Colloidal and surface phenomenal aspects of Ice cream.doc

8/11/2019 Colloidal and surface phenomenal aspects of Ice cream.doc

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Colloidal and surface phenomenal aspects of Ice cream

Yusuo Bob Chang

Joseph Kuechle

Travis Reese

Pierre SaintLouis

pril !" #$$#


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Table of Contents

I. Introduction - 3

II. History - 4

III. Design Considerations - 6

IV. Main components and composition - 9

V. Basic structure of Ice cream - 1

VI. Ingredients contri!uting to - 11 p"ysica# properties

VII. $rocessing and Manufacture - %4

VIII. Mar&eting Considerations - 31

I'. (upp#iers - 36

'. Conc#usion - 3)

'I. *eferences - 3+

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I% I&TR'()CTI'&

Homogeni,ed dairy emu#sions suc" as ice cream are genera##y co##oids containing

fat drop#ets as t"e dispersed p"ase. Ice cream is a comp#e food co##oid in t"at t"e mi

emu#sion is su!seuent#y foamed/ creating a dispersed p"ase of air !u!!#es/ and is fro,en/

forming anot"er dispersed p"ase of ice crysta#s. 0ir !u!!#es and ice crysta#s are usua##y

in t"e range of % 2 micrometers in si,e. "e serum p"ase consists of t"e unadsor!ed

casein mice##es in suspension in a free,e-concentrated so#ution of sugars/ unadsor!ed

"ey proteins/ sa#ts and "ig" mo#ecu#ar mass po#ysacc"arides. In addition/ t"e partia##y-

crysta##ine fat p"ase at refrigerated temperatures undergoes partia# coa#escence during t"e

concomitant "ipping and free,ing process/ resu#ting in a netor& of agg#omerated fat/

"ic" partia##y surrounds t"e air !u!!#es and gi5es rise to a so#id-#i&e structure. Various

steps in t"e manufacturing process/ inc#uding pasteuri,ation/ "omogeni,ation/ ageing/

free,ing and "ardening/ contri!ute to t"e de5e#opment of t"is structure. "is paper

discusses t"e "istory/ design considerations/ components/ structure/ co##oida# aspects and

contri!uting e#ements/ processing/ and mar&eting considerations of ice cream.

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II% *IST'RY

Very #itt#e is &non of t"e ear#y "istory of ice cream. It is &non "oe5er/ to

"a5e !een introduced from urope. "e origins of ice cream can !e traced !ac& to t"e 4t"

century B.C. "e *oman emperor 7ero ordered ice to !e !roug"t from t"e mountains and

com!ined it" fruit toppings. During C"ina8s ang period 0.D. 61+-9): ;ing ang of

("ang "ad a met"od of creating ice and mi#& concoctions. It is t"oug"t t"at ice cream as

!roug"t from C"ina !ac& to urope. nited (tates/ it as ser5ed !y some famous

0mericans inc#uding ?eorge @as"ington/ "omas Aefferson/ and Do##ey Madison. In

1)/ ?o5ernor B#aden of Mary#and as recorded as "a5ing ser5ed ice cream to "is

guests. 0 ondon caterer named $"i##ip en,i announced in a 7e or& nespaper t"at

"e ou#d !e offering for sa#e 5arious confections/ inc#uding ice cream in 1))4. "e first

ice cream par#or in 0merica opened in 7e or& City in 1))6.

In t"e ear#y years of ice cream/ sa#t as mied it" ice to #oer and contro# t"e

temperature of t"e mi. "e in5ention of t"e ooden !uc&et free,er it" rotary padd#es

faci#itated its manufacture. It as in 1+3% t"at 0ugustus Aac&son/ a confectioner from

$"i#ade#p"ia/ in5ented an ice cream recipe and a met"od for manufacturing it. In 1+43/

7e ng#and "ouseife 7ancy Ao"nson in5ented t"e "and-cran&ed ice cream c"urn. ("e

patented "er in5ention !ut #ac&ed t"e resources to ma&e and mar&et t"e c"urn "erse#f.

Mrs. Ao"nson so#d t"e patent for % to a $"i#ade#p"ia &itc"en "o#esa#er "o/ !y 1+4)/

made enoug" free,ers to satisfy t"e "ig" demand. =rom 1+4) to 1+))/ more t"an )

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impro5ements to ice cream c"urns ere patented. "e first #arge-sca#e commercia# ice

cream p#ant as esta!#is"ed in Ba#timore in 1+21 !y Aaco! =usse##.

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III% (+SI,& C'&SI(+RTI'&S

aste/ teture/ !ody/ co#oring/ addition of fruits and candies/ me#t resistance/

rigidity/ and ma##ea!i#ity are some of t"e ua#ities t"at a consumer #oo&s for in a good ice

cream. Most of t"ese properties can !e manipu#ated t"roug" t"e use of sta!i#i,ers and

emu#sifiers.

"e f#a5or of t"e ice cream is pro!a!#y its most important ua#ity. =#a5or is

manipu#ated t"roug" t"e use of seeteners/ corn syrup/ natura# and artificia# f#a5ors.

=#a5or defects can !e c#assified according to/ t"e f#a5oring system #ac&s f#a5or or too

"ig" f#a5or/ unnatura# f#a5or:/ t"e seetening system #ac&s seetness or too seet:/

processing re#ated f#a5or defects coo&ed:/ dairy ingredient f#a5or defects acid/ sa#ty/ o#d

ingredient/ oidi,edEmeta##ic/ rancid/ or "ey f#a5ors:/ and ot"ers storageEa!sor!ed:.

0 ua#ity ice cream needs to possess a smoot" and creamy teture/ "ic" is

inf#uenced !y si,e/ distri!ution/ s"ape and num!er of ice crysta#s. Ice crysta#s gi5e t"e

product a course/ icy teture. Ice crysta#s are usua##y formed "en t"e product goes

t"roug" F"eat s"oc&G or t"e temperature f#uctuations eperienced from storage and

distri!ution. "e amount and si,e of ice crysta#s is inf#uenced !y t"e use of sta!i#i,ers/

addition of t"e rig"t amount of so#ids/ free,ing and "ardening time/ and t"e incorporation

of air and temperature f#uctuations. =#uffy and sandy tetures are a#so c"aracteristics t"at

s"ou#d !e a5oided. 0 f#uffy teture is c"aracteri,ed as spongy and is caused !y t"e

incorporation of #arge amount of air as #arge air ce##s/ #o tota# so#ids and #o sta!i#i,er

content. 0 sandy teture is one of t"e most o!ectiona!#e teture defects !ut easiest to

detect. It is caused !y #actose crysta#s/ "ic" do not disso#5e readi#y and produce a roug"

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>ne5en co#oring usua##y app#ies to ice cream in "ic" co#or "as added/ !ut may !e

noticed in 5ani##a ice cream under some circumstances. >nnatura# co#ors arise "en a

rong s"ade of co#or used for a f#a5ored ice cream/ too muc" ye##o co#oring used in

5ani##a ice cream/ or "en neutra#i,ation causes a grayis" co#or.

("rin&age is a 5ery trou!#esome defect in ice cream since t"ere appears to !e no

sing#e cause or remedy. Defects s"o up in "ardened ice cream and manifest t"emse#5es

in reduced 5o#ume of ice cream in t"e container usua##y !y pu##ing aay from t"e top

andEor sides of container. (tructura##y/ it is caused !y a #oss of sp"erica# air !u!!#es and

formation of continuous air c"anne#s. (ome factors !e#ie5ed associated it" t"e defect

areJ free,ing and "ardening at u#tra #o temperatures/ storage temperature/ ecessi5e

o5erruns/ pressure c"anges.

In recent years/ t"ere "as !een a "ig"er demand for t"e inc#usion of candies and

fruit in ice cream. Ice cream inc#usions can come in to different formsJ pieces or

5ariegates. $ieces range from sma## f#ec&s of 5ani##a !ean to partia# or "o#e !ite-si,e

pieces of materia# #i&e fruits and nuts. Variegates often are used instead of/ or in addition

to/ pieces. In t"e finis"ed ice cream/ 5ariegates appear as a ri!!on. "ese inc#usions

ma&e for more difficu#t processing. 7ot ust any candy !ar can ust !e added to ice

creamK t"e ingredient impacts t"e properties of t"e ice cream itse#f and often times t"e

free,ing process c"anges t"e ingredient.

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I-% .ain components and composition

Ice cream contains fi5e main typica# ingredientsJ mi#&/ sta!i#i,ers/ emu#sifiers/

seeteners and ater. (eeteners are o!5ious#y used to en"ance t"e seetness of t"e

fro,en treat. Mi#& consists of mi#& fats and mi#& so#ids. In 7ort" 0merica/ fats are

genera##y deri5ed from mi#& "ereas in ot"er parts of t"e or#d/ fats are more common#y

deri5ed from non-dairy sources. "e mi#& so#id non-fats contain #actose/ casein/ mice##es/

"ey proteins/ minera#s as":/ 5itamins/ acids/ en,ymes/ and gases of t"e mi#& or mi#&

products from "ic" t"ey ere deri5ed.

(ta!i#i,ers are present in ice cream to produce smoot"ness in !ody and teture/

retard or reduce ice and #actose crysta# grot" during storage and pro5ide uniformity to

t"e product and resistance to me#ting. mu#sifiers are sometimes integrated it"

sta!i#i,ers/ !ut t"ey function to impro5e t"e "ipping ua#ity of t"e mi/ produce a drier

ice cream to faci#itate mo#ding for 5arious ice cream sty#es/ pro5ide smoot"er !ody and

teture in t"e fina# product and gi5e t"e product good standup properties and me#t

resistance.

"e percent compositions of t"e ingredients are summari,ed in t"e ta!#e !e#o.

ComponentRange(%)

Milkfat 10-16%

Milk Solids-not-fat 9-12%Sucrose 9-12%

Corn Srup Solids !-6%

Sta"ili#ers$mulsifiers 0-0&'%

otal Solids 6-!'%

*ater ''-6!

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-% BSIC STR)CT)R+

"e comp#e p"ysica# structure of ice cream presents a c"a##enge for food

c"emists/ "o readi#y concede itLs not fu##y understood. Despite t"is/ food products

designers &no "o to manipu#ate t"ese structures/ creating a ide 5ariety of products

pac&ing consumer appea#.

@ater/ ice/ air/ sugar/ mi#& fat and mi#& protein can !e assem!#ed into innumera!#e

com!inations/ eac" it" uniue p"ysica# c"emistry. Ice creamLs sensory attri!utes/

particu#ar#y mout"-fee#/ dictate t"at ingredient and processing 5aria!#es in its production

stri5e for as muc" "omogeneity as possi!#e/ e5en t"oug" ice cream is far from

"omogeneous.

(imp#y stated/ ice creamLs o5era## design goa# isJ incorporating se5era# different

inso#u!#e air !u!!#es/ ice crysta#s/ and fat g#o!u#es: into an aueous p"ase at t"e sma##est

si,es/ and in t"e greatest num!ers/ possi!#e.


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-I% Ingredients contributing to ph/sical properties as colloids on a molecular

o create an ice cream product it" properties meeting

customer epectations/ eac" e#ement of it must contri!ute

to its properties. 7ot on#y t"e properties of t"e ingredients

a#one contri!ute to suc" a product !ut t"e ingredients as

t"ey interact in a co##oida# system a#so p#ay a great ro#e in

s"aping t"ese attri!utes.

=at and @ater

"e most a!undant components in ice cream are t"e

most important. "ese are ater and fat. "e interaction

!eteen t"e fat and ater t"emse#5es is not "at is uniue a!out ice cream !ut it is t"e

manipu#ation of t"is interaction t"at pro5ides t"e ua#ities of ice cream.

=at/ a#so &non as a triacy#g#ycero#/ is #arge in mo#ecu#ar eig"t. "e fat mo#ecu#e is

made up of t"ree fatty acids !ound to a g#ycero# mo#ecu#e. "is mo#ecu#e is most#y non-

po#ar and 5ery #arge in eig"t. It ad"eres to itse#f t"roug" Vanderaa#s interactions

imp#ying re#ati5e#y #arge co"esi5e properties. Due to t"e re#ati5e#y saturated nature of t"e

mo#ecu#es it" sing#e !onds in mi#&/ as e## as t"e #o temperatures t"ey are &ept at/

t"ey tend to !e more so#id #i&e t"an in ot"er types of foods t"at use unsaturated fatty

acids. "is is necessary to maintain t"e rigidity of t"e ice cream. "e trig#ycerides in mi#&

fat "a5e a ide me#ting range around O4 C/ and t"us t"ere is a#ays a com!ination of

#iuid and crysta##ine fat. "e fat used from mi#& is a#so important to ice cream due to t"e

fact t"at it increases t"e ric"ness of f#a5or in ice cream. It produces a c"aracteristic

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smoot" teture !y #u!ricating t"e pa#ate. "e disad5antages in use of mi#& fat as a

component inc#ude "ig" cost/ "indered "ipping a!i#ity/ ecessi5e ric"ness in f#a5or/ and

"ig" ca#orie 5a#ue. "e !est source of mi#& fat in ice cream for "ig" ua#ity f#a5or is fres"

seet cream from fres" seet mi#&. Dup#icating t"e fat used in ice cream from ot"er

sources of fat is difficu#t.

@ater is a #o mo#ecu#ar eig"t po#ar su!stance it" "ig" co"esi5e properties due to

its a!i#ity to "ydrogen !ond. @"at !ecomes created "en a miture of t"e proportions of

fat and ater used "ere is an emu#sion. Here t"ere is a dispersed p"ase of fat in a ater

en5ironment. "e proportions are genera##y suc" t"at $"i P .3. $"i is &non as t"e o

interna#-p"ase ratio I$*: "ere $"i Q Vi E Vi O Ve: "ere Vi Q 5o#ume of interna#

p"ase and Ve Q 5o#ume of eterna# p"ase.

"ese fats "a5e a muc" #oer affinity toards t"e ater t"an it does for itse#f. "is

#eads to "ydrop"o!ic interactions/ "ic" promotes agg#omeration of t"e fats. "ey a#so

are #ess dense t"an ater and tend to f#oat. "ese fats "a5e a #o so#u!i#ity in ater

yie#ding to a p"ase separation of 14R E. "e dispersed p"ase drop#et si,e ranges from

.1 - 1 m.

In ice cream t"e fat is mec"anica##y dispersed. Hoe5er/ t"e emu#sions are unsta!#e

!ecause t"e "ydrop"o!ic interactions descri!ed a!o5e/ and "as a tendency to dri5e t"e

system to f#occu#ate. It is t"is a!i#ity t"at t"e fat "as to recom!ine t"at #eads to a netor&

of fat g#o!u#es. It is promoted !y t"e fact t"at t"e fat g#o!u#es "a5e a decreased diffusion

c"aracteristic as co##oids as opposed to indi5idua# mo#ecu#es in t"e fro,en ater. 0#so/

t"ey "a5e a #arge surface to 5o#ume ratio/ "ic" natura##y #eads to t"is type of netor&

formation as opposed to #arge g#o!u#es. 0t t"e temperature !e#o free,ing t"e fat

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interactions i## dra t"e mo#ecu#es toget"er. "e fat tissue in ice cream is not ionic !ut

t"ere are ions in t"e matri and disso#5ed in t"e fats. Ionic surfactants are added to t"e

surface of drop#ets and esta!#is" an e#ectric dou!#e #ayer in t"e aueous p"ase sta!i#i,ing

t"e emu#sion. "ese emu#sifying agents increase t"e amount of fat g#o!u#es effecting fat

netor& and sta!i#i,e t"e emu#sion.

0n additiona# effect of t"ese emu#sifying agents is t"e fact t"at t"eir addition #eads to

an inf#u of protein mo#ecu#es into t"e serum p"ase during co#d aging. "e proteins tend

to adsor! to t"e fat serum interface and increases t"e concentration in t"e serum from t"e

fat. "is c"ange desta!i#i,es t"e fat g#o!u#es !y decreasing t"e protein steric sta!i#i,ation.

"is i## !e addressed in t"e section considering t"e proteins.

Before t"e free,ing step emu#sifiers decrease t"e a!i#ity of t"e fat to coa#esce/ "ic"

ou#d "appen natura##y due to t"e energy in5o#5ed. During t"e free,ing step t"ey add to

t"e partia# desta!i#i,ation of t"e #ipid p"ase. During "ipping/ t"e emu#sifier causes t"e

fat g#o!u#es to agg#omerate and form a netor& in t"e continuous ater p"ase !eteen

air !u!!#es. 0s a resu#t/ air ce##s are sta!i#i,ed and stiffness of t"e foam can !e en"anced.

=oam is t"e second co##oida# p"ase of ice cream it" air and #iuids !eing mied. "e

interfacia# energy !eteen t"e fat and air it" emu#sifiers added is #oer t"an t"e aterE

fat interface forcing t"e fat more into t"e air. "is assists in t"e de5e#opment of a good

aeration and fat distri!ution to maintain t"e correct smoot"ness and #ig"tness of teture in

t"e ice cream. @"en emu#sifier concentration is increased t"ere is a greater penetration of

fat into t"e air p"ase.

"e tota# contri!ution of emu#sifiers is decreased free,ing time/ impro5ed "ipping

ua#ity and a production of a dry/ fine/ stiff teture of ice cream t"at me#ts uniform#y.

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"e origina# ice cream emu#sifier as egg yo#& !ut t"e modern concoction uses to

!asic materia#s. "ese are sor!itan esters suc" as

po#y sor!ate + as e## as mono and di g#ycerides.

"e main ingredient in egg yo#& t"at as and

is sti## used as an amp"ip"i#ic emu#sifier is

#ec"t"in. ec"t"ins are a miture of

p"osp"o#ipids inc#uding p"osp"atidy# c"o#ine/

p"osp"atidy# et"ano#amines or inosito# p"osp"atides and many ot"ers. "ey are a#so

deri5ed from soy!eans and can !e c"emica##y modified to pro5ide a ide range of

"ydrop"o!icEp"i#ic !a#ances for 5arious app#ications to pro5ide a range of interfacia#

tensions and effecti5e areas.

$o#ysor!ates are deri5ed from a sor!itan ester consisting

of a g#ucose a#co"o# sor!ito#: mo#ecu#e !ound to a fatty acid/

o#eic acid/ it" oyet"y#ene groups added for furt"er ater

so#u!i#ity. $o#y sor!ate + is sma## in mo#ecu#ar eig"t and

produces a #o interfacia# tension disp#acing more protein

resu#ting in a 5ery t"in mem!rane around t"e fat and a

maimum amount of fat desta!i#i,ation

$o#y sor!ate is a#so a drying agent t"at adsor!s ater increasing t"e concentration of

sugars and proteins in t"e serum p"ase.

Mono and dig#ycerides are deri5ed from t"e partia# "ydro#ysis of fats or oi#s of anima#

or 5egeta!#e origin. Disti##ed monog#ycerides/

especia##y ones !ased on fu##y "ydrogenated fats/

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act a#so as starc" comp#eing agents due to t"eir straig"t car!on c"ain. "is c"ain is

en5e#oped !y t"e "e#ica# configuration of amy#ose to form a comp#e t"at is inso#u!#e in

ater. 0#tering t"e c"emica# properties of ot"er mo#ecu#es in ice cream.

(ta!i#i,ers

"e #iuid ater or serum p"ase a#so "as structures in it t"at are affected !y

co##oids and surface p"enomena as e## as p"ysica# nature of diffusion.


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sac"arides. "is means t"at t"ey are po#ymers of simp#e sugars t"at are made of rings and

usua##y are in t"e formu#a C6H1%


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of tota# so#ids.


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Mi#& protein can !e categori,ed as caseins/ "ey proteins/ and proteins associated

it" t"e #ipid p"ase.

Caseins are a fami#y of re#ated p"osp"oproteins precipitated from ra s&im mi#&

at a pH of 4.6 and at a temperature of % oC as casein mice##es it" associated ca#cium.

"e casein fraction comprises a!out +R of t"e tota# protein content of mi#&. 0 so#u!#e

caseinate can !e o!tained !y raising pH to 6.). Caseins eist in #arge sp"erica# co##odia#

mice##es it" ca#cium p"osp"ate. "ese mice##es comprise 93R E: caseins and range

in si,e from 2 to 3 0 in diameter. "e ca#cium and p"osp"ate p#ay a 5ery important

ro#e in maintaining t"e integrity of t"e casein mice##es/ and are common#y referred to as

co##oid ca#cium p"osp"ate. Caseins are p"osp"oproteins

@"ey protein is o!tained from s&im mi#& after separation of casein in c"eese

production. @"ey protein is so#u!#e at #o pH #e5e#s/ at "ic" proteins from ot"er

sources coagu#ate and sett#e out. Casein is preferentia##y a!sor!ed o5er "ey at t"e

interface.

"ere is a certain #e5e# of protein dep#etion from t"e fat p"ase t"at must !e

eceeded !efore partia# coa#escence occurs. "is resu#ts in increased "ydrop"o!icity at

fat surface/ decrease of me#ting rate/ increased s"ape retention due to fat netor& and a

degree of emu#sion desta!i#i,ation. $roteins a#so impro5e t"e teture of t"e ice cream

(eeteners

"e consumer usua##y desires a seet ice cream. 0s a resu#t/ seetening agents

are added to ice cream mi at a rate of usua##y 1%-16R !y eig"t. (eeteners impro5e

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t"e teture and pa#ata!i#ity of t"e ice cream/ en"ance f#a5ors/ and are usua##y t"e c"eapest

source of tota# so#ids.

In addition/ t"e sugars/ inc#uding t"e #actose from t"e mi#& components/

contri!ute to a depressed free,ing point so t"at t"e ice cream "as some unfro,en ater

associated it" it at 5ery #o temperatures typica# of t"eir ser5ing temperatures/ -12 to

-1+ C. @it"out t"is unfro,en ater/ t"e ice cream ou#d !e too "ard to scoop. "is is a

simi#ar action as t"e sta!i#i,erL "ydration !ut it is t"ese mo#ecu#es concentration t"at

direct#y effects t"e free,ing point. 0n ecess of #actose can #ead to t"e defect of sandiness

pre5a#ent "en t"e #actose crysta##i,es out of so#ution. cessi5e concentrations of

#actose in t"e serum p"ase may a#so #oer t"e free,ing point of t"e finis"ed product to an

unaccepta!#e #e5e#.

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"is process of free,e concentration continues to 5ery #o temperatures. 5en at t"e

typica# ice cream ser5ing temperature of -16S C/ on#y a!out )%R of t"e ater is fro,en.

"e rest remains as a 5ery concentrated sugar so#ution. "us "en temperature is p#otted

against R ater fro,en/ one gets t"e p"ase diagram s"on !e#o. "is "e#ps to gi5e ice

cream its a!i#ity to !e scooped and c"eed at free,er temperatures.

"e effect of seeteners on free,ing c"aracteristics of ice cream mies is

demonstrated !y t"e p#ot on t"e ice cream free,ing cur5e.

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increase or decrease t"at c"arge as t"ey ere attracted to or repe##ed from surface.

Desta!i#i,ation is a#so effected !y p"/ "ic" affects many of t"e mo#ecu#es and t"eir

a!i#ity to !e "ydrop"i#ic or "ydrop"o!ic.

0dditi5es

=ruits/ nuts/ candy add crysta# centers and may en"ance #actose crysta##i,ation.

7uts pu## out moisture from ice cream immediate#y surrounding t"e nut t"us

concentrating t"e mi.

o maintain t"e !a#ance !eteen t"ese many different p"ases is 5ery difficu#t.

Different concentrations of emu#sifiers/ sta!i#i,ers/ proteins and fats and t"e different

types of eac" mo#ecu#es used effect t"e properties e#icited.

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-II% PR'C+SSI&, &( .&)0CT)R+

Ma&ing ice cream is an art and a science "et"er in a processing p#ant or "ome.

In !ot" cases/ t"e ingredients are !asic. =irst/ you need coLs mi#& and cream. 7et come

sugar from cane and eggs from c"ic&ens. "en/ f#a5oring is added-5ani##a/ !eans/

peppermint/ or c"oco#ate/ for eamp#e.

(afety Concerns

"e ice cream you !uy at t"e store or at an ice cream par#or is carefu##y measured

and mied/ and most certain#y c"ec&ed for safety at e5ery step. (cientists ma&e sure of

t"at/ safety inspectors ma&e sure t"at a## t"e miing/ coo#ing/ storage/ and pac&aging

protects your "ea#t"/ too. Mi#& is pasteuri,ed and t"e eggs are coo&ed to ma&e sure t"e

fina# product is not on#y tasty/ not safe.

Basic steps in t"e manufacturing of ice cream

"e !asic steps in t"e manufacturing of ice cream are genera##y as fo##osJ

-B#end t"e mi ingredients

-$asteuri,e

-Homogeni,e

-0ge t"e mi

-=#a5or

-=ree,e

-$ac&age

-Hard =ree,e

-(tore

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0lo1 diagram for ice cream processing

B#ending

=irst t"e ingredients are se#ected !ased on t"e desired formu#ation and t"e

ca#cu#ation of t"e recipe from t"e formu#ation and t"e ingredients c"osen/ t"en t"e

ingredients are eig"ed and !#ended toget"er to produce "at is &non as t"e ice cream

mi. B#ending reuires rapid agitation to incorporate poders/ and often "ig" speed

!#enders are used.

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$asteuri,ation

"e mi is t"en pasteuri,ed. $asteuri,ation is t"e !io#ogica# contro# point in t"e

system/ designed for t"e destruction of pat"ogenic !acteria. In addition to t"is 5ery

important function/ pasteuri,ation a#so reduces t"e num!er of spoi#age organisms suc" as

psyc"rotrop"s/ and "e#ps to "ydrate some of t"e components proteins/ sta!i#i,ers2%

Bot" !atc" pasteuri,ers and continuous H(: met"ods are used.

Batc" pasteuri,ers #ead to more "ey protein denaturation/ "ic" some peop#e

fee# gi5es a !etter !ody to t"e ice cream. In a !atc" pasteuri,ation system/ !#ending of t"e

proper ingredient amounts is done in #arge ac&eted 5ats euipped it" some means of

"eating/ usua##y steam or "ot ater. "e product is t"en "eated in t"e 5at to at #east 69 C

122 =: and "e#d for 3 minutes to satisfy #ega# reuirements for pasteuri,ation/ necessary

for t"e destruction of pat"ogenic !acteria. Various time temperature com!inations can !e

used. "e "eat treatment must !e se5ere enoug" to ensure destruction of pat"ogens and to

reduce t"e !acteria# count to a maimum of 1/ per gram. =o##oing pasteuri,ation/

t"e mi is "omogeni,ed !y means of "ig" pressures and t"en is passed across some type

of "eat ec"anger p#ate or dou!#e or trip#e tu!e: for t"e purpose of coo#ing t"e mi to

refrigerated temperatures 4 C:. Batc" tan&s are usua##y operated in tandem so t"at one is

"o#ding "i#e t"e ot"er is !eing prepared. 0utomatic timers and 5a#5es ensure t"e proper

"o#ding time "as !een met.

Continuous pasteuri,ation is usua##y performed in a "ig" temperature s"ort time

H(: "eat ec"anger fo##oing !#ending of ingredients in a #arge/ insu#ated feed tan&.

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Homogeni,ation of t"e mi s"ou#d ta&e p#ace at t"e pasteuri,ing temperature. "e "ig"

temperature produces more efficient !rea&ing up of t"e fat g#o!u#es at any gi5en pressure

and a#so reduces fat c#umping and t"e tendency to t"ic&/ "ea5y !odied mies. 7o one

pressure can !e recommended t"at i## gi5e satisfactory resu#ts under a## conditions. "e

"ig"er t"e fat and tota# so#ids in t"e mi/ t"e #oer t"e pressure s"ou#d !e. If a to stage

"omogeni,er is used/ a pressure of % - %2 psi on t"e first stage and 2 - 1 psi

on t"e second stage s"ou#d !e satisfactory under most conditions. Homogeni,ation

!egins t"e process of fat structure formation. 0fter pre"eating or pasteuri,ation/ t"e mi

is at a temperature sufficient to "a5e me#ted a## t"e fat present/ and t"e fat passes t"roug"

one or to "omogeni,ing 5a#5es/ creating g#o!u#es of .2 to %. Tm. Immediate#y

fo##oing "omogeni,ation/ t"e ne#y formed fat g#o!u#e is practica##y de5oid of any

mem!ranous materia# due to its tremendous increase in surface area and readi#y adsor!s

amp"ip"i#ic mo#ecu#es from so#ution. "e transit time t"roug" a "omogeni,ation 5a#5e is

in t"e order of 1-2 to 1-6 s. $rotein adsorption occurs uicy/ !ut unfo#ding and

rearrangement at t"e interface may ta&e minutes or e5en "ours to !e comp#ete

0ging

"e mi is t"en agedfor at #east four "ours and usua##y o5ernig"t. "is a##os time

for t"e fat to coo# don and crysta##i,e/ and for t"e proteins and po#ysacc"arides to fu##y

"ydrate. 0ging pro5ides t"e fo##oing functionsJ

Impro5es "ipping ua#ities of mi and !ody and teture of ice cream

It does so !yJ

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pro5iding time for fat crysta##i,ation/ so t"e fat can partia##y coa#esceK

a##oing time for fu## protein and sta!i#i,er "ydration and a resu#ting s#ig"t

5iscosity increaseK

a##oing time for mem!rane rearrangement and proteinEemu#sifier interaction/ as

emu#sifiers disp#ace proteins from t"e fat g#o!u#e surface/ "ic" a##os for a

reduction in sta!i#i,ation of t"e fat g#o!u#es and en"anced partia# coa#escence.

0ging is performed in insu#ated or refrigerated storage tan&s/ si#os/ etc. Mi temperature

s"ou#d !e maintained as #o as possi!#e it"out free,ing/ at or !e#o 2 C. 0n aging time

of o5ernig"t is #i&e#y to gi5e !est resu#ts under a5erage p#ant conditions. 0 green or

unaged mi is usua##y uicy detected at t"e free,er.

@"ipping

"e net stage of structure de5e#opment occurs during t"e concomitant "ipping

and free,ing step. 0ir is incorporated eit"er t"roug" a #engt"y "ipping process !atc"

free,ers: or dran into t"e mi !y 5acuum or inected under pressure. 0ir !eing

incorporated into t"e mi at t"is time especia##y if pre-"ipping de5ices are !eing used:

is t"oug"t to !e first surrounded !y a proteinaceous mem!rane. In addition to air

incorporation/ t"e "ipping process app#ies a considera!#e s"ear stress to t"e mi/ and

t"at s"ear rate increases as ice crysta#s form during free,ing/ #i&e#y due to a com!ination

of t"e addition of partic#es and to free,e-concentration of t"e fat and aueous p"ase. "e

continued "ipping process and app#ied s"ear stress cause t"e emu#sion to undergo

partia# coa#escence or fat desta!i#i,ation/ during "ic" c#umps and c#usters of t"e fat

g#o!u#es form and !ui#d an interna# fat structure or netor& into t"e fro,en product !y

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entrapping air it"in t"e coa#esced fat. "is coa#escing fat interacts it" t"e proteins at

t"e air !u!!#e mem!rane in a 5ery ana#ogous manner to t"e "ipping of "ea5y cream.

$artia# coa#escence occurs in t"e a!sence of air/ !ut t"e presence of air during s"ear stress

i## increase partia# coa#escence considera!#y. i&eise/ t"e app#ied s"ear stress a#so

increases partia# coa#escence considera!#y compared to t"e sparging of air.

=ree,ing and Hardening

=o##oing mi processing/ t"e mi is dran into a f#a5or tan& "ere any #iuid

f#a5ors/ fruit purees/ or co#ors are added. "e mi t"en enters t"e dynamic free,ing

process t"at !ot" free,es a portion of t"e ater and "ips air into t"e fro,en mi. "e

!arre# free,er is a scraped-surface/ tu!u#ar "eat ec"anger/ "ic" is ac&eted it" a

!oi#ing refrigerant suc" as ammonia or freon. Mi is pumped t"roug" t"is free,er and is

dran off t"e ot"er end in a matter of 3 seconds/ or 1 to 12 minutes in t"e case of

!atc" free,ers: it" a!out 2R of its ater fro,en. "ere are rotating !#ades inside t"e

!arre# t"at &eep t"e ice scraped off t"e surface of t"e free,er and a#so das"ers inside t"e

mac"ine "ic" "e#p to "ip t"e mi and incorporate air.

3


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-II% .ar3eting Considerations

Demand

0ccording to a 7ie#sen sur5ey of supermar&et sa#es/ ice cream is 0mericaLs

fa5orite dessert. "e demand for ice cream a#ays eists/ and it tends to gro/ not to

decrease. 0nd many producers of ice cream are rig"t "en say t"at t"is !usiness is

paying/ !ecause eac" 0merican consumes a year#y a5erage of %3.)2 uarts of ice cream/

ice mi#&/ s"er!et/ ice and ot"er commercia##y produced fro,en dairy products/ "ic"

trans#ates to 1.6 !i##ions ga##ons.

Hoe5er t"e 7ort"ern Centra# states "a5e t"e "ig"est per capita consumption of ice

cream at 41.) uarts. "e top t"ree cities in 0merica t"at purc"ase t"e most ice cream on

a per capita !asis areJ $ort#and/


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5. Cocolate - 8 percent

!. Ca"e and coo"ie favors - #.5 percent

#. Neapolitan - # percent

8. $ter - 5.5 percent

%. Co&ee'moca - 3 percent

Demand for Fnatura#G ice cream

Based on natura# "ydroco##oids/ t"e product portfo#io of =MC Biopo#ymer is e##

adapted to t"e companiesL customers and t"e consumer focus on products t"at are natura#/

!iodegrada!#e/ and sourced from 5egeta!#e origins.

"e dri5ing forces !e"ind t"is continuous trend are t"e genera# impro5ement in

consumersL "ea#t" aareness and ne tec"no#ogy. *ecent#y/ t"is trend "as !een fue#ed !y

more stringent food and safety regu#ations !eing enacted in many countries. "e trend is

a g#o!a# p"enomenon/ !ut t"ese forces "a5e traditiona##y !een most pronounced in

7ort"ern urope and 7ort" 0merica/ "ere consumers "a5e !een concerned a!out

rep#acing so-ca##ed Fun"ea#t"yG ingredients it" F"ea#t"yG ones for uite some time.

0#ginate "as earned a reputation as a F"ea#t"yG ingredient. 0#ginate and

carrageenan are comp#ete#y natura#/ renea!#e and !iodegrada!#e. @"en used in foods or

p"armaceutica# products/ a#ginate and carrageenan are eit"er meta!o#i,ed or a!sorded in

t"e course of t"e !io#ogica# cyc#e. In #ine it" t"e opinions of estern researc"ers and

eig"t reduction eperts "o recommend cutting don on dietary fats and sugar/ in

recent years t"ere "as !een ep#osi5e grot" in #o-ca#orie and #o-fat products.

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In ot"er ords/ t"ere is groing demand for products containing #o #e5e#s of fat or

fat su!stitutes or no fat at a##. et it is not easy to rep#ace fat. Its appearance/ teture and

taste go5ern our perception of t"e food e eat/ and fat often p#ays an important ro#e in

t"ese factors. In fatty/ ater products/ it is essentia# t"at t"e teture remains sta!#e and

#ea5es a good Ufee#ingL in t"e mout".


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in t"e >nited (ates. oday a#most e5ery nationa# !rand is under &os"er super5ision

inc#uding Haagen-Da,s/ Ben AerryLs/ ?odi5a/ (tar!uc&s and dyLs Dreamery.

Cost for production purc"ase

i&e a## food products/ a premise is reuired t"at conforms to t"e "ygiene

#egis#ation in t"e > Directi5e 9%E46EC.

=or ice cream production/ one needs a processing area/ a co#d room and a free,er

room/ an area to store dry ingredients and an area to store pac&aging. uipment for

processing is 5ery specific and uite epensi5e. 0 miing 5at/ "omogeni,er/ free,er/ and

fruit !#ender ou#d cost approimate#y 2/. "is ou#d "a5e a production capacity

of +-1 #iters of ice cream per "our.

Cost of 1 #iter of dairy ice cream mi 3+R .(. 1%R =at: Q 1.1


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Ben AerryLs ).2E

Carte DL


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4% Conclusion

(omet"ing seeming so simp#e and yet sti## so comp#e can sti## !e enoyed as it

"as !een for centuries in pure seet !#iss !ut t"e enoyment on#y gros "en one can

understand t"e p"ysica# principa#s !e"ind ice cream.

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4I% References

Books

Dic&inson/ ./ and @a#stra/ $. =ood co##oids and po#ymersJ sta!i#ity and mec"anica#

properties 7e or&/ Springer Verlag/ 1993

Dic&inson/ ./ orient D. =ood macromo#ecu#es and co##oids 7e or&/ Springer Verlag/1992

=ennema/

Colloidal and surface phenomenal aspects of Ice cream.doc

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