short and

intermediate term storage periods in piles which are not

covered with a canopy.

The following conclusions have been made from the studies

reported in this paper:

1) Some chemicals increase respiration, invert sugar

formation, and sucrose loss in stored beets. The

toxicity increased with increasing dosage of the

chemical and with the chemicals applied just prior

to or after harvest.

2) None of the herbicides or nematicides applied at rec

ommended rates and times gave detectable increases in

respiration, invert sugar formation, or sucrose loss.

These materials applied early in the season would

have little residue left at harvest to produce toxic

effects in roots. New pesticide candidates, however,

should be evaluated for their effect upon storage

loss before being put into commercial use.

VOL. 20 NO. 3 JULY 1979 267 3) Fungicides are useful in reducing rot and mold under

some storage conditions (8, 9 ) , but their use should

be limited to areas of known potential problems (such

as long term storage, canopy covered piles, or a

known history of problems). If no mold problems

exist, the fungicides may increase storage losses.

4) Cultivars differ widely in respiration rate, invert

sugar accumulation, and sucrose loss (1, 5, 1 1 ) .

Cultivars could likewise vary in their storage loss

reaction to chemical treatment, but we have no evi

dence to indicate this is true.

SUMMARY

The chemicals applied early in the season such as herbi

cides or nematicides had no adverse effect on respiration,

invert sugar formation, or sucrose loss during sugarbeet

storage; however, many chemicals applied prior to or after

harvest significantly increased storage loss, no doubt

because of toxicity to the beets. The losses increased

with increasing rate of application.

Certain fungicides applied to the roots after harvest re

duced storage losses in situations where rot and mold

problems exist; however, they may increase losses where

little or no mold problems exist.

(1) Akeson, W. R. , S. D. Fox, and E. L. Stout. 1974. Effect of topping procedure on beet quality and storage losses. J. Am. Soc. Sugar Beet Technol. 18:125-135.

(2) Brown, C. A. and F. W. Zerban. 1941. Physical and chemical methods of sugar analysis. John Wiley and Sons, NY. pp. 337-374.

(3) Carruthers, A. and J. F. T. Oldfield. 1962. Methods for assessment of beet quality. In The technological value of the sugar beet. Proc. 11th C.I.T.S. pp. 224-245. Elsevier Pub. Co. NY.

(4) Carruthers, A. and A. E. Wooten. 1965. A color-metric method for determination of invert sugar in the presence of sucrose using 2,3,5 Triphenyl tetrazolium chloride. Int. Sugar J. 57:193-194.

(5) Cole, D. R. 1977. Effect of cultivar and mechanical damage on respiration and storability of sugar-beet roots. J. Am. Soc. Sugar Beet Technol. 19: 240-245.

(6) Dilley, D. R., R. R. Wood, and P. Brimhall. 1970. Respiration of sugar beets following harvest in relationship to temperature, mechanical injury and selected chemical treatment. J. Am. Soc. Sugar Beet Technol. 15:288-293.

(7) McCready, R. M. and J. C. Goodwin. 1966. Sugar transformation in stored sugarbeets. J. Am. Soc. Sugar Beet Technol. 14:197-205.

(8) Miles, W. G., R. M. Shake, and A. Kent Nielson. 1978. The control of beet rotting fungi in sugar-beet piles by TBZ in Washington. 20th Meeting ASSBT, San Diego, CA. Feb. 26-March 2, 1978.

(9) Mumford, D. L. and R. E. Wyse. 1976. Effect of fungus infection on respiration and reducing sugar accumulation of sugarbeet roots and use of fungicides to reduce infection. J. Am. Soc. Sugar Beet Technol. 19:157-162.

(10) Wu, M. T., B. Singh, J. C. Theurer, L. E. Olsen, and D. K. Salunkhe. 1970. Control of sucrose loss irfc sugarbeet during storage by chemicals and modified atmosphere and certain associated physiological changes. J. Am. Soc. Sugar Beet Technol. 16:117-127.

(11) Wyse, R. E., K. C. Theurer, and D. L. Doney. 1978. Genetic variability in post-harvest respiration rates of sugarbeet roots. Crop Sci. 18:264-266.

268 JOURNAL OF THE A.S.S.B.T. LITERATURE CITED

Effect of Injury on Respiration Rates of Sugarbeet Roots*

R. E. W Y S E AND C. L. PETERSON

Received for publication October 2, 1978

Introduction

When sugarbeets are first placed into storage, pile temper

atures are the warmest and respiration rates are the high

est (4, 6 ) . Therefore, losses during the first weeks of

storage may be an important part of the total losses

incurred. Previous workers have shown the effects of

mechanical damage and topping on respiration rates and on

sucrose losses during extended storage (1, 2, 3, 4, 7 ) ,

but little information is available on the relationship

between injury and respiration immediately after harvest.

The objective of this investigation was to determine the

effect of harvest injury on respiration rates immediately

after harvest and to determine the feasibility of using

respiration as an injury index.

Materials and Methods

To determine the effects of normal harvest procedures on

respiration, sugarbeet roots were randomly selected from

various points in the harvest, handling, and piling process

at the Fremont factory of the Northern Ohio Sugar Company.

Sugarbeet roots from a single farmer were sampled 1) from

*Cooperative Investigations of Agricultural Research, the Science and Education Administration, U. S. Department of Agriculture; the Beet Sugar Development Foundation; and the Utah State Agricultural Experiment Station and Idaho Agricultural Experiment Station. Approved as Journal Paper No. 2324, Utah Agricultural Experiment Station, Logan, Utah, 84322. The authors are Plant Physiologist, U. S. Department of Agriculture, Science and Education Administration, Agricultural Research, Crops Research Laboratory, Utah State University, Logan, Utah, 84322; and Professor of Agricultural Engineering, University of Idaho, Moscow Idaho, 83843.

270 J O U R N A L O F T H E A.S.S.B.T.

the top of a load of beets (harvester with grab-roll

screen); 2) after unloading over a grab-roll screen;

3) and after washing with a mechanical washer-piler. The

mechanical washer was a modified grab-roll screen having

small, rough protrusions on the surface of the rolls. These

rolls inflicted severe abrasion wounds on the surface of the

roots. As controls, roots from the same field were hand dug

and washed with a hose and spray nozzle. A second control

sample was taken from the grab-roll screen on the piler

before the beets entered the washer. These roots were also

hand washed. The roots were transported to East Lansing,

Michigan, for respiration analysis. Respiration measure

ments were begun two days after harvest.

In a second experiment, the effect of temperature on the

respiration rate of injured roots immediately after harvest

was determined. Roots were hand harvested between 8 and

10 a.m. Root temperature was 15° C at the time of harvest.

Injury was inflicted by dropping each root individually

150 cm onto an asphalt surface. Types of injury were

surface abrasions and some cracking. The roots were placed

in respiration chambers at 2 and 10° C and the first

respiration measurements were made less than 6 hours after

harvest. Temperatures were monitored with thermocouples

inserted 3 cm into a root of representative size. Root

temperatures stabilized at 10° C after 10 hours but re

quired 16 hours to stabilize at 2° C.

In a third experiment, hand-dug roots were topped with a

standard tare topper. Impact injury was inflicted by

dropping a 2 kg weight from 61 cm onto the surface of the

roots. Each root was impacted twice--once on each side.

The respiration rate was then monitored at 10° C for

11 days.

In a fourth experiment, the effect of injury occurring in

the harvesting and handling operation on respiration rates

was determined by comparing 8 treatments. 1) Hand dug-

untopped; hand harvested with only petioles removed;

V O L . 20 N O . 3 JULY 1979 271

2) Hand dug-topped; hand harvested with crowns removed;

3) Hand dug-machine topped; flailed and scalped with roto

beater; 4) Hand dug-gouged; topped with standard tare

machines and gouged 3 times (gouges were conic in shape,

25 to 40 mm deep and 40 mm in diameter); 5) Hand dug-

through piler; roots passed across a standard piler after

removal of the crowns with a standard tare machine;

6) Flat plate impact; beets were dropped 2 M onto a flat

metal plate; 7) Mechanically harvested-off truck; lifter-

load type harvester with samples collected from the top

of the truck in the field; 8) Mechanically harvested-off

pile; as in 7 ) , beets passed across a standard piler and

the roots collected from the storage pile.

Beets were obtained from the Beatrice station of U and I

Sugar Company in Washington and transported to the Moses

Lake research lab for analysis. Seven replications of

each treatment with 7 to 10 kg per treatment were placed

in plastic pails. Respiration rates were measured daily

for 95 days. Temperature in the chamber was maintained

at 2° C except for twice when mechanical difficulties

caused the chamber temperature to increase.

Respiration rates were measured with an automated flow-

through system. Samples of three to six beets with a

total weight of 2.5 to 8 kg were placed in 24-liter,

plastic pails. Air was introduced into each pail at a

calibrated rate of 500 ml/min. The increase in carbon

dioxide level of the air was determined with an infrared

gas analyzer. All data were corrected to standard

temperature and pressure and respiration rates were

expressed as carbon dioxide produced per kilogram fresh

weight.

Results

The respiration rates of roots sampled during the harvest

ing and handling process reflected the amount of injury

inflicted (Figure 1 ) . The hand-harvested roots with

minimal injury (topped with a tare topper) had the lowest

Figure 1. Respiration rate of sugarbeet roots subjected to various degrees of harvest and handling injury. Temperature, 10° C.

When roots were placed in storage at 10° C, respiration

rates increased rapidly to a maximum during the first

24 hours and then decreased to a stable rate after 11

days (Figure 2 ) . The injured roots reached a peak 10 hours


respiration rate, and the severely injured machine-washed

beets had the highest. Each step in the handling process

caused an incremental increase in respiration that was

sustained throughout the 12 days at 10° C. These data

indicated that the effect of injury existed well beyond

the initial high respiration period. These data also

indicated the sensitivity of respiration as an indicator

of relative injury in sugarbeets.

VOL. 20 NO. 3 JULY 1979 273

before the uninjured controls and then their rate parallel

ed that of the controls. The injured roots were still

respiring at a rate 25 percent higher than that of the

hand-dug controls after 11 days.

At 2° C there was no apparent increase in respiration

during the initial 24 hours, but approximately 10 days

were required for the respiration rate to stabilize.

After 10 days the injured roots were respiring at a rate

43 percent higher than that of the hand-harvested controls.

The effect of topping and impact damage on sugarbeet root

respiration at 10° C is shown in Figure 3. Crown removal


greatly increased respiration rates during the first 96

hours of storage. However, after this time the topped

roots respired at a lower rate than the untopped roots.

Impact injury increased the respiration rate of topped

and untopped roots by 5.6 and 8 percent, respectively.

To determine why untopped roots respired at a higher rate

than the topped roots, the respiration rate of topped and

untopped roots and crowns was determined. Roots previously

stored for 3 0 days at 5° C .were used. Roots were topped

by removing the crown at the lowest leaf scar. The crown

V O L . 20 N O . 3 JULY 1979 275

tissue removed represented 13.4 percent of the weight

of the original root. Respiration rates were then deter

mined at 5° C. The topped roots respired at a lower

rate (4.49) than the untopped roots (5.09). The crown

tissue respired at a rate approximately three-fold higher

than that of the topped root (14.1 vs. 4.49). Therefore,

the higher respiration rate of untopped roots can be

explained by the high respiration rate of the crown

tissue. The effect of topping injury can be estimated

as follows:

(7o weight of roots x resp. of roots) + (% weight of crown)

x (resp. of crowns) = Total resp.

(4.49 x 0.866) + (14.1 x 0.134) = 5.78

5.78 - 5.09 = 0.69, or 14%

Therefore, topping increased respiration rates approximately

14 percent.

The increase in respiration due to the degree of damage

and the effect of mechanical handling operations for the

95-day time period is shown in Figure 4. Figure 5 shows

the average respiration rate for each treatment for the

entire storage period. For the first 20 days the

artificially damaged treatments had higher respiration

rates than the rest of the samples. For the remainder of

the storage period, samples taken from the storage pile

and from the top of the truck had the highest respiration

rates. Considering the severe damage inflicted to the

beets in the artificial damage treatments, it is signifi

cant that the ordinary methods of handling beets resulted

in even higher rates of respiration. Hand harvested

samples either topped or untopped had consistently lower

rates of respiration than the other treatments. The

beets with crowns removed and otherwise undamaged

generally had lower rates of respiration than those with

the crowns intact, but the differences were not statisti

cally significant.

Therefore, topping increased respiration rates approximately

14 percent.

The increase in respiration due to the degree of damage

and the effect of mechanical handling operations for the

95-day time period is shown in Figure 4. Figure 5 shows

the average respiration rate for each treatment for the

entire storage period. For the first 20 days the

artificially damaged treatments had higher respiration

rates than the rest of the samples. For the remainder of

the storage period, samples taken from the storage pile

and from the top of the truck had the highest respiration

rates. Considering the severe damage inflicted to the

beets in the artificial damage treatments, it is signifi

cant that the ordinary methods of handling beets resulted

in even higher rates of respiration. Hand harvested

samples either topped or untopped had consistently lower

rates of respiration than the other treatments. The

beets with crowns removed and otherwise undamaged

generally had lower rates of respiration than those with

the crowns intact, but the differences were not statisti

cally significant.


Discussion

It was apparent that injury during harvest and handling

had a significant effect on the respiration rate of

sugarbeet roots during at least the first 10 days of

storage. Injury as slight as dropping a 2 kg weight 60

cm onto the surface of roots was readily detectable,

even on beets previously inflicted with topping injury.

Therefore, respiration should be a useful technique for

monitoring sources of injury in the handling of

sugarbeets.

Injury to sugarbeet roots during harvesting, handling,

and piling may have a significant effect on their ability

for storage. Injury not only increases respiration rates

VOL. 20 NO. 3 JULY 1979 277

but also facilitates infection by fungal agents. Mumford

and Wyse (5) found that the epidermal layer must be

broken before infection by Penicillium or Botrytis can

occur. Therefore, reducing surface injury to sugarbeet

roots should significantly reduce sucrose losses resulting

from respiration and mold growth during storage.

The respiration rate immediately after harvest is very

important, not only as a factor in sucrose loss, but also

as a producer of heat. This heat of respiration is a

major source of heat that must be removed from a storage

pile before it can be cooled significantly. The rate of

cooling during this initial period can significantly

contribute the total sucrose lost during the entire

storage period (8).

278 J O U R N A L O F T H E A.S.S.B.T.

The controversial question of whether it is better to

remove the crown near the lowest leaf scar or to merely

remove all green material was not clarified by this study.

Crown removal by knife or tare machine increased respiration

rates during the first 5-10 days of storage. However,

after this time topped beets respired at a lower rate than

did untopped beets. Apparently the higher respiration

rate of the crown tissue had a greater effect after 5-10

days than did the increased respiration resulting from

topping injury. When a field topper was used as in

Experiment 4, even though hand harvested, the beets

continued to respire at a high rate throughout the 95-day

period. The reason for this conflict may be explained

by the fact that the tare machine would inflict less

damage and leave a smoother cut than the field topper.

These results confirmed those of Akeson and colleagues (1)

which indicated that mechanically topped roots respired

faster than untopped roots during an entire 180-day period

of storage.

Numerous studies have shown that, although the crown con

tains less sucrose and has a lower purity than the root,

its contribution to recoverable sugar per acre can be

considerable (3, 9 ) . Stout and Smith (7) found that

topped beets respired faster and spoiled quicker than

untopped beets. The greatest spoilage was in beets topped

near the center of the crown and resulted from exposure

of the pith area to fungal organisms (1, 3 ) .

VOL. 20 N O . 3 JULY 1979 279

Acknowledgements

The samples for the data presented in Figure 1 were

collected by Phil Brimhall, Northern Ohio Sugar Company

(presently Michigan Sugar Company) and the respiration

analyses were run on equipment provided by Dr. David Dilley,

Michigan State University. Data in Figure 1 was previously

published in Beet Sugar Technology, p. 97. In R. A.

McGinnis (ed.), Beet Storage, 1971. The cooperation of

U and I Incorporated in providing respiration analyses

for Experiment 4 is greatly appreciated. This research

was supported in part by grants from the Beet Sugar

Development Foundation.


Literature Cited

(1) Akeson, W. R., S. D. Fox, and E. L. Stout. 1974. Effect of topping procedure on beet quality and storage losses. J. Am. Soc. Sugar Beet Techno1. 18:125-135.

(2) Cole, D. F. 1977. Effect of cultivar and mechanical damage on respiration and storability of sugarbeet roots. J. Am. Soc. Sugar Beet Technol. 19:240-245.

(3) Dexter, S. T., M. G. Frakes, and R. E. Wyse. 1970. Storage and clear juice characteristics of topped and untopped sugarbeets grown in 14- and 28-inch rows. J. Am. Soc. Sugar Beet Technol. 16:97-105.

(4) Dilley, D. R., R. Ralph Wood, and Phillip Brimhall. 1970. Respiration of sugarbeets following harvest in relation to temperature, mechanical injury and selected chemical treatment. J. Am. Soc. Sugar Beet Technol. 15:671-683.

(5) Mumford, D. L. and R. E. Wyse. 1976. Effect of fungus infection on respiration and reducing sugar accumulation of sugarbeet roots and use of fungicides to reduce infection. J. Am. Soc. Sugar Beet Technol. 19:157-162.

(6) Oldfield, J. F. T., J. V. Dutton, and B. J. Houghton. 1971. Deduction of the optimum conditions of storage from studies of the respiration rates of beet. International Sugar Journal 73:326-330.

(7) Stout, M. and C. H. Smith. 1950. Studies on the respiration of sugarbeets as affected by bruising, by mechanical harvesting, severing into the top and bottom halves, chemical treatment, nutrition and variety. Proc. Am. Soc. Sugar Beet Technol. 6:670-679.

(8) Wyse, R. E. and R. M. Holdredge. 1975. A computer simulation model for predicting pile temperatures and sucrose losses in sugarbeet storage structures. In: Recent Developments in Sugarbeet Storage Techniques, proceedings of~the BSDF Conference, Denver, CO.

(9) Zielke, R. C. 1973. Yield, quality, and sucrose recovery from sugarbeet root and crown. J. Am. Soc. Sugar Beet Technol. 17:332-334.

Remedying Inadequate Crystallizer Capacity R. A. MCGINNIS*

Received for publication November 27, 1978

Much money is lost each year by beet-sugar manufacturers

from excessive loss of sucrose in molasses. There is too

much money involved to sell sugar at bargain prices to feed

cattle, when it can be sold for a good profit as the re

fined product.

A factory slicing 4,000 tons of beets a day and making 5%

molasses on beets, will make 1400 tons of molasses per week.

Assuming values of $300 and $37 per ton of sugar and molas

ses, respectively, the $ per ton of molasses saved by lower

ing the molasses purity one point from 61% to 60% purity

would be $5,075, or $7105 per week.

For a company slicing 5 million tons of beets per year, and

making 250,000 tons of molasses, the one unit purity drop

would involve $1.28 million. If the molasses purity was

reduced to its probable lowest practical or "normal" puri

ty value of 56%, the gain per ton of molasses would be

*Formerly Amstar Corporation/Spreckels Sugar Division, San Francisco, CA; Now Consultant, San Rafael, California

averages 60.4 5 8 . 1 - 6 3 . 7

The low values for the factories of company "A" are omitted

from the averages because they are from factories using a

special auxiliary process. The purities are Clerget num

erators over 1:1 diluted rds denominators. While several

manufacturers have made appreciable progress in reduction

of molasses purities, as a whole the overall purities are

still uneconomically high.

Figure 1 shows a flow plan for a typical raw crystalliza

tion station, consisting of a feed-supply tank for the pan,

the raw vacuum pan, a receiver (mixer) for the finished mas-

secuite from which the crystallizers are fed (in the case

of batch crystallizers these are not needed), a mingler-

reheater, and finally centrifugals to separate the molas

ses from the raw sugar.

Figure 1 . Typ ica l raw c r y s t a l l i z a t i o n equipment .

DETENTION TIMES IN EQUIPMENT

I t i s commonly a c c e p t e d among t e c h n o l o g i s t s t h a t i n o r d e r t o comple te t h e c r y s t a l l i z a t i o n o f m a s s e c u i t e which has been p r o p e r l y b o i l e d i n t h e vacuum pans w i t h t h e u s u a l p a n -d r o p p i n g t e m p e r a t u r e o f a b o u t 70°C, a t l e a s t 30 h o u r s in t h e c r y s t a l l i z e r s a r e r e q u i r e d , c o o l i n g t o a low p o i n t t e m p e r a t u r e o f 40°C. Th i s i s i n a d d i t i o n t o t h e a p p r o x i mate 4 hou r s s p e n t in t h e r e c e i v e r - Tab le 2 shows d e t e n t i o n t imes i n Nor th American f a c t o r i e s .

Table 2 . Ac tua l d e t e n t i o n t imes in hours i n raw c r y s t a l l i z i n g equipment in North American f a c t o r i e s , 1976-77 campaign. (Cour tesy Beet Sugar I n s t i t u t e ) . I t should be no ted t h a t fo r Tab l e s 1 , 2 , and 3 , t h e l e t t e r d e s i g n a t i o n s do no t r e p r e s e n t t h e same companies in each t a b l e , t o b e t t e r p r o t e c t t he anonymity.

VOL. 20 NO. 3 JULY 1979 283

Three companies using batch crystallizers with Blanchard

type agitators are not meeting this requirement; the two

companies using Lafeuille crystallizers are very deficient

in detention times, and two of the companies using continu

ous crystallizers have time shortages.

Thus even though all other variables affecting raw crys

tallization were in satisfactory condition, which of course

is not the case, these crystallizer capacity shortages need

rectification.

Addition of more crystallizer units is an unpleasant path.

A crystallizer unit today costs about $300,000 f.o.b., and

probably involves another $100,000 installed. There is

likely to be a space problem. Most factories do not have

empty spaces for such equipment, and the solution to this

might be the installation of the new vertical-type units

such as the Toury and the B.M.A., which can be placed on

the ground outside the factory building, and connected with

magma pumps.

HIGH TEMPERATURES

Since the purpose of this paper is to call attention to

this variable, it will be given more attention than other

equally important variables. A fundamental principle of

sugar crystallization is that as much as possible should

be done as far "upstream" as possible. This is, of course,

because higher temperatures are normally used with higher

purity materials, and crystallization rates are more rapid,

and there are more control variables which can be advan

tageously manipulated in the vacuum pan, such as better

agitation, sensitively adjusted supersaturation, syrup

VOL. 20 NO. 3 JULY 1979 285

additions, and others. This paper examines primarily the

variable of boiling temperature as it affects the crystal

lization rates.

All the crystallization possible should be done in the

white boiling, then all possible of the remainder in the

intermediate boiling, and the green syrup from this boil

ing serves as the feed material for the raw pans. Both

white and intermediate mixers should be kept on the full

side as much as possible, without causing problems in mix

ing the grain of different strikes of massecuite. The

centrifugals should be operating all the time between pan

drops, with no "holes" or idle periods.

In the raw crystallization system, all possible should be

accomplished in the pan, and again the raw mixer should be

kept on the full side, as considerable crystallization can

be done there. The final unit is the mingler-reheater,

and if a Stevens type is used, the upper hopper should be

kept as full as possible. One factory gains as much as

1 purity point lowering of the molasses, as compared to

keeping the level very low.

It is my opinion that most factories are not boiling their

raw strikes at temperatures as high as possible without

degrading the juice, and are thus wasting valuable crystal

lization potential.

Table 3 shows the temperatures in raw crystallization

units in 1976-77.


Note that "From vacuum pan" values are the massecuite temp

eratures after being "Brixed-up," which in a pan without

absolute pressure control, often increases the temperature

over that of the rest of the boiling. Considering this,

it seems probable that only one company has consistently

carried a higher than usual boiling pattern.

EFFECT OF TEMPERATURE ON RATES OF CRYSTALLIZATION

It is a well-known "rule of thumb" among chemists that,

on an average, an increase of temperature of 10°C will

approximately double a crystallization rate. This is a

very rough approximation, and deviations from it can be

very wide, and even reversed.

Some data from the literature are reproduced to show the

temperature effects on sucrose crystallization.

VOL. 20 NO. 3 JULY 1979 287 Table 4 shows d a t a from Kukharenko, on pu re s u g a r - w a t e r s o l u t i o n s .

U n f o r t u n a t e l y n o d a t a a r e r e a d i l y a v a i l a b l e i n t h e 8 0 ° -85°C r e g i o n . S u s i e (5) conduc ted f a c t o r y s c a l e t e s t s a t 80°C, w i t h o b v i o u s l y v e r y r a p i d r a t e s o f c r y s t a l l i z a t i o n . A t t emp t s a t measu r ing such r a t e s i n t h e l a b o r a t o r y have i n d i c a t e d t h e y a r e s o r a p i d t h a t p r e c i s e c o n t r o l i s d i f f i c u l t on a s m a l l s c a l e .

Thus , i f t h e b o i l i n g t e m p e r a t u r e i s r a i s e d a s h igh a s can be done w i t h o u t d e g r a d a t i o n o f s u c r o s e o r n o n s u c r o s e s , t h e r a t e s o f c r y s t a l l i z a t i o n w i l l b e q u i t e r a p i d . A s t h e conc e n t r a t i o n o f t h e s u c r o s e i n t h e mother l i q u o r i s lowered i n t h e l a t t e r p a r t o f t h e b o i l i n g , t h e m a s s e c u i t e t e m p e r a t u r e w i l l have t o b e lowered g r a d u a l l y t o m a i n t a i n t h e s u p e r s a t u r a t i o n , and a f t e r t i g h t e n i n g , t h e pan w i l l end a t about 70°C, w i t h a maximum amount of c r y s t a l l i z a t i o n p e r formed. There w i l l b e much l e s s f o r t h e c r y s t a l l i z e r s t o


do, and if supersaturations are kept optimum in them, the

total crystallization achieved will be much more than if

the pan had accomplished less. The percent gross crystal

lization (percent on sugar in the pan feed) should be close

to 60%, and with 6 to 8% added by the crystallizers, better

molasses exhaustion should result.

The percentage of crystallization in a pan boiled by this

"hot" technique, if the massecuite is properly tightened

and dropped at 70°C will be the same as in a boiling at

a lower temperature, but much less boiling time will have

been required, and certain slow-boiling massecuites (be

cause of the nature of their nonsucroses) will crystallize

much more rapidly. There will be much less for the crys

tallizers to do, and if the factory is short of crystallizer

capacity, probably the best possible results with the exist

ing equipment will be attained.

It should be kept in mind, however, that this "hot" boil-

VOL. 20 NO. 3 JULY 1979 289

ing technique will be of much less, or no interest at all,

if the factory has ample crystallizer capacity, - enough

to give crystallizer detention times or 30 - 40 hours or

more -

Figure 4. Viscosity of typical beet molasses, 1, and pure sucrose water solution, 2, at various temperatures. Both are at 1.0 saturation (5).

VISCOSITY

When boiling at high temperatures it is necessary to keep

the rds of the massecuite high, not only because of the

more rapidly-increasing mass of crystals, but also to main

tain high enough supersaturation.

Fortunately viscosities of the syrup phases will not in

crease appreciably. The recently published work of Karad-

zik and Terek (2) shows that in the ranges of rds and

temperature which would be involved in high-temperature

boiling, the syrup viscosity changes only by a few poises

at constant saturation, and we may reasonably assume, at

constant supersaturation. This is shown clearly in Fig

ures 3 and 4.

FACTORS IMPORTANT IN HIGH-TEMPERATURE BOILING

1. The molasses produced must have a pH value higher than

6.9. If lower, milk of lime or magnesia should be added

to any of the following: intermediate boiling, raw pan


feed, or the raw pan. Do not use caustic soda or soda

ash, as these are very melassigenic.

2. Temperatures should be raised by degrees when first

trying high temperature boiling. Watch for evidences of

degradation, such as inversion, or color increase, not

only in the massecuite as discharged, but also in proof-

stick samples taken at intervals during boiling. If such

evidences are found, boiling temperatures should be lowered

several degrees. Generally a suitable boiling tempera

ture will be in the area, 80°-82°C.

3. With proper seeding with milled seed, temperatures

should be held in the high range, and the massecuite rds

held sufficiently high, and also the N/W, of course, so

that the supersaturation will be in the correct range.

The rds will surely be over 93 before the massecuite is

dropped, and the N/W over 3.0.

4. During boiling, the massecuite should be carefully

kept in the correct range; i.e., below the saturation at

which false grain would form.

5. The mass of crystals will increase more rapidly than at

lower temperatures, and after a certain point is reached,

the supersaturation cannot be held by increasing the rds

because of the high viscosity of the massecuite, and the

temperature must then be gradually lowered. Do not fail

to do this, as otherwise the supersaturations will become

too low for maximum crystal growth, once the most suitable

boiling consistency has been reached and is being main

tained.

6. When the pan is filled and Brixing-up is started,

watch for lowering temperatures, as if there is not abso

lute pressure control this will happen, and false grain

will form if the labile zone is entered.

VOL. 20 NO. 3 JULY 1979 291

7. The massecuite must circulate sufficiently during

boiling. If there is no mechanical stirrer, there must

be vapors of sufficient temperature in the calandrias.

This may mean an alteration of the factory's steam and

vapor distribution system, and the cost of the additional

energy could contra-indicate high-temperature boiling.

8. The crystallizer temperature pattern may well be about

the same as with lower-temperature boiling, with the same

low-point temperature.

9. If the factory has continuous raw centrifugals, the

high rds of the massecuite fed to them may cause diffi

culties with certain models.

Figure 5 shows the appearance of a typical pan tempera

ture-vacuum chart for an 80°C boiling. Note that the

temperature referred to is that of the majority of the

boiling, and not just that at which the massecuite is

dropped.


EXAMPLES OF RESULTS OF HIGH-TEMPERATURE BOILING

It is difficult to obtain statistically-significant data,

unless all other variables are correctly set, and I have

been unable to show these figures. However, use of high-

temperature boiling has resulted in some of the lowest

purity molasses in the history of certain factories.

EFFECTS OF OTHER VARIABLES

It is obvious that raising the temperature of raw boiling

is only one of numerous ways in which the molasses exhaus

tion can be made more complete, and also that it is not

applicable under all circumstances.

Following are listed some of the other factors which fre

quently are found responsible for poor performance.

1. The raw massecuite purity should be as low as possible,

and still produce a satisfactory raw sugar, which will not

recycle too much color and floe. This is the result of

the applicatxon of the principle of doing more crystalli

zation upstream in the intermediate pan. This purity

cannot be more than 20 purity poxnts higher than the molas

ses purity desired, unless precentrifuging is used.

2. The raw pan feed syrup must be free of fine crystals,

which can be made certain by heating the raw pan feed

syrup to a temperature equal to or above that carried

in the pan. Hotter feed, flashing as it enters the pan,

can enhance massecuite circulation if properly distributed

well outside the calandria center well.

3. The pans should be seeded with milled seed slurried

in isopropanol, with the correct number of seed to yield

ample crystal surface area for crystallization, and yet

not so fine that purging will be hindered.

4. False grain must not be permitted to enter at any

point. Low purity molasses and good quality raw sugar

VOL. 20 NO. 3 JULY 1979 293 cannot be obtained with badly mixed grain.

5. The viscosity of the molasses as centrifuged should be

set the same as for molasses from lower temperature boil

ings .

6. The syrup phase should be kept in the proper super-

saturation range in all of the raw crystallization units.

Using the VanHook supersaturation formulation (same N/W

in numerator and denominator) this means 1.3 - 1.45 in the

pan, receiver, and crystallizers, and a reheating to a

little over 1.0 for centrifuging.

7. Water must not be added after the massecuite has left

the pan. Condensates from pan steamout should not be

routed to the raw pan receiver. Water is by far the most

melassigenic nonsucrose substance. If the massecuite

consistency must be reduced, and it cannot be accomplished

by raising the temperature curve, use final molasses which

has been freed of fine grain and air bubbles. It mixes in

more quickly than water, and does no damage other than

slightly reducing the syrup phase supersaturation.

8. The vacuum pan should be properly equipped, prefer

ably with a mechanical circulator; with a condenser system

which permits operation by any desired pressure; with

vacuum or absolute pressure control; a meter of some type

to permit estimation of supersaturation and perhaps consis

tency; a suitable pan thermometer capable of rapid rate of

response should be located at a point of good vapor veloc

ity in the entrainment separator, so that it measures the

vapor temperature as it leaves the massecuite surface.

Measurements taken much below the top massecuite level are

subject to considerable error, and vary with the circula

tion pattern.

9. Saturation determinations should be made by the labor

atory at appropriate intervals, either with a Saturascope

or with saturation runs, so that supersaturations can be


estimated with validity.

10. If the pan does not have a mechanical circulator, there

should be sufficient vapor pressure in the calandrias to

maintain good circulation. Circulation can be accomplished

by bleeding steam or water into the boiling massecuite,

but this is very costly, energy-wise.

11. The pan receiver should be properly-sized and insula

ted, so that rapid crystallization can continue while the

massecuite is in residence there.

12. The crystallizers should have effective heat transfer

equipment and agitation. Cooling water should be control

led so that the temperature difference between the water

and the massecuite will not result in plating out crystals

on the massecuite side.

13. The interiors of the cooling elements should be cleaned

at long intervals by "boilout" or other means, to remove

microbial growths.

14. All raw crystallization equipment should be kept full

and in use at all times, growing crystals as fast as possi

ble, and this includes pans. If the pans get ahead of the

syrup supply, reduce the amount of se^d to increase grain

size.

15. Temporary high massecuite viscosities in the crystal

lizers should be relieved with raised temperatures and not

with water.

16. The massecuite that flows through the crystallizers

should be uniform.

17. All control and measuring equipment should be kept

accurately calibrated and in use at all times.

VOL. 20 NO. 3 JULY 1979 295

If a Stevens mingler is used, keep the upper hopper full

to obtain more crystallization before the massecuite

reaches the heating coils.

I hope I have gotten across the points that increased boil

ing temperatures is only one of many ways to increase

molasses exhaustion, and may not be indicated for certain

factories because of shortage of steam, or centrifugal

requirements, but if not prevented by these factors, and

for those very short of crystallizer capacity, the tech

nique can and has proved profitable.

LITERATURE CITED

(1) Eis, F. G. Personal communication.

(2) Karadzik, V. and L. Terek. 1977. Sugar J., 40 (5), (1977) Oct. pp. 29-31.

(3) Kukharenko. 1953. Quoted by Hirschmuller in P. Honig, ed., "Principles of Sugar Technology," Elsevier, Amsterdam, V. 1., pp. 24-25.

(4) M c G m n i s , R. A., P. W. Alston, S. Moore. 1942. Ind. Eng. Chem., 3± (Feb.) (1942), pp. 171-173, quoted by de Bruyn in Honig, V. 2, p. 464.

(5) Susie, S. K. 1972. "Studija o Problemu Kristalizaci je Saharoze iz necistih Rastvora," Gradevinska Knija, Belgrade (1972), pp. 99-100.

The Effect of Soil Residues of Atrazine on Sugarbeets (Beta vulgaris L.)*

R. L. ZlMDAHL, S. M. GWYNN. AND K. Z. HAUFLER

Received for publication February 1, 1979

77

31

24

11

45

36

12

24

40

0.6

2.0

2.2

(meq/lOOg)

7.8

15.8

30.5

VOL. 20 NO. 3 JULY 1979 299 Table 1

Soils used for atrazine bioassay study.

Soil textural class sand silt clay O.M. CEC

Sandy loam

Loam

Clay loam

Treated soil was stored dry in covered glass jars until

needed. Seven ounce styrofoam drinking cups, with holes

in the bottom for drainage, were used as pots. After soil

was added to the cups they were placed in a large tray in

a randomized block design with five replicates and

sub-irrigated until completely wet. Great Western Mono-Hy

D-2 sugarbeet seeds were prepared for planting by wrapping

them in paper towels and soaking them under cold, running

water for about one hour. The seeds were then transferred

to a dry paper towel and allowed to air-dry for about 15

minutes. The partially dried seeds were treated with

thiram (tetramethy1thioramidisulfide) by shaking in a

small plastic bag. Ten or more seeds were planted per

cup, and the surface of each cup was then covered with

styrofoam beads to reduce moisture loss. After emergence

plants were thinned to five per cup. Earlier experiments

had shown that length of the first true leaf (blade and

petiole) was a reliable growth measurement to predict

atrazine presence. Sugarbeets were grown 18 days in Heldt

and Ascalon soil, but it took 29 days to reach the same

growth stage in Weld soil. At these times the length of

the first true leaves for five plants per pot was measured.

FIELD STUDIES

To relate the effect of atrazine on sugarbeet growth in

the greenhouse to that observed in the field, a two-year

field experiment was performed. Corn was planted on May

15, 1975 in a randomized block with four replications.


Atrazine was applied preemergence four days later at rates

of 2.0, 1.0, 0.5, 0.25, 0.125 and 0 lb ai/A. All plots

were hoed several times during the growing season to control

annual and perennial weeds. In October, the center two rows

of corn were hand harvested from each plot. Fresh and dry

weights were recorded and yield of corn silage was calcu-

lated in tons per acre.

In April, 1976, after plowing to about 10 inches, Mono-Hy

D-2 sugarbeet seeds were planted in the same plots. After

emergence sugarbeets were thinned to one plant per foot of

row. Sprinkler irrigation was used and hand weeding

employed as necessary in all plots to prevent excessive

weed competition. Visual injury ratings were made during

the season. In October, the center two rows of sugarbeets

in each plot were harvested. Roots were topped, washed,

weighed, and two random samples of 15 roots were analyzed

for purity and sucrose.

CHEMICAL STUDIES

To determine total residual concentrations of atrazine

present in soil at the time sugarbeets were grown, soil

samples were chemically analyzed. Soil samples from each

plot were taken in May, 1975 soon after initial atrazine

treatment. Samples were taken again at corn harvest

(October, 1975), after sugarbeets were planted (April,

1976) and following sugarbeet harvest (October, 1976). All

samples were frozen for later extraction and analysis.

Atrazine was extracted from soil by refluxing 50 g for one

hr in 90% acetonitrile/water (v/v). The extract was added

to a separatory funnel and extracted with two 25 ml portions

of methylene chloride, which were combined, dried, and

transferred to an alumina column for clean up. After

elution with benzene-ether (60:40) samples were brought

to an appropriate volume in benzene for analysis.

Atrazine was detected using an electron capture gas

VOL. 20 N O . 3 JULY 1979 301

chromatograph and a Dohrmann-Envirotech halogen specific

microcoulometer. Analysis with electron capture showed

that atrazine could be detected with a linear range of

1-10 nanograms (Ng). However, even after sample clean up,

many impurity peaks resulted, so only the microcoulometer

was used. Operating conditions were:

Injection port temperature 215°C

Column 200°C

Transfer section 280°C

Combustion oven 800°C

Outlet section 720°C

Argon flow rate 40 ml/min

Oxygen flow rate 100 ml/min

A 30 cm long 2 mm ID glass column was packed with 5% SE-30

on 60/80 mesh gas-chrom Q. On low gain with a range of 300

ohms the linear range of detection was 10 to 100 Ng.

Injection volumes from 2 to 10 μ1 were used.


BI0ASSAY STUDIES

An atrazine concentration of 0.2 ppmw or higher killed

sugarbeets, while 0.1 ppmw atrazine seriously affected

sugarbeet growth in all three soil types (Table 2 ) . Data

are expressed as percent of the untreated control rather

than length of the first true leaf and represent the average

of several experiments conducted in each soil type. Curves

showing percentage of control growth vs. applied atrazine

concentration were drawn for each soil. From the regression

equations obtained for these curves, the percentage decrease

in sugarbeet growth for any applied atrazine concentration

was calculated (Table 3 ) . Although these data are impor-

tant, they have little practical value except as a general

guideline, as they are based on the quantity of atrazine

applied rather than on the amount which is available to

affect sugarbeet growth. The relationship between the two

has not been determined. Nevertheless, it Is significant

that growth was suppressed 50% in all three soils at


Table 2 Growth of sugar-beets in the greenhouse in three soils treated with atrazine.

Atrazine concentration Growth as % of untreated controla

in soil (ppmw) sandy loam loam clay loam

0 100a 100a 100a

0.0031 89b 56b 119a

0.0063 83b 58b 92a

0.0125 82b 55b 82b

0.025 84b 20c 30c

0.05 68c 16c l1d

0.1 17d 5d 2d

0.2 0 0 0

0.4 0 0 0

0.6 0 0 0 a Values in one column followed by the same letter are not significantly different at the 1% level of probability according to Duncan's multiple range test.

Table 3

Calculated concentration of atrazine required to decrease sugarbeet growth in greenhouse bioassay studies.

Soil Growth suppression Atrazine

(%) (ppmw)

Sandy loam 10 .0050

25 .0150

50 .0590

Loam 10 .0148

25 .0184

50 .0272

Clay loam 10 .0063

25 .0087

50 .0163

V O L . 20 N O . 3 JULY 1979 303

atrazine concentrations of 0.059 ppmw or less and that

there was a difference between soils. Fifty percent growth

suppression occurred at 0.059, 0.0272 and 0.0163 ppmw in

sandy loam, loam, and clay loam soil, respectively. This

relationship is not surprising given the well documented

adsorptive characteristics of soils with higher amounts of

clay and organic matter which decrease herbicide effects.

Reflective of greater variability and the lack of precision

in measuring small amounts the same consistency between

soils was not shown for 10 and 25% growth suppression.

FIELD STUDIES

Corn yields from each atrazine treatment and the untreated

plots were not significantly different (Table 4 ) . As

determined by visual injury ratings, there was slight dam-

age to sugarbeets in plots treated with the lowest three

rates of atrazine and extensive damage in plots treated

with 1.0 and 2.0 lb ai/A. Atrazine applied at 1 or 2

lb ai/A decreased sugarbeet yield but did not affect

percent sucrose or purity. Root yields from plots treated

with 0.25 and 0.5 lb ai/A were not different from the

control while a slight and unexplained increase over the

control weight was found for 0.125 lb ai/A atrazine.

The two highest rates decreased yield more than 50%.

CHEMICAL STUDIES

Chemical analysis is necessary to relate the amount of

atrazine applied in the bioassay and in field plots. The

data in Tables 2 and 3 show that extremely small quantities

of atrazine greatly decrease growth of sugarbeets in

bioassay studies. The two highest rates of applied atra-

zine reduced sugarbeet yield in the field (Table 4 ) .

The limit of chemical detection capability using the

microcoulometer was 0.1 ppmw of atrazine present in soil.

Lower levels of atrazine can be detected by extracting

larger amounts of soil and by employing extraordinary

analytical care. These measures were beyond the scope

of the present study. Without extensive clean-up and

analytical techniques beyond our capability, we could not

detect atrazine levels at or below 0.05 ppmw or approxi-

mately 10 Ng in 50 g of soil. Eberle and Gerber (2)

chemically detected 0.04 ppm of ametryn, and biologically

detected 0.2 ppm with tame oats and 0.02 ppm with Chorella

pyrenoidosa. Thus, their chemical sensitivity was about

equal to ours but their bioassay species were not as

sensitive. In sugarbeet bioassay studies the median con-

centration was 0.05 ppmw and four concentrations were lower.

Thus, the minimum detectable concentration was 0.1 ppmw.

No atrazine was detected in these samples, but it was

detected in soil treated with 0.1 to 0.6 ppmw. If the

concentrations of atrazine applied in the field are con-

verted to ppm, with the assumption that initially applied

atrazine was uniformly distributed throughout the top three

inches of soil, one can calculate that ppm approximately

equals lb ai/A. The three lowest concentrations applied

in the field should have been detectable with our analytical

method but were not. Because the field was plowed in the

fall of 1975, atrazine was distributed through the top 10

inches of soil and further diluted. In addition, 50% or


Table 4

The affect of atrazine on corn yield and sugarbeet yield.

V O L . 20 N O . 3 JULY 1979 305

more of the atrazine applied in 1975 would have been de-

graded by the time the sugarbeet crop was planted in 1976,

further reducing the likelihood of detecting the lowest

concentrations (3). Thus, the three lowest concentrations

could not be detected.

We concluded from the greenhouse and field studies

that sugarbeets are extremely sensitive to low residues

of atrazine. Our results also indicate that the sugarbeet

is a more sensitive analytical tool than the microcou1ometer

for detecting low levels of atrazine but perhaps not for

precise quantification. We were unable to develop a

correlation between chemical and biological analyses

because the sugarbeet plant was surprisingly more sensitive

to low soil residues of atrazine than suspected and gas

chromatographic analysis was not sensitive enough to detect

atrazine levels that the sugarbeet could. Any amount of

atrazine detected by chemical assay should alert a grower

to the distinct possibility of sugarbeet injury.

SUMMARY

A study was conducted to determine levels of residual

atrazine in soil that injure succeeding crops of sugarbeets

and to correlate the results of biological and chemical

assays. Concentrations of 0.2 ppm or higher killed sugar-

beets while 0.1 ppmw seriously affected sugarbeet growth in

three soil types. Sugarbeets are a more sensitive

analytical tool than gas-liquid chromatography with

detection by microcou1ometry. Because of this sensitivity

to low soil residues of atrazine, correlation between

biological and chemical assay was not possible. Any

amount of atrazine detected by chemical assay should alert

a grower to the distinct possibility of sugarbeet injury.

ACKNOWLEDGEMENT

The authors express their appreciation to the Grower-Great

Western Sugar Company Joint Research Committee, Inc. for

partial financial support.


LITERATURE CITED

(1) Behrens, R. 1970. Quantitative determination of triazine herbicides in soils by bioassay. In Residue Reviews 32: 355-369.

(2) Eberle, D. 0. and H. R. Gerber. 1976. Comparative studies of instrumental and bioassay methods for the analysis of herbicide residues. Archives of Env. Cont. and Tox. 4: 101-118.

(3) Frank, R. 1966. Atrazine carryover in production of sugar-beets in Southwestern Ontario. Weed Sci. 14: 82-85.

(4) Zimdahl, R. L., V. H. Freed, M. L. Montgomery and W. R. Furtick. 1970. The degradation of triazine and uracil herbicides in soil. Weed Res. 10: 18-26.

The Effect of Root Dehydration on the Storage Performance of a Sugarbeet Genotype Resistant

to Storage Rot W. M. BUGBEE AND D. F. COLE

Received for publication February 14, 1979 ABSTRACT

The sugarbeet cultivar American Crystal 2 hybrid B

(2B) was superior to the storage-rot-resistant genotype

75P6 in the production of recoverable white sugar per

ton (RWST) at harvest, but 75P6 was superior to 2B after

the roots had been inoculated with Phoma betae, Botrytis

cinerea, and Penicillium claviforme and stored at 10° C

in 98% relative humidity for 106 days. The amount of rot

in 75P6 was 50% of that in 2B when roots had lost 8-10%

of their weight in storage. Dehydrated roots had lower

clear juice purity (CJP) and RWST than did turgid roots.

Severely dehydrated roots (24% weight loss) of both

genotypes did not develop more rot than turgid roots

(9% weight loss), but there was a decrease in pol sucrose,

CJP, and RWST.

INTRODUCTION

Moisture loss from sugarbeet roots because of drought

during the growing season or because of exposure to

drying conditions after harvest reportely causes the

*Plant Pathologist and Plant Physiologist, U. S. Department of Agriculture, Science and Education Admin-istration, Agricultural Research, North Dakota State University, Fargo 58105. Cooperative investigations of the U. S. Department of Agriculture and North Dakota Agricultural Experiment Station. Published with approval of the Director of the North Dakota Agricultural Experiment Station as Journal Article No. 960.

Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U. S. Department of Agriculture, and does not imply its approval to the exclusion of other products that may not also be suitable.


roots to become more susceptible to storage rot. A 9-fold

increase in rot during 19 weeks of storage at 10° C was

reported for roots that had a 15% weight loss before

storage began (5). Another report showed that when roots

with a 19% weight loss were injured, there was a 10-fold

increase in storage rot compared with a 7-fold increase

in uninjured roots (7). Greater rot in the injured roots

was attributed, in part, to reduced wound repair capa

bility in wilted roots. Exposure of root sections to

drying for 24 hrs increased susceptibility to Phoma betae,

and this susceptibility increased more rapidly on wilted

sections than on nonwilted sections above 10° C (2).

Stored roots rotted more if irrigation during the growing

period was restricted, and the benefit of fertilization

was nullified when roots were produced under drought

conditions (8) . Most of the rot was caused by P. betae.

Results from the U.S.S.R. further show that cultivars

resistant to storage rot maintain higher leaf and root

turgor than susceptible roots under drought conditions.

There might be a genetic link between drought resistance

and storage-rot resistance (9).

The Red River Valley of North Dakota and Minnesota

is the largest sugarbeet area in the U.S., and nearly

all of that area is cultivated as dryland. Our objective

was to determine the effect of water loss from stored

roots on rot caused by the major storage pathogens in

that region and to see if genetic resistance to rot

would reduce sucrose losses under moisture stress.


Two sugarbeet (Beta vulgaris L.) genotypes were

grown for 160 days at the North Dakota Agricultural

Experiment Station, Fargo. One genotype was a commercial

cultivar, American Crystal 2 hybrid B (2B), and the other

was a breeding line, 75P6. Cultivar 2B is susceptible

to the storage rot pathogens used here. Line 75P6 was

developed at Fargo from the U.S.S.R. introduction VNIS

F526 by interpollinating six roots that were selected for

resistance to storage rot caused by Phoma betae (Oud.)

VOL. 20 NO. 3 JULY 1979 309

Frank. This line also responded with moderate resistance

to storage rot caused by Botrytis cinerea L. and

Penicillium claviforme Bainier.

Roots were harvested, washed, and divided into four

groups of 10 roots each for each of the two genotypes.

The roots of group 1 were inoculated and stored in

perforated plastic bags. Group 2 roots were stored

identically as group 1 but not inoculated. Group 3 was

inoculated and stored in open-mesh onion sacks. Group 4

was stored identically as group 3 but not inoculated.

The eight treatments were replicated 16 times in a

complete randomized block design. Storage was at 10-2° C

for 106 days. Relative humidity of circulated air in

the storeroom was about 85%, and near 100% within the

perforated plastic bags.

Inoculation was done by inserting, with a twisting

motion, an 11-mm d cork borer 8-10 mm into the root.

The end of the borer had a serrated edge to increase

wounding action and was dipped into inoculum before

wounding each root. The inoculum consisted of a mixture

of conidia from P. betae, P. claviforme Bainier, and B.

cinerea L. suspended in a 0.1% water agar.

All inoculated roots were given a rot index based

on the distance rot had progressed in both directions

from the circular wound site: 0, no rot evident; 1, rot

up to 2 mm; 2, rot up to 5 mm; 3, rot up to 10 mm; 4,

rot up to 30 mm; 5 rot up to 40 mm (Fig. 1 ) . Rot also

was measured by excising the rotted portions from the

inoculation site, weighing the rotted tissue, and

expressing rot as a percentage of the final weight of

the entire root sample. This was done on five randomly

selected roots from each bag and the other five roots

were used for quality measurements.

Sucrose was measured with a polarimeter by the cold

digestion method (3) and adjusted for root weight loss

after storage. Clear juice purity (CJP) was determined

by using the method described by Dexter and co-workers

(4). The data were summarized and statistically analyzed

using the SAS-76 computer program (1) on an IBM 370/148

310 c o m p u t e r .

JOURNAL OF THE A.S.S.B.T.

F i g . 1 . - — D i a g r a m o f r o t r e p r e s e n t e d b y t h e s h a d e d a r e a i n r e l a t i o n t o t h e w o u n d s i t e r e p r e s e n t e d b y t h e b r o k e n - l i n e c i r c l e , a n d t h e r o t i n d e x n u m b e r a s s i g n e d t o e a c h c l a s s .

RESULTS

R o o t s t h a t w e r e s t o r e d a t 1 0 ° C i n 98% r e l a t i v e

h u m i d i t y i n p e r f o r a t e d p l a s t i c b a g s f o r 106 d a y s l o s t

8 - 10% o f t h e i r o r i g i n a l w e i g h t ( T a b l e 1 ) . T h o s e s t o r e d

Table 1. --The effect of root dehydration during 106 days of storage at 10° C on weight loss and storage rot of a storage-rot susceptible (2B) and resistant (75P6) genotype

Noninoculated Inoculated storage storage

Relative humidity,% Relative humidity, % Genotype 98 85 98 85

Weight loss, % 75P6 8 d* 23 a 9 cd 24 a 2B 10 c 22 b 10 c 24 a

Rot by weight, %

75P6 2.1 c 2.5 bc

2B 5.2 a 4.0 ab

Rot index

75P6 2.4 b 2.8 b 2B 4.8 a 4.8 a

* Means of 16 replications; means followed by the same letter within each parameter are not significantly (P = 0.05) different by Duncan's multiple range test.

VOL. 20 NO. 3 JULY 1979 311 a t t h e same t e m p e r a t u r e in open-mesh sacks and exposed to c i r c u l a t i n g a i r t h a t c o n t a i n e d 85% r e l a t i v e h u m i d i t y l o s t 20 - 24% of t h e i r o r i g i n a l w e i g h t .

The amount of s t o r a g e r o t in 75P6 was l e s s than 50% of t h a t in 2B (Table 1 ) . The amount of r o t w i t h i n each geno type was n o t a f f e c t e d by t h e amount of we igh t l o s s d u r i n g s t o r a g e . A compar i son of t h e two methods of measu r ing r o t showed a p o s i t i v e c o r r e l a t i o n ( r = . 6 9 * * ) .

C u l t i v a r 2B was s u p e r i o r to 75P6 in p e r c e n t a g e s u c r o s e , CJP, and r e c o v e r a b l e w h i t e s u g a r p e r t o n (RWST) a t h a r v e s t (Table 2 ) . N o n i n o c u l a t e d r o o t s of 2B were

T a b l e 2 . — Q u a l i t y m e a s u r e m e n t s a t h a r v e s t o f a s t o r a g e - r o t r e s i s t a n t ( 7 5 P 6 ) a n d s u s c e p t i b l e ( A m e r i c a n C r y s t a l 2 h y b r i d B ) g e n o t y p e

S u c r o s e C l e a r j u i c e R e c o v e r a b l e w h i t e

G e n o t y p e c o n t e n t p u r i t y s u g a r / t o n

% % l b s K g / t

2B 1 4 . 8 2 a* 9 3 . 8 4 a 2 5 9 a 1 2 8 a 7 5 P 6 1 3 . 9 1 b 9 1 . 2 0 b 2 2 9 b 1 1 3 b

* Means of 16 replications; means followed by the same letter within each column are not significantly different (P = 0.05) by the Waller-Duncan K-ratio method of mean separation.

superior to roots of 75P6 in quality after storage of

106 days at 98% relative humidity (Table 3 ) .

Genotype 75P6 was superior to 2B in all quality

measurements after the roots were inoculated and stored

at 98% relative humidity (Table 3 ) . At harvest. 2B

produced 24 lbs more RWST (11.9 Kg/t) than 75P6 but when

infected with storage rot pathogens and stored at 98%

relative humidity, 75P6 produced 35 lbs more RWST (17.3

Kg/t) than 2B (Tables 2 and 3 ) . When inoculated and

stored under low humidity, the RWST for both genotypes

was similar.

DISCUSSION

Genotype 75P6, which has resistance to the storage

rot pathogens tested here, expressed this characteristic

312 JOURNAL OF THE A.S.S.B.T. Table 3. — T h e effect of root dehydration and storage rot on

the quality of a storage-rot susceptible (2B) and resistant (75P6) genotype during 106 days of storage at 10° C

Noninoculated Inoculated Storage Storage

Relative humidity, % Relative humidity, % Genotype 98 85 98 85

Sucrose content, % 75P6 13.77 b* 13.29 bc 14.23 ab 11.79 d

2B 14.93 a 13.98 b 12.76 c 12.46 cd

Purity, %

7 5 P 6 8 8 . 3 7 a b 8 4 . 4 0 c 8 9 . 4 2 a 7 9 . 3 0 d

2B 9 0 . 9 9 a 8 8 . 0 3 ab 8 5 . 8 9 bc 8 0 . 3 6 d

R e c o v e r a b l e w h i t e s u g a r / t o n , l b s ( K g / t )

7 5 P 6 2 1 1 b 1 8 0 c 223 ab 1 3 0 d ( 1 0 4 ) (89 ) ( 1 1 0 ) ( 6 4 )

2B 2 4 4 a 2 1 3 b 1 8 0 c 1 4 5 d ( 1 2 1 ) ( 1 0 5 ) ( 8 9 ) ( 7 1 )

* M e a n s o f 1 6 r e p l i c a t i o n s ; m e a n s f o l l o w e d b y t h e s a m e l e t t e r w i t h i n e a c h p a r a m e t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t ( P = 0 . 0 5 ) b y t h e W a l l e r - D u n c a n K - r a t i o m e t h o d o f m e a n s e p a r a t i o n .

f a v o r a b l y n o t on ly w i t h l e s s r o t t han t h e s u s c e p t i b l e c u l t i v a r 2B , b u t a l s o in e s s e n t i a l l y no l o s s of RWST when i n o c u l a t e d and s t o r e d i n h i g h h u m i d i t y . C o n v e r s e l y , t h e s u s c e p t i b l e c u l t i v a r l o s t 58 pounds of RWST (28.7 Kg/ t ) d u r i n g s t o r a g e . Thus , a t h a r v e s t , c u l t i v a r 2B was s u p e r i o r to 75P6 in y i e l d of RWST bu t i n f e r i o r to 75P6 when i n o c u l a t e d and s t o r e d in h igh h u m i d i t y . Both geno-t y p e s s u f f e r e d a s i g n i f i c a n t l o s s of 66 - 76 l b s of RWST (32.7 - 37.6 Kg/ t ) when i n f e c t e d and s t o r e d a t t h e lower h u m i d i t y . The a d v a n t a g e o f t h e g e n e t i c r e s i s t a n c e p o s s e s s e d by 75P6 was l o s t when t h e s e r o o t s were de-h y d r a t e d . We r e p o r t h e r e fo r t h e f i r s t t ime t h a t a b r e e d i n g l i n e p o s s e s s i n g g e n e t i c r e s i s t a n c e t o P . b e t a e , B. c i n e r e a , and P . c l a v i f o r m e w i l l s u f f e r a l o s s in r e c o v e r a b l e s u c r o s e comparable t o a s t o r a g e r o t s u s c e p t i b l e c u l t i v a r i f t h e r o o t s a r e a l lowed t o l o s e more t han 10% of t h e i r we igh t t h rough w a t e r l o s s d u r i n g s t o r a g e .

The q u a l i t y d e t e r i o r a t i o n o f d e h y d r a t e d r o o t s d u r i n g s t o r a g e r e p o r t e d h e r e a g r e e s w i t h o t h e r s ( 2 , 5 , 7 , 8 , 9 ) ,

VOL. 20 NO. 3 JULY 1979 313 but our results show that these losses may not be

accompanied by increased rot.

Dehydrated and infected roots of 75P6 did not suffer

an increased rot relative to the turgid roots. In fact,

there was no change in rot development within each

genotype whether dehydrated or turgid. There was a

significant decrease during storage in RWST, purity,

and pol sucrose in dehydrated, infected 75P6. Moisture

loss, coupled with infected tissue, may have caused a

sufficient increase in respiration in 75P6 to account

for the decrease in sucrose content. There is a general

phenomenon that infected resistant plant tissue respires

at a higher rate than infected susceptible tissue (6).

Therefore, the prevention of root dehydration during

storage was more important for the rot-resistant genotype

than it was for the susceptible cultivar.

LITERATURE CITED

(1) Barr, A. J., J. H. Goodnight, J. P. Sail, and J. T. Ilellwig. A user's guide to SAS 76. SAS Institute Inc., Raleigh, NC 27605.

(2) Cormack, M. W., and J. E. Moffatt. 1961. Factors influencing storage decay of sugar beets by Phoma betae and other fungi. Phytopathology 51:3-5.

(3) DeWalley, H. C. S. 1964. Methods of sugar analysis. Elsevier Publishing Co., Amsterdam, Holland, 153 pp.

(4) Dexter, S. T., M. G. Frakes, and F. w. Snyder. 1967. A rapid and practical method of determining extract-able white sugar as may be applied to the evaluation of agronomic practices and grower deliveries in the sugar beet industry. J. Am. Soc. Sugar Beet Technol. 14:433-454.

(5) Gaskill, J. O. 1950. Drying after harvest increases storage decay of sugar-beet roots. Phytopathology 40:483-486.

(6) Goodman, R. N., Z. Kiraly, and M. Zaitlin. 1967. The biochemistry and physiology of infectious plant disease. Princeton, NJ: D. Van Nostrand Co. (p.84).

(7) Kornienko, A. S. 1975. Prophylaxis of storage rot. (In Russian). Zashchhita Rastenii (Moscow) 6:21. (Translated).

JOURNAL OF THE A.S.S.B.T. (S) Larmer, F. G. 1937. Keeping quality of sugar beets

as influenced by growth and nutritional factors. J. Agr. Res. 54:185-198.

(9) Shevchenko, V. N., and Yu. S. Toporovskaya. 1975. Significance of turgor to manifestation of genetic properties of resistance to storage rot in sugar beets. (In Russian). In Effektivnye priyemy i sposoby bor'by s boleznyami Sakharnoy Svekly, pp. 20-24, Moscow. (Translated).

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