ice cream guide

UNIT 10 PACKAGING, HARDENING,STORAGE, TRANSPORTATIONAND COMMON DEFECTS

Structure

10.0 Objectives

10.1 Introduction

10.2 Packaging of Ice Cream and Frozed Desserts

10.3 Hardening and Storage

10.4 Transportation of Frozen Desserts

10.5 SensoryAttributes

10.6 Common Defects and their Remedy

10.7 Let Us Sum Up

10.8 Key Words

10.9 Some Useful Books

10.10 Answers to Check Your Progress

10.0 OBJECTIVES

After reading this unit, we shall be able to:

Types of packaging materials used in packaging of ice-cream

Importance of hardening of ice-cream and the method

Methods of transportation of ice-cream and frozen desserts

Desired sensory attributes of good quality ice-cream

Defects occurring in ice cream, their causes and remedies.

10.1 INTRODUCTION

In the earlier unit we studied how the ice cream mix, properly pasteurized,homogenized and aged, is frozen in an ice cream freezer. Freezing process in the icecream freezer involves conversion of part of water of ice cream mix into smaller icecrystals with simultaneous incorporation of air in the mix to increase the volume(over run) of ice cream. The partially frozen ice cream is then quickly drawn fromthe freezer, filled in suitable containers and transferred to a very low temperatureroom for freezing of remaining water portion of ice cream.After ice cream has beensufficiently hardened it is ready for consumption. Until it is sold to customer, icecream should be properly handled such that the quality of ice cream is not affectedin anyway.This can be achieved bymaintaining cold temperature conditions duringhandling, storage and transportation of ice cream. Good quality ice cream can onlybemadebyselection ofgoodqualityingredients andmaintainingstandard processingconditions avarious stages of manufacture.Qualityof ice creamshould be evaluatedroutinelybyorganoleptic tests bycomparing with approved or accepted score card

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for this purpose. If any defects are noticed in ice cream the reasons for theiroccurrence shouldbe identified and suitablemeasures be taken toremove thedefects.

10.2 PACKAGING OF ICE CREAM AND FROZEDDESSERTS

Generally packaging of ice cream is done before hardening. In few cases it is doneafter hardening. When ice cream is drawn from the freezer, it is usuallycollected incontainers, which give it the desired shape or size for convenient handling duringhardening, storage and marketing

The important requirements of packages for ice cream are:

Protection against contamination

Attractiveness

Ease of opening and re-closure

Ease of disposal

Desirable requirements of packages are:

Protection against moisture

Protection against temperature fluctuations

Ice cream packages are of two types:

i) Multi- service: These types of packages are in limited use only. Tinned steelcans or stainless steel cans of different sizes and shapes are used. These cansare cleaned, sanitized and used repeatedly.

ii) Single-service: These types of packages are now more popular and areavailable for bothbulk sale and retail sale.As the namesuggests these packagesare used and discarded after use. Ice cream for bulk sale is packaged incontainers with capacities ranging from 5 to 25 liters or more. Ice cream in thistype of containers is distributed for sale of dipped ice cream especially in icecream parlors, hotels etc. Ice cream is packaged in fibre-board cartons coatedwith wax or provided with plastic liners.All plastic cylindrical containers withre-closable lids are also now available for bulk packaging especially for carryhome packages.

For retail sale, ice cream is filled in small cups or cartons. The cups may be madeout of paper or card-board treated with wax or plastic. Plastic cups of various sizesand shapes with lids are also available for packaging of ice cream.

In many of the ice cream factories the present trend is to make bricks of varyingsizes. The bricks are made from the moulds into which ice cream has been filledafter leaving the freezer and then hardened. The solid block of ice cream is first cutin smaller size and then wrapped in parchment paper or plastic film. This method ofpackaging is rapidly increasing in popularity. In view of large number of paperwrapped ice cream bricks sold in market, the hygienic quality of wrapping paperassumes considerable importance. It is essential to use only the best qualityof paperfor the purpose.

Other ice cream and frozen desserts, which are first hardened and thenpackagedinclude chocolate coated ice cream in sticks, ice cream sandwiches,popcicles, water ices in sticks etc. These are first filled in moulds after freezing and

Packaging, Hardening,Storage, Transportation

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then hardened. The hardened materials are removed from moulds and wrapped insuitable packagingmaterials.

10. 3 HARDENINGAND STORAGE

Hardening is a continuation of freezing process. Onlypart of water in ice cream mixis converted into small ice crystals in the ice cream freezer. When ice cream isremovedfromfreezerandput in thepackagingmaterials ithasasemi fluidconsistencynot stiff enough to hold its shape. Therefore freezing process is continued withoutagitation in a very low temperature room until the temperature of ice cream reaches–18 °C or below, preferably –30°C. This process is called hardening of ice cream.The refrigerated place where the hardening takes place is called hardening room orhardening chamber or cabinet.

Quick freezingof ice cream duringhardening is also desirable. Slow hardening willfavour large ice crystals formation in ice cream and hence the texture of ice creamwillbecoarse.Timerequired tocompletehardeningprocessdependson thefollowingfactors:

Initial compositionofmix

Temperature of ice cream drawn from freezer

Over run in ice cream

Size and shape of packages

Temperature of air in hardening room

Rate of air circulation in hardening room

Sections of the hardening room where the ice cream containers are stored.

Hardening time of 6- 8 hr may be considered normal for the operation to becompleted. However large containers may take more time as compared to smallpackages.

i. Hardening Methods: The following hardening methods are used for fasthardening of ice cream:

i) Hardening room: This is a low temperature cold store maintained at – 30°C or lower with large storing space. Also a good air circulation ismaintained throughout the room for uniformcooling effect.

ii) Hardening tunnel: This is a hardening room constructed in the form of aninsulated tunnel through which large volume of air is discharged. The aircirculated in the tunnel may be at –35 to – 40 °C and this helps in fasthardening of ice cream. Small blast tunnel hardeners mayalso be locatedin hardening room for faster hardening. Manufacturers of large volume ofice cream prefer to have this type of system.

iii) Hardening cabinet: This is a small, refrigerated cabinet maintained at –25°C or below. It may have two or more compartments separated fromeach other. Ice cream cups are tightly packed and stored in thesecompartments. This unit serves as hardening and storing cabinet. Thistype of unit is useful where volume of operation is low.

ii. Storage: After ice cream is hardened it is ready for sale. Until such time it ismarketed ice cream should be stored at temperature at which it is hardened.


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Hardening rooms or cabinet can be used as storage rooms for ice cream. Ifseparate storage room is used the following precautions should be taken:

i) Room temperature should be maintained uniformly (-11 to –15 °C)

ii) Ice cream packages should be piled very closely

iii) Cold air should be circulated uniformlythroughout the room

iv) Frequent opening and closing of the room should be avoided.

10.4 TRANSPORTATION OFFROZEN DESSERTS

When ice cream is ready for sale it is usually transported under refrigeration. Thetemperature shouldnot be allowed to rise as it causes ice cream to melt. Fine texturalqualityof icecream will be lost if the ice cream is allowed to melt andfreeze again inthe retailer’s cabinet.Adequate precautions should be taken while transporting theice cream to maintain low temperature. When it reaches the retailing point thetemperature of icecream should be thesame as is maintained in the retailer’s cabinet.The following methods are used for transportation of ice cream:

i) Refrigerated trucks: Insulated trucks fitted with mechanical refrigerationsystems are available for transportation of ice cream and other frozen desserts.These are like refrigerated storage rooms built on trucks bodies. Therefrigeration unit is operated by the power generated by the truck engine or byseparate generators fitted to the truck. Similar arrangements are also availableonrailwagons.Therefrigerated trucksor rail wagonsareused for transportationof largevolumeto longdistances. Icecreamis loadeddirectlyfromthehardeningroom/storageroominto these refrigerated trucks forvariousdistribution points.Temperature inside the refrigerated trucks is maintained byautomatic controlsprovided in the refrigeration system.

ii) Frozen brine: The freezing temperature of water is 0 °C. If some substanceslike salts are added to water the freezing point of solution will be lowered. Thesolution will not freeze at 0 °C but at a lower temperature depending upon theamount of salt added to water. The freezing point of the salt solution becomeslower as more salt is added until a certain limit is reached. The temperature atwhich freezingpointof the salt solution is not lowered bythefurther addition ofsalt is known as eutectic temperature. Calcium chloride solution of differentconcentration is used for preparation of frozen brine. Calcium chloride solution(brine) of specific gravity of 1.1 is filled in specially made jacketed metalcontainers known as eutectic pads. These pads are stored in low temperaturerefrigerated rooms or very low temperature brine tanks (-30 °C or below).The containers attain a temperature of –21 °C andare then removedand placedaround the packagedicecreamin insulatedcontainerfor transportation.Eutecticpads maybe fitted into trucks and vans where mechanical refrigeration systemisnotprovide. This systemofhavingeutecticpads forkeepinglow temperaturesduring transportation of ice cream can be used for shorter distances or forshorter duration.

Common salt mixed with plain ice is used in push-carts for keeping lowtemperature for sale of ice cream.

iii) Dry ice: Dryice is solid carbon dioxide with a freezingpoint of –78 °C. Smallpieces of dry ice wrapped in paper are placed around the package of icecreaminsideaninsulatedcontainer. If icecreamisproperlypackedwithsufficient


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dry ice it will maintain low temperature over longer period and this system ofshippingisuseful for longdistancetransport also.But therearesome advantagesas well as disadvantages of using dry ice.

Advantages:

Dry ice sublimes or passes directly to the vapour state. Hence there is nomoisture and water-logging in the insulation of the storage space.

It is light in weight.

Packaging with dry ice is easy and

Gives neat appearance.

Disadvantages:

It is expensive

Availabilityisalso limited

It should be handled with care as it may cause burns to the person who ishandling because of extremely low temperature

Theicecreammustbeun-packedorremovedfromdryicesufficientlyinadvanceto allow it to become softer so that it can easily be eaten.

Check Your Progress I

1. What are important requirements of packages for ice cream?

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2. Name the two types of packages used for ice cream.

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3. Name some ice cream types and frozen desserts which are first hardened andthen packaged.

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4. What do you mean by the term hardening of ice cream?

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5. Time required to complete hardening of ice cream depends on what factors?

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6. Which are different hardening systems used for hardening of ice cream?

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7. Name the methods used for transportation of ice cream.

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10.5 SENSORYATTRIBUTES

Sense of taste and odour is important in judging the quality of any product. Theproperties analyzed by these two senses along with the sense of touch largelydetermine the consumer’s acceptabilityof the product. Consumers of ice cream aregenerally interested in the healthfulness and the organoleptic properties of ice creamas determined bysenses of taste, odour and touch.Any change in the organolepticproperties will affect the consumer acceptability. It is therefore important to evaluateand judge the qualityof ice cream regularly to maintain the acceptable qualityof theproduct. Good quality ice cream should have the following properties:

An attractive package

Pleasant flavour

Smooth uniform bodyand texture

Melted ice cream should look like original ice cream mix

Uniformnatural colour

Low microbial count

i. Judging of Ice Cream

There are various methods available for evaluating the sensory characteristics ofdifferentdairyproducts.Anumerical scoringsystemisavailablebywhichit ispossibleto characterize the various attributes qualityof product and assign a numerical scorethat reflects both the seriousness of thedefect and its intensity.Asimplest scale wouldbe from 1 to 10 where 10 would be assigned to the product which is without anydefect and 1 would represent a verypoor quality product.American Dairy ScienceAssociation (ADSA) hasdeveloped score -cards for judgingdairyproducts includingice cream.The score-cardactuallyhas100points assigned todifferent characteristicsdepending on the product such as flavour, bodyand texture, appearance and colour,bacterial counts and container. The score card suggested for ice cream is given inTable10.1.

Table 10.1 Score card for Ice cram

Attributes Perfect scoreFlavour 45Body and Texture 30Colour and Apperance (Package) 05Melting quality 05Bacteria 15


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ii. Procedure of Examination:

i) Sampling:At random sample is taken from the ice cream storage.

ii) Tempering of ice cream: For judging of ice cream a temperature of –15 to–12 °C is satisfactory. Therefore, before judging the ice cream sample iskept in a dispensing cabinet for several hours before judging.

iii) Sequence of observations: The following sequence is followed duringjudging of the product:

a) Note the type and condition ofcontainer and presence ofanypackagedefects

b) Observe the colour of ice cream, its intensity and uniformity andwhether colour matches its flavour

c) While using a dipper for sampling, note the manner in which theproduct cuts, the evenness of cutting, the resistance offered duringcutting, the presence of ice particles, whether the ice cream is heavyorsoggy, lightor fluffy.Set asidea sample inapetri-dish forobservingthe meltingcharacteristics.

iv) Take a small spoonful of ice cream and taste it. Quickly manipulate thesample between teeth and tongue and note the body and texture andflavour characteristics.

v) Observe whether the melted ice cream in petri-dish is creamy, curdled,foamy or watery.

vi) Send the sample for determination of bacterial count in the laboratory

10.6 COMMON DEFECTSAND THEIR REMEDY

Defects may appear in ice cream due to following reasons:

Use of low quality ingredients

Improper mixingof ingredients

Faultymethod of manufacture

Faulty method of storage and transport

Qualityof ice cream is judged for its delicate and pleasing flavour, smooth bodyandtexture and attractive colour. The reasons for the development of defects in icecream and the preventive actions to be taken to remove the defects are discussed inthe following paragraphs.

i. Colour and appearance Defects and Preventive Measures:

i) Un-natural colour in ice cream develop due to following reasons:

Careless-ness in adding colour

Improper use of colour

Use of foreign materials

ii) Uneven colour results if the colour is not added and mixed properly.

iii) Excessive colour is due to addition of too much colour.


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To avoid any of the above colour defects in ice cream correct amount of colourshould be calculated, added and mixed thoroughly.Also the added colour shouldreflect the flavour characteristic of the ice cream. Cleanliness and neatness of thepakages should also be carefully observed.

ii. Melting quality defects and Preventive Measures

i) Curdy melt down or curdled melt down: It indicates high acidity in theice cream mix or the effect of anyother factor which causes instabilityofmilk proteins. This defect makes the consumer feel that inferior qualitymaterials were used in the preparation of ice cream. The defect may becorrected by:

Using fresh dairyproducts

Avoidinguse of anyproduct thatmight disturb natural salt balance ofthemix

Avoidingfreezingofhighacidmixes

ii) Ice cream does not melt: Ice cream shows resistance to melting, retainsshape whenwarmed and takes longer time to melt.Thecause and remedialmeasures of the defect are discussed under soggy body defecs.

iii) Slow meltdown: It indicates useof excessivestabilizer (over stabilization)or faultyprocessingof the mix. This condition maybe corrected bytakingthe followingmeasures:

Reducingamountof stabilizer


Homogenizing the mix at proper temperature and pressure

iv) Whey leakage: When ice cream melts separation of whey occurs. Thisdefectmayoccurduetopoorqualityof icecreammixor improperbalancingof mix. This defect can be corrected by:

Using good qualitydairyproducts

Balancing theconstituents carefully

Usingbetterqualitystabilizer

v) Foamy meltdown: This is caused by incorporation of too much air in theice cream during freezing (excessive over run). Hence the defect may becorrected byreducing the over run and reducing the amount of emulsifieror egg products.

iii. Body and texture defects and Preventive Measures

The bodyof ice cream refers to firmness and consistencywhile texture refers to thefineness of the product, which is dependent upon the number, size, shape andarrangement of ice crystals and other particles. The ideal body of ice cream is thatwhich is produced by the correct proportion of milk solids together with properover run and which melts fairly rapidly at room temperature to a smooth liquidsimilar in consistency and appearance to sweet cream containing about 40 % fat.

i) Crumbly body: It is a condition in which ice cream does not hold togetherproperly. It lacks cohesion or breaks apart veryeasily. It is associated with low


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total solids content, in-sufficient stabilization, excessive over run, imperfecthomogenization and large air cells. This defect can be remedied by:

Increasing the total solids content

Increasing the stabilizer

Decreasing the over run

ii) Soggy body: Ice cream with a dense bodyand wet appearance is an indicationof soggy body. It is due to a low over run, high concentration of sugar thatlowers the freezing point, excessive use of stabilizer or delayed packaging ofice cream after freezing. This defect is also similar to other defects such asgummy, doughy, sticky, pasty and gluey. Excessive stabilization or high totalsolids content produce a chewy or gummy body while certain types of gumsand syrups cause pasty or sticky body. Soggy body and other related defectscontribute to high melting resistance. These defects can be corrected by:

Maintaining correct over run

Reducing the quantityof stabilizer

Use of a combination of stabilizers

Reducing the sugar content

iii) Weak body: Ice cream lacks firmness or chewiness and is invariablyaccompanied by rapid melting. This defect is due to low total solids contentcombined with insufficient stabilization. This defect can be corrected by:

Increasing the total solids content

Adding correct amount of stabilizer

Properlyageing the mix

iv) Texture of ice cream: Ice cream having an ideal texture will be very smooth,i.e., the solid particles too small to detect in mouth.

v) Buttery texture: This defect appears in ice cream when lumps of butter- fataredetectedeasilyin themouth.Thisdefect isdue tohighfat content, inadequatehomogenization, mix entering the freezer at a higher temperature and partialchurning of cream due to slow freezing. This defect maybe corrected by:

Homogenizingthemix properly

Ageing themix properly

Freezing the mix quickly

vi) Coarse or icy texture: When the ice crystals are large or not uniform in sizeor that the air cells are too large in ice cream, icy texture is indicated. Thisdefect is most commonlynoticed in retailer’s shop. Large ice crystal formationin ice cream may be due to

Insufficientstabilizer

Slow freezing in the freezer

Slow freezing in the hardening room

Insufficientageingofmix


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Formation of large air cells may be due to:

Type of freezer used

Use of mix of low whippingability

Sometimes small ice particles are found in ice cream. These ice particles areformed when water droplets get into ice cream. This defect maybe eliminatedby

Increasing total solids in the ice cream

Increasing or adding correct amount of stabilizer

Freezingquicklyanddrawingicecreamata lower temperaturefromfreezer

Hardening ice cream quickly

Reducing storage period

Avoiding frequent heat shocks to ice cream

vii) Fluffy texture: This defect is due to presence of large amount of air cells. It isdue to incorporation of an excessive amount of air either as large or small aircells. This defect maybe expected when the total solids content in ice cream isnot more than one third of over run. When the air cells are large and the amountof air is excessive the texture is sometimes described as snowy or flaky. Thisdefect may be removed by

Decreasing over run

Increasing total solids

Decreasing theamount of emulsifiers

viii) Sandy texture: This defect is easily detected by the presence of rough sandlike particles in mouth when ice cream is tasted. This defect may be due topresence of more non-fat milk solids, which contribute more lactose. Higheramount of sugar may also lead to lactose crystallization. This defect can beeliminatedby

Reducing milk solids not fat content

Replacing part of cane sugar with other sweetening agents like dextrose,corn syrup etc

Maintaininguniformlylow temperature duringhardening and storage.

iv. Flavour Defects and Preventive Measures:

Ice cream flavour is essentiallya blendof flavours from different ingredients used inits preparation. The dairy products and flavouring materials used have profoundeffecton thedelicate flavourcharacteristicsof ice cream.Anydefect in thesematerialswill therefore influence significantlythe flavourof ice cream.

Defects due to flavouring materials:

i) High flavour: Excessof flavouringmaterial will impart a sharp bitter flavour inice cream. Poor qualityflavouringmaterial also imparts bitter flavour.This canbe corrected bychecking the qualityof flavouring materials and adding correctamount to get the desired delicate flavour.


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ii) Low flavour: It is due to insufficient amount of flavouring material. It requiresaddition of correct amount of flavouring material to overcome the defect.

iii) Harsh flavour: It is due to use of inferior flavouring substances. Thesesubstances or artificial extracts lack fine flavour .Also use of excess flavourcause this defect. Therefore correct quantity of superior flavours should beused.

iv) Acid flavour: This is caused by the presence of excessive amount of lacticacid. This can be corrected by:


Prompt and efficient coolingof mix

Avoiding prolonged storage of the mix at high storage temperature.

v) Bitter flavour: This defect may be caused by the use of inferior qualityingredients. The defect may be controlled by:

Using good / fresh extracts

Avoiding use of dairyproducts stored for long time at low temperature ascertain type of bacteria produce bitter flavour under these conditions.

vi) Cooked flavour: This is caused by over heating the mix or using over heatedconcentrated dairy products. The defect can be prevented by:

Carefullycontrollingpasteurization temperature

Using concentrated dairyproducts without cooked flavour

vii) Flat flavour: This results from the use of insufficient flavours, sugars or milksolids. Byadding required quantities of various ingredients this defect can becorrected.

viii) Un-natural flavour: This is indicated by the flavour not typical of ice cream.Thedefectcanbecontrolledbyusinggoodqualitydairyproductsandflavouringmaterials.

Synthetic flavours that are not correct imitation of true flavours are alsoconsideredun-natural.Similarlyflavoursdue topoorgelation, fermentedsyrups,over-ripe or under-ripe fruits and rancid nuts are un-natural. Therefore use ofsuch ingredients should be avoided to control this defect.

ix) Oxidized flavour: This defect is also known as tallowyor cardboard flavourandresults fromuseofoldorstoreddairyingredientsespeciallyfat richproducts.This defect can be remedied by use of fresh dairy products and pasteurizingthe mix at slightlyhigher temperature than recommended.

x) Shrinkage: Besides flavour and body texture defects one another defect isalsonoticedin icecream, especiallyin retail shops. Sometimeswhen well-filledpackages are hardened and stored, the volume of ice cream shrinks leavingspace either at the top or on the sides of the package. Cups then do not appearfull. This defect is known as Shrinkage defect. The main reason for this defectto occur appears to be excessive over run in ice cream and too much fluctuationin storage temperature. Maintaining constant temperature during storage andavoidingroughhandlingduringtransportationwillprevent thisdefect toagreaterextent in ice cream.


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Check Your Progress II

1. What are the desirable properties of good quality ice cream?

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2. What may be the reasons for defects to appear in ice cream?

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3. What maybe the reasons for un-natural or uneven colour in ice cream?

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4. What should be the consistencyof ice cream when it melts?

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5. How curdy melt down defect can be corrected?

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6. What is the reason for foamy meltdown?

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7. How crumbly body in ice cream can be corrected?

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8. What are the reasons for coarse or icy texture in ice cream?

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9. How sandy texture in ice cream can be removed?

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10. What may be the reason for bitter flavour in ice cream?

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10.7 LET US SUM UP

Ice cream is usually drawn from the freezer in containers, which give it the desiredshape or size for convenient handling during hardening. It is then transferred to avery low temperature room and stored until it is sold to the consumers. Thus, icecream is generallypackaged before hardening except for soft serve ice cream. Thepackaging material for ice cream should protect it against contamination, should beattractive, easy to open and reclose, easy to dispose apart from providing protectionagainst moisture loss or gain and temperature fluctuations. However, care should betaken to maintain deep freezer temperature duringhardening, storage, transportationandmarketingso that thequalityof icecreamismaintained till it reachestheconsumer.Ingeneral, icecreamshouldhaveauniformbody&texture,pleasant flavour,uniformcolourdistribution,optimumhardnessandmeltability,nobiggericecrystals formation,nosedimentsandoptimum overrun. Useof lowqualityingredients, improper mixingof ingredients, failure to formulate a balanced mix, faulty method of manufacture,improper packaging and faultymethod of storage and transport, failure to maintainoptimum cold chain etc., lead to the production of ice cream with defects. Thecommon colour and appearance defects are un-natural colour, uneven colour andexcessive colour. Flavour defects may be high flavour, low flavour, harsh flavour,acid flavour,bitter flavour, cookedflavour, flat flavour,unnatural flavourandoxidizedflavour. Body & texture defects include crumbly body, soggy body, weak body,butterytexture, fluffytexture, sandytexture, shrinkage and meltingdefects likecurdymelt down or curdled melt down, wheyleakage, foamymeltdown in ice cream doesnotmelt.

10.8 KEYWORDS

Hardening : is a continuation of freezing process withoutagitation inaverylow temperature room untilthe temperature of ice cream reaches –18°Cto –26°C.

Dry ice : is solid carbon dioxide with a freezing pointof –78°C and is used for transportation ofice cream.

Foamy meltdown : is a metl down defect in ice cream due toexcessive over run caused due to highincorporation ofair during freezing.

Crumblybody : is a condition in which ice cream does nothold together properly, lacks cohesion or


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breaks apartveryeasilydue to lowtotal solidscontent.

Soggy body : is a condition wherein the ice cream willexhibit a dense bodyand wet appearance dueto a low over run,highconcentration ofsugar,excessive use of stabilizer or delayedpackaging of ice cream after freezing.

Coarse or icy texture : is a texture defect, where large or irregularsizesof icecrystalsor too largeaircells appearin ice cream.

Sandy texture : is a texture defect, wherein rough sand likeparticles is felt in mouth when ice cream istasted due to presence of high level of non-fat milk solids and large size lactose crystals.

Shrinkage : is a condition, wherein volume of ice creamshrinks leaving space either at the top or onthe sides of the package when properly filledpackages are hardened and stored.

10.9 SOME USEFUL BOOKS

Outlines of dairy technologySukumar De Oxford Universitypress, Delhi

Ice cream W.S.Arbucle TheAVI publishing company, Inc. Westport ConnecticutUnited States OfAmerica

10.0 ANSWERS TO CHECK YOUR PROGRESS

Check Your Progress I

1. The important requirements of packages for ice cream are:

i. Protection against contamination

ii. Attractiveness

iii. Ease of opening and re-closure

iv. Ease of disposal

Desirable requirements are:

i. Protection against moisture

ii. Protection against temperature fluctuations

2. Multi- service and Single service

3. Brick ice cream, Chocolate coated ice cream, Ice cream sandwich Popciclesand water ices.

4. Hardening is continuation of freezing process. Freezing process is continuedwithout agitation in a very low temperature room until the temperature of icecream reaches –18 °C or below, preferably –26 °C. This process is calledhardening of ice cream.


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5. Time required tocomplete hardeningprocess depends on the followingfactors:

i. Initial compositionofmix

ii. Temperature of ice cream drawn from freezer

iii. Over run in ice cream

iv. Size and shape of packages

v. Temperature of air in Hardening room

vii. Rate air circulation in hardening room

viii. Sections of the hardeningroom where the ice cream containersare stored.

Hardening time of 6- 8 hr may be considered normal for the operation to becompleted. However large containers may take more time as compared tosmall packages.

6. Hardening room, Hardening tunnel and Hardening cabinet

7. Refrigerated trucks, Frozen brine/Eutectic pads in insulated vans, trucks orpush carts, Dry ice.

Check Your Progress II

1. Good quality ice cream should have the following properties:

i. An attractive package

ii. Pleasant flavour

iii. Smooth uniform bodyand texture

iv. Melted ice cream should look like original ice cream mix

v. Uniformnatural colour

vi. Low microbial count

2. Defects may appear in ice cream due to following reasons:

i. Use of low quality ingredients

ii. Improper mixingof ingredients

iii. Faultymethod of manufacture

iv. Faulty method of storage and transport

3. Un-natural colour in ice cream develop due to following reasons:

i. Careless-ness in adding colour

ii. Improper use of colour

iii. Use of foreign materials

4. Melted ice creamshould look like original ice cream mix. The idealbodyof icecreamis thatwhich is produced bythe correct proportion ofmilksolids togetherwith proper over run and which melts fairly rapidly at room temperature to asmooth liquid similar in consistencyand appearance tosweet cream containingabout 40 % fat.


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5. The defect may be corrected by:

i. Using fresh dairyproducts

ii. Avoiding use of anyproduct that might disturb natural salt balance of themix

iii. Avoiding freezingofhighacidmixes

6. This is causedbyincorporation of too much air in the icecream during freezing(excessive over run).

7. This defect can be remedied by:

i. Increasing the total solids content

ii. Increasing the stabilizer

iii. Decreasing the over run

8. Large ice crystal formation in ice cream maybe due to:

i. Insufficientstabilizer

ii. Slow freezing in the freezer

iii. Slow freezing in the hardening room

iv. Insufficient ageingofmix

9. This defect can be eliminated by:

i. Reducing milk solids not fat content

ii. Replacing part of cane sugar with other sweetening agents like Dextrose,corn syrup etc

iii. Maintaininguniformlylow temperature duringhardeningand storage.

10. The defect maybe caused by the use of inferior quality ingredients.

ice cream guide

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