Digital Re-print - March | April 2013

Additives for flour standardisation - Part I: Enzymes

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Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

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In biological systems, all the conversion processes can take place quickly at relatively low temperatures and

mild chemical conditions, because enzymes help to run the reactions with lower energy input.

Because of the ability to perform very complex reactions under these mild condi-tions, enzymes are produced in industrial scale, mostly by micro-organisms. The devel-opment of new enzymes in short succession all around the world is fueled by increasing competition. High quality and low cost prod-ucts manufactured with the help of these enzymes have the chance to compete better in the market.

Enzymes are used in many areas of the food industry. In contrast to most other food application, enzymes used in the flour indus-try do not show their effects at the moment they are added, that is, right in the mill. In order to see the effect of enzymes in flour, the baker must add water. This problem of time and place is the general challenge in the flour improvement business, but it gets even more complex when it comes to enzymes. But enzymes also have definite advantages as they are specialised on distinct effects, used in very small dosages, natural and completely deactivated under baking conditions.

As with all the concentrated natural sub-stances, enzymes pose the risk to cause aller-

gic reactions. Therefore, it is advised that the employees in contact with enzymes should wear gloves, mask and goggles. Although with a lower probability because of the dilution in flour or bread improvers, the same risk is present for bakers. Therefore, enzyme producers are trying to manufacture preparations that emit less dust.

For a long time, α- and ß-amylase were thought to be the only enzymes that could be used in the milling industry. This view has changed dramatically since the introduction of hemicellulases two decades ago, and has now received another blow through the success of lipolytic enzymes. There are many more enzymes (Table 1) that still play niche roles for certain applications, but which may turn out one day to be as versatile as the afore-mentioned types.

AmylasesThe most used

types of amylases in flour industry are alpha-amylase, beta-amylase and amyloglucosidase (glucoamylase). Like

most enzymes, amylases also act on sub-stances that are well in contact with water. Alpha-amylase breaks down unbranched moieties of starch molecules, releasing dex-trins. These dextrins act as substrate for beta-amylase and glucoamylase, which in turn produce sugars like maltose and glucose that can be directly used by yeast. By the action of amylases, the dough viscosity is decreased (water released from the starch), the fermentation power and the volume are increased, taste and colour are improved, the crumb softness is retained and the shelf life is extended.

Additives for flour standardisation -

Part I: Enzymesby Lutz Popper, Mühlenchemie GmbH & Co. KG, Germany

Figure 1: Enzyme production scheme

Grain&feed millinG technoloGy18 | march - april 2013

FEATURE

Innovations for a better world.

Leave nothing to chance. With WinCos Care, the Service Management System

of Bühler, you will put your maintenance work in order. The system, which is

customized by Bühler to precisely fit the specific needs of your production system,

takes charge of the entire planning and administration of all your maintenance

jobs. This ensures efficient processes and maximum plant uptime.

WinCos Care Service

Management System –

Unrivaled Efficiency.

Maximum uptime:

Prefabricated job cards are based

on service hours or calendar intervals

as well as individual job planning.

Plug & Play:

Efficient processes and customer-

specifically programmed software for

all plants.

Always up to the minute:

Automatic online updates and data

backup.

All in one system:

Extensive documentation, among

other things for certifications

(e.g. International Food Standard).

Bühler AG, Grain Processing Customer Service, CH-9240 Uzwil, Switzerland,

T +41 71 955 30 40, service.gp@buhlergroup.com, www.buhlergroup.com

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Enzyme active malt flourSeeds need enzymes to start with their vital

activities, therefore high amount of enzymes are produced during the germination step. Grains to be used for enzymatic purposes will be germinated before processing. Enzyme-active malt flour is produced from germinated barley, wheat or rye. The functions of these products are generally similar.

Besides alpha- and beta-amylases, there are other enzymes in malt flour, like pro-teases and glucanases. While some of these have positive effects on baking, some do the opposite. Like the enzymes natively found in flour, enzymes from malt flour also have a considerable effect on the Falling Number (FN). If the enzymatic activity of flour is very low, malt flour up to 150 grams per 100 kg can be used in order to decrease FN values to 250-300 seconds. In the case of FN below 300 s, enzyme active malt flour may result in sticky doughs even when used at below 50 g per 100 kg. The activity of malt flour is mostly stated as the diastatic power (DP) and is usually at around 400 DP. This activity may be interpreted as 80-120 SKB/g.

Fungal amylaseUsually fungi belonging to Aspergillus

genus are used to produce fungal amylase. The species are well defined and do not produce toxic or carcinogenic substances. The fungi are grown in large fermentation tanks end left producing and excreting the desired enzymes to the fermentation fluid. The fermentation broth containing the raw enzyme is processed by centrifugation, filtra-tion, precipitation, ultrafiltration and the like to result in a purified concentrated enzyme solution. This concentrate is converted to powder by spray drying, mixed with bulk material to standardise the activity and free flowing agents to provide ease of usage in mills. As a dry powder most enzymes are very stable and can be kept for years without losing much activity. Figure 1 provides a scheme for the production of enzymes from plants, animals and microbes.

Amylase from fungal sources is mostly alpha-amylase. Most detrimental side activi-ties are prevented by selection of suitable subspecies and processing conditions. At normal dosage, fungal amylase does not interfere with FN values because it is not stable at the temperature (approx. 95 °C) of the standard assay. There is another, modi-fied FN test to determine the effect of fungal amylase, which employs lower maximum temperatures at around 82 °C.

The dos-age of alpha-amylase preparations depends on their activ-ity. In order to express the activ-ity of alpha-amylase, the unit for the test method developed by Sandstedt, Kneen and Blish (1939), the SKB, is used. Even though differ-ent suppliers use different test methods, the results are often converted into SKB. For wheat with Falling Numbers between 300 and 350 s, the typical dosage is adjusted as 500 SKB per kg of flour (that is, 1

gram of a 50,000 SKB/g amylase per 100 kg of flour). There is much less native enzyme in flour with Falling Numbers above 400 seconds, therefore 3 grams or more of the same amylase may be used. On the other hand, in flours with very low FN values, using trace amounts of amylase (like 0.1-0.2 grams of 50,000 SKB/g amylase) will not affect the FN but may have a beneficial effect on the dough properties and volume yield.

GlucoamylaseAlso called amyloglucosidase or previ-

ously gamma amylase, this enzyme breaks starch to its smallest building blocks, glucose. It also can work on the branching points of amylopectin, as opposed to alpha-amylase. With this property, glucoamylase helps improving the browning of baked products and stabilises the fermentation in prolonged fermentation processes. There is no viscos-ity lowering effect of this enzyme because it leaves the large starch molecules basically unaffected, at least within the relatively short time of baking processes.

HemicellulaseThe term hemicellulase designates

a family of enzymes. All the members shown in Figure 2 are able to break down the pentosans (therefore they are also called pentosanases), but their

Figure 2: Hemicellulolytic enzymes Kopie

Grain&feed millinG technoloGy march - april 2013 | 19

FEATURE

is sensitive machinery, motors or anything electric and adversely affected by water.

The technology, which is the first of its kind in the UK, uses a continuous flow heating coil system to heat water to such a high degree that it becomes extremely hot vapour. The emitted dry steam contains minimal moisture and efficient cleaning capa-bility is produced from the steam pressure made on the surface area.

Is all steam cleaning the same?So steam is simply steam? Well actually,

no. Steam can be produced in a range of different grades, each matching dif-ferent industry applications. Picking the cleaning method best suited to your operation depends upon a number of options including the nature of the sur-face to be cleaned and the type of material or residue found on crushing or milling appa-ratus, conveyors and elevator pits and silos.

To date, conventional CIP systems have tended to rely on traditional boiler systems which are only required to heat the water to a maximum of 75 degrees and rely on high water flow and minimal pressure, using a lot of water in the process.

Most food related sites use hot water that comes off the boiler through hoses, using foamers, liquid chemicals and other sanitation agents. They can use between 200-1,000 litres of water per hour to blast a surface clean. They can also have the nega-tive side effect of sending dangerous bacteria airborne, spreading them through the plant without killing them. This ‘wet steam’ system does not use a vapour process.

Benefits of dry steam cleaning Efficient cleaning capacity is produced

from the steam pressure made on the surface to be cleaned and the solvent power of micro drops at a high temperature, with minimal moisture present.

The continuous steam system provides constant steam quality which can be adjusted by volume and dryness. Water flow and heating power can be controlled and adapt-ed by an electronic control system.

The amount of water saved depends upon the flow rate of the water system and the pressure employed, but it can save up to 90 percent of water used. OspreyDeepclean’s dry steam technology will typically use between 10-30 litres of water per hour, whereas a conventional system will use between 200-1,000 litres per hour.

Conventional cleaning leaves the risk of potentially dangerous residues contaminating food and raw materials. Then you also have the issue of getting into difficult spaces, such as tight crevices in storage areas or complex shaped equipment.

Dry steam sanitises surfaces, penetrating cracks, crevices and other hard-to-reach areas where manual and traditional cleaning methods, which mainly rely on potentially hazardous chemicals, fail to achieve the required standards.

As well as being applicable to a wide range of work settings, steam can be used to undertake innumerable cleaning tasks. The system can be used on feeding, mixing and blending vessels, machinery, conveyor belts, rollers, pipelines and also general floor areas, storage spaces and much more. As it is applied to the surface, dry steam leaves very little residue and can almost touch dry, especially when compared

to any other clean-ing method.

No additional ingredients are required in the steam to improve cleaning power, as efficient cleaning capacity is produced from the steam pressure made on the surface to be cleaned and the solvent power of micro drops at a high temperature, with minimal moisture present. However, where specific tasks or loca-tions demand it, ingredients can be added to improve the solidifica-tion of specific substances, for instance within liquid fat appli-cation devices which could congeal with-out the use of additional ingre-dients.

Dry steam machines for different applications

The tech-nology Osprey Deepclean has developed is available in a range of dry steam machines for different applications, based on many years’ experi-ence of creating bespoke steam solutions. This

includes the fully auditable dry steam belt sanitation unit (BSU) which cleans conveyor belts to allergen level, saving up to 3 million litres of water per annum.

The organisation has also developed a central steam system for food production and packaging areas. This is much like a central vacuum, which facilitates cleaning by simply plugging the steam hoses into central steam pipes without the need for handling cleaning machines. The sophisti-

cated equipment can be used for the cleaning of heavy parts and for plastic parts cleaning. The machines start from a 3kW single phase unit and

reach up to 144kW units avail-able in electric, oil or

gas heated coils.

Grain&feed millinG technoloGy march - april 2013 | 11

FEATURE

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impacts on dough and baking properties vary widely.

It is assumed that pentosans form a network with gluten; the more pentosans are involved, the firmer the network. Because they bind large amounts of water (approximately 10 times their dry weight), they reduce the availability of water for the gluten reducing its expandability. Additionally, pentosans can be cross-linked to each other by the so-called oxidative gelation, increasing their ability to bind water further.

That is a main reason why darker wheat flours and mixtures containing rye flour have a lower volume yield than white flours. The volume yield of all flours can be increased considerably by adding hemicellulases.

Many of these enzymes are derived from Aspergillus strains selected for or specialising in the production of hemicel-lulases.

Hemicellulases are often sold in com-pounds with amylase and other enzymes. The most common hemicellulase for bak-ing applications is an endo-1, 4-ß-xylanase. It is not possible to give a general dosage recommendation as there is no stand-ard method of determining hemicellulase activity. The available methods are usu-ally based on determining the release of reducing sugars, the reduction of viscosity or the breakdown of synthetic or coloured molecules and are very difficult to relate to each other. Moreover, even the use of a standard method for different hemicel-lulases does not necessarily permit con-clusions in respect of baking properties, presumably because the points at which hemicellulases of different origin attack the pentosan molecules are too various.

ProteaseProteases (also known as proteinases

or peptidases) split the protein strands of the gluten molecule (Figure 3) and thus lead first to a softening and then to a complete collapse of the structure. A purified single and very specific protease would only be able to break down a few of the peptide bonds, resulting in only limited softening.

With short gluten structures a slight softening may well be desirable; in this case it has a similar significance to the use of L-cysteine. The proteolytic action is more time-dependant than the function of cysteine. As a result, it increases with the fermentation time of the dough. That is why there is a considerable demand for enzyme preparations that do not contain even traces of protease.

The use of protease is less crucial with flours that are rich in gluten. It is even very common in the production of pan (toast) bread, where a soft dough that precisely fills the tin is required. Proteases are also very useful in the production of cracker,

Table 1: Enzymes suggested for bread and flour improvement (not exclusive)

Enzyme Claimed Effect

Alpha-amylase, bacterial Oven-rise, anti-staling, liquefaction

Alpha-amylase, cereal Oven-rise, anti-staling

Alpha-amylase, fungal Energy supply for yeast, dough & bread structure

Alpha-amylase, maltogenic, intermediate heat stable Anti-staling

Ascorbic acid oxidase Protein strengthening

Beta-amylase Energy supply for yeast, browning, taste

Branching enzyme (glucotransferase) Water binding

Cellulase Water binding

Furanosidase, arabinofuranosidase Dough structure, water binding

Ferulic and cumaric acid esterase Dough structure, water binding

Glucoamylase, (amyloglucosidase) Energy supply, colour, flavour

Glutathion oxidase Protein strengthening

ß-glucanase Structure, liquefaction

Glucose oxidase, galactose oxidase, hexose oxidase Protein strengthening

Hemicellulase, xylanase, pentosanase Dough structure, water binding, volume yield

Laccase, polyphenol oxidase Dough strengthening

Carboxyl esterase (lipase, phospholipase, galacto lipase etc.)

Flavour, in-situ emulsification, dough stability and volume yield, dough brightening

Lipoxygenase, lipoxidase Dough structure, decolourization

Exo-Peptidase Colour, flavour

Peroxidase Protein strengthening

Protease, proteinase, endo-peptidase Protein relaxation, liquefaction

Pullulanase Structure, water binding

Sulfhydryl oxidase Protein strengthening

Sulfhydryl transferase Protein strengthening

Transglutaminase Protein cross-linking, gluten stabilization

Figure 3: Action of protease on gluten

Grain&feed millinG technoloGy20 | march - april 2013

FEATURE

biscuit or wafer flours where elasticity of the gluten is not desirable.

Glyco oxidasesThere are several oxidoreductases in

nature that convert sugar molecules into the corresponding acids, or, as in the case of sorbitol oxidase, that convert a sugar alcohol into the corresponding sugar. The most common oxidase (from a commercial perspective) is glucose oxidase. Other exam-ples are maltose or galactose oxidase. More generic terms used for all these enzymes are hexose oxidase or pyranose oxidase.

The enzyme glucose oxidase (GOX) is usually derived from the mould Aspergillus, sometimes from Penicillium species. Honey

is also a rich source of GOX. The enzyme stems from the pharyngeal glands of the bees. However, its suitability is rather restricted by the taste of its carrier.

One effect of GOX in the dough is to oxidize glucose to form gluconic acid with the aid of atmospheric oxygen, but the slight souring that occurs in the process is negligi-ble; its other effect is to transform water into hydrogen peroxide (Figure 4). This oxidizing agent acts on the thiol groups of the gluten, either directly or via several pathways, induc-ing formation of disulphide bonds and thus tightening of the protein. Since hydrogen peroxide is a rather non-specific oxidizing agent, it may also react with other reducible substrates, for instance phenolic component

such as the tyrosine groups in protein or the feruloyl residues in pentosans.

The oxidative cross-linking of the pen-tosans is called oxidative gelation, a reaction resulting in increased dough firmness and dryer dough surfaces. The limiting factor in this process is the availability of oxygen because of other chemical and biochemical reaction consuming oxygen.

Therefore, the conditions for oxidases are only good on the surface of the dough where plenty of oxygen is always available. This limitation can be solved by technical measures during dough preparation, for example overpressure or the supply of extra oxygen through the mixing tool.

Carboxyl esterasesThe term carboxyl esterase comprises

all lipolytic enzymes, for example (triacyl) lipase, phospholipase and galactolipase. They all catalyse the hydrolysis of acyl residues (fatty acids) from lipids. Wheat contains about 2.5-3.3 percent lipids, a typical bread flour about 2.5-2.7 percent (Chung & Ohm, 2009), but only about 1 percent are free lipids that are easily accessible by lipolytic enzymes. A schematic representation of the lipids composition of wheat flour is given in Figure 5. Lipase converts non-polar lipids into the more polar structures diglycerides and monoglycerides, i.e. emulsifiers (Figure 6). Lipids of wheat flour are already polar to some extent, namely phospholipids and gly-colipids are converted into more polar and hydrophilic lyso-forms by phospholipases and glycolipases.

The in situ formation of mono- and dig-lycerides from wheat lipids results in dough strengthening and larger volume yield, but according to the author’s findings doesn’t have a significant effect on starch retrograda-tion and hence bread staling. This is in con-trast to the effect of mono- and diglycerides which are added to a bread formula: due to interaction with starch they are able to reducing the staling rate. On the other hand, their effect on volume yield is very limited. Most probably, the action of enzymatically formed emulsifiers on volume yield is pro-nounced because they are already located at the right sites of the dough for improving the

Figure 4: Reaction of glucose oxidase and some probable effects on dough components

Figure 5: Classification and distribution of the main lipids in wheat flour (averages; % d.s.; modif. from Pomeranz and Chung, 1978, using data from

Chung and Ohm, 2009)

Grain&feed millinG technoloGy march - april 2013 | 21

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biscuit or wafer flours where elasticity of the gluten is not desirable.

Glyco oxidasesThere are several oxidoreductases in

nature that convert sugar molecules into the corresponding acids, or, as in the case of sorbitol oxidase, that convert a sugar alcohol into the corresponding sugar. The most common oxidase (from a commercial perspective) is glucose oxidase. Other exam-ples are maltose or galactose oxidase. More generic terms used for all these enzymes are hexose oxidase or pyranose oxidase.

The enzyme glucose oxidase (GOX) is usually derived from the mould Aspergillus, sometimes from Penicillium species. Honey

is also a rich source of GOX. The enzyme stems from the pharyngeal glands of the bees. However, its suitability is rather restricted by the taste of its carrier.

One effect of GOX in the dough is to oxidize glucose to form gluconic acid with the aid of atmospheric oxygen, but the slight souring that occurs in the process is negligi-ble; its other effect is to transform water into hydrogen peroxide (Figure 4). This oxidizing agent acts on the thiol groups of the gluten, either directly or via several pathways, induc-ing formation of disulphide bonds and thus tightening of the protein. Since hydrogen peroxide is a rather non-specific oxidizing agent, it may also react with other reducible substrates, for instance phenolic component

such as the tyrosine groups in protein or the feruloyl residues in pentosans.

The oxidative cross-linking of the pen-tosans is called oxidative gelation, a reaction resulting in increased dough firmness and dryer dough surfaces. The limiting factor in this process is the availability of oxygen because of other chemical and biochemical reaction consuming oxygen.

Therefore, the conditions for oxidases are only good on the surface of the dough where plenty of oxygen is always available. This limitation can be solved by technical measures during dough preparation, for example overpressure or the supply of extra oxygen through the mixing tool.

Carboxyl esterasesThe term carboxyl esterase comprises

all lipolytic enzymes, for example (triacyl) lipase, phospholipase and galactolipase. They all catalyse the hydrolysis of acyl residues (fatty acids) from lipids. Wheat contains about 2.5-3.3 percent lipids, a typical bread flour about 2.5-2.7 percent (Chung & Ohm, 2009), but only about 1 percent are free lipids that are easily accessible by lipolytic enzymes. A schematic representation of the lipids composition of wheat flour is given in Figure 5. Lipase converts non-polar lipids into the more polar structures diglycerides and monoglycerides, i.e. emulsifiers (Figure 6). Lipids of wheat flour are already polar to some extent, namely phospholipids and gly-colipids are converted into more polar and hydrophilic lyso-forms by phospholipases and glycolipases.

The in situ formation of mono- and dig-lycerides from wheat lipids results in dough strengthening and larger volume yield, but according to the author’s findings doesn’t have a significant effect on starch retrograda-tion and hence bread staling. This is in con-trast to the effect of mono- and diglycerides which are added to a bread formula: due to interaction with starch they are able to reducing the staling rate. On the other hand, their effect on volume yield is very limited. Most probably, the action of enzymatically formed emulsifiers on volume yield is pro-nounced because they are already located at the right sites of the dough for improving the

Figure 4: Reaction of glucose oxidase and some probable effects on dough components

Figure 5: Classification and distribution of the main lipids in wheat flour (averages; % d.s.; modif. from Pomeranz and Chung, 1978, using data from

Chung and Ohm, 2009)

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A SOLID reputation for quality without compromise!

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FEATURE

protein properties; but for anti-staling effects, not enough emulsifier is formed to interfere with starch retrogradation.

Nevertheless, they have a distinct effect on the shelf life of bread because they create a better ‘starting point’ at the beginning of the storage due to improved volume and crumb structure. With the staling rate unchanged, this results also in a better structure (crumb softness) at the end of the storage period.

Interestingly, it is being disputed whether the doughs have to contain additional fat, and if so, what kind of fat, for the lipase to work satisfactorily. According to our findings, fat reduces the efficacy of lipase, probably by ‘distracting’ the lipase from the ‘right target’, i.e. the flour lipids.

Initially, there was also the problem of a possible impairment of taste due to the release of flavour-active fatty acids, particularly if butter is involved. The most recent carboxyl esterase are more specific in this concern and hence do not affect the flavour in most applications.

TransglutaminaseThis enzyme causes bond formation

between protein folds or different pro-tein strands (Figure 7). It needs lysine

and glutamine groups to work. Although lysine is a limited amino acid in flour, the levels are enough for transglutaminase to work. The result is a strengthening effect on the dough, like ascorbic acid.

Because it is rather expensive com-pared to ascorbic acid, its use is limited. A special usage area can be in very long or retarded fermentation processes where very low amounts of the enzyme will work sufficiently long.

Enzymes for biscuits, crackers and wafers

Whereas a high protein content and strong gluten are desired properties in many bread processes, flours with lit-tle and weak gluten are preferable for durable baked goods. The tendency of dough to spring back after rolling and the undesired formation of gluten lumps in wafer batter are the reasons for this requirement. Whether a flour with low and weak protein is available or not, the use of elasticity-reducing agents will have benefits in all stages of the process: The lamination will be more uniform; reduction of the thickness of the dough sheet can be performed faster and more reproducibly; relaxing periods for the dough sheet can be shortened or even

omitted; the dough pieces will keep the shape given by the cutting; shrinkage and bending in the oven as well as the for-mation of hairline cracks (checking) are avoided. With suitable amylases, expen-sive recipe components such as milk solids otherwise necessary for sufficient browning can be omitted. Furthermore, the whole process will be less dependent on flour quality.

Other flour applicationsEnzymes have also been introduced

into flour applications others than bak-ing, for example noodles or steamed bread. For steamed bread the desired properties are similar to those in bread baking, but the technology is quite dif-ferent and requires different types of enzyme compounds. In many types of steamed bread, specific lipases are very useful, providing stability, volume and a bright crumb colour.

Except for certain types of Asian noodles, for example Japanese udon noodles, a firm bite and a high cooking tolerance are advantageous. For instant noodles, the requirements are quite different, because the reduction of oil uptake during frying and a fast water uptake upon cooking are of utmost importance. Furthermore, avoiding the cracking of dried noodles is a typical aim, although this problem is caused in many cases by inadequate drying condi-tions. Finally, the colour of the fresh or dry noodle is important. A bright colour without speckles is a desirable property of many but not all types of noodles. All of these challenges can be approached by enzymes, namely by carboxyl este-rases and lipoxygenases.

References Chung, OK, Ohm, JB, 2009. Wheat Lipids. In:

Wheat - Chemistry & Technology, Khan, K, Shewry, PR (ed.), AACC Press, 363-399.

Pomeranz, Y and Chung, OK, 1978. Interaction of lipids with proteins and carbohydrates in breadmaking. J. Am. Oil Chem. Soc., 285-289 .

Sandstedt RM, Kneen E and Blish MJ, 1939. A standardized Wohlgemuth procedure for alpha-amylase activity. Cereal Chem. 16, 712-723.

More inforMation:Website: www.muehlenchemie.de

Read the second part of this article in the next issue of Grain and Feed Milling Technology. Lutz Popper will discuss additives other than flour and standardisation services.

Figure 6: Effect of carboxylesterases on wheat lipids

Figure 7: Cross linking of protein by transglutaminase

Grain&feed millinG technoloGy22 | march - april 2013

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A subscription magazine for the global flour & feed milling industries - first published in 1891INCORPORATING PORTS, DISTRIBUTION AND FORMULATION

In this issue:

• Measures for increasing the energy efficiency of UFA feed mills in Switzerland

• Importance of trace minerals for nutrient stability in feed

• Managing mill maintenance - Maintenance options and challenges

• Super chilled grains

Mar

ch -

April

201

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• Fine grinding and BS3 Xylanase improve productivity in weaners

• Additives for flour standardisation Part I: Enzymes

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