ice cream namratha kollu - agrihortico · 2019. 12. 10. · ice cream • ice cream, kulfi,...
TRANSCRIPT
ICE CREAM
Namratha Kollu
Ice cream
• Different kinds of frozen deserts.
1. Dairy ice cream
2. Non dairy ice cream
3. Gelato
4. Frozen yoghurt
5. Milk ice
6. Sorbet
7. Sherbet
8. Water ice
9. Fruit ice
Ice cream
• Frozen Dessert / Frozen Confection(hereafter referred to as the said product) means the product obtained by freezing a
pasteurized mix prepared with milk fat and / or edible vegetable oils and fat having a melting point of not more than 37.0
degree C in combination and milk protein alone or in combination / or vegetable protein products singly or in combination
with the addition of nutritive sweetening agents e.g. sugar, dextrose, fructose, liquid glucose, dried liquid glucose,
maltodextrin, high maltose corn syrup, honey, fruit and fruit products, eggs and egg products coffee, cocoa, chocolate,
condiments, spices, ginger, and nuts. The said product may also contain bakery products such as cake or cookies as a separate
layer/or coating, it may be frozen hard or frozen to a soft consistency. It shall have pleasant taste and flavor free from off
flavor and rancidity and may contain food additives permitted
Ice cream
• Ice Cream, Kulfi, Chocolate Ice Cream or Softy Ice Cream(hereafter referred to as the said product) means the product
obtained by freezing a pasteurized mix prepared from milk and /or other products derived from milk with or without the
addition of nutritive sweetening agents, fruit and fruit products, eggs and egg products, coffee, cocoa, chocolate, condiments,
spices, ginger and nuts and it may also contain bakery products such as cake or cookies as a separate layer and/or coating.
The said product may be frozen hard or frozen to a soft consistency; the said product shall have pleasant taste and smell free
from off flavour and rancidity; the said product may contain food additives permitted
Ice cream
"ICE LOLLIES OR EDIBLE ICES" means the frozen ice produce which may contain sugar, syrup, fruit, fruit
juices, cocoa, citric acid, permitted flavors and colors. It may also contain permitted stabilizers and/or emulsifiers not
exceeding 0.5 per cent by weight. It shall not contain any artificial sweetner. Ice Candy means the product obtained by
freezing a pasteurized mix prepared from a mixture of water, nutritive sweeteners e.g. sugar, dextrose, liquid glucose,
dried liquid glucose, honey, fruits and fruit products, coffee, cocoa, ginger, nuts and salt. The product may contain food
additives permitted
It shall conform to the following requirement:—
Total sugars expressed as Sucrose ... Not less than 10.0 percent
• All the definitions are taken from the FSSA, ACT
Different classification of ice creams
Component Economy Standard Premium Super premium
Fat Legal Minimum usually 8-10% 10-12% 12-15% 15-18%
Total solids Legal Minimum usually 35-36% 36-38% 38-40% >40%
Over run Legal Maximum 100-120% 60-90% 25-50%
Ice cream
Different Ingredients in Ice cream and their functions and limitations
Constituent Functions Limitations
Milk Fat Increases the richness of flavor Relatively high cost
Lubricates and insulates the
mouth Smoothness of texture hinders whipping
May limit the consumption due to high calories and satiating effect
Non Dairy Fats
Provides good structure and
texture at lower cost than milk fat,
if appropriate solid fat content Contributes little to flavor and may impart the off flavors
May contribute to greasy texture
Milk solids not fat
Improves the body and texture
through emulsification and water
holding capacity High content may cause cooked or salty flavor
Whey protein
concentrates Promotes development of overrun Potential for sandiness (lactose crystallization) at high concentration
Whey solids
Less expensive than the
conventinal sources of MSNF High amount of lactose causes freezing point depression
Potential for sandiness greater than for conventional sources of MSNF
Different Ingredients in Ice cream and their functions and limitations
Constituent Functions Limitations
Sugar Lowers freezing point Excess sweetness possible
Imparts sweetness to the ice
cream Lower hardening temperature needed
Improves flavor/texture
Ice cream is softer , affecting scooping and the potential for greater
recrystallization
Corn syrup solids Lower cost than sugar Impart off flavor and chewy texture when overused
Improve body and texture
Increase the stability of ice cream
Stabilizer Enhance smooth texture Excess chewiness may occur
Provide body Increase the melt resistance
Enhance shelf life
Egg yolk solids Improve whipping ability Foamy melted product
Impart the custard flavor Egg flavor may be undesirable
Emulsifiers
Promote fat destabilization,
leading to dryness, smoothness
and good melting properties Increase potential for churning of fat
Different Ingredients in Ice cream and their functions and limitations
Constituent Functions Limitations
Total solids Smoother texture Heavy, soggy or sticky body
Firmer body Reduces coldness
High nutrient content
Lessen excess coldness
Flavoring Increases acceptability Intensities and harshness may be unacceptable
Coloring Improves attractiveness Artificial shades
Aids Flavor identification Allergic reactions
Dislike of consumers to added colors
Schematic diagram of ice cream processing:
Flow chart of ice cream processing
Points to be noted for mix
• MILK SOLIDS-NON-FAT (MSNF)
• MSNF consist of proteins, lactose and mineral salts
derived from whole milk, skim milk, condensed milk,
milk powders and/or whey powder. In addition to its
high nutritional value, MSNF helps to stabilize the
structure of ice cream due to its water-binding and
emulsifying effect. The same effect also has a
positive influence on air distribution in the ice cream
during the freezing process, leading to improved
body and creaminess.
In a well-balanced recipe, the quantity of MSNF
should always be in proportion to the water content.
The optimal level is 17 parts MSNF to 100 parts
water:
Standard formulations
The Mix Process:
High shear and High temperature(85 degree centigrade)
Formation of mix involves 3 major processes
1. Dispersion- High shear
2. Hydration of dry ingredients - High temperature
3. Emulsification
Ice cream
Ice cream
Order of addition :
1. Potable water
2. Emulsifier and stabilizer mix + sugar
3. Proteins
4. SMP
5. Remaining Sugar
6. Liquid Glucose
7. Fat
Ice cream
Double stage Homogenization Individual Homogenization
Homogenization:1. Stable suspension
2. Reduction of particle size of fat
• In the homogenizer the hot mix (> 70 C) is forced through a small valve under
high pressure (typically up to about 150 atm). The large fat droplets are
elongated and broken up into a fine emulsion of much smaller droplets (about
1 pm in diameter), greatly increasing the surface area of the fat.
• Sometimes a second homogenization step is used with a lower pressure
(about 35 atm) to reduce clustering of the small fat droplets after the first
stage.
• Recently, very high pressure homogenization (up to 2000 atm) has been
shown to produce even smaller fat droplets, and therefore a higher fat surface
area for a given volume.
• Proteins are very good at stabilizing oil-in-water emulsions against
coalescence because they provide a strong, thick membrane around the fat
droplet. Interactions between the proteins on the outside of the droplets make
it harder for the droplets to come into close contact. This is known as steric
stabilization.
Homogenization
Pasteurization:Minimal Time and Temperature combinations for ice cream mixes:
Source:Grade A Milk ordinance FDA , 2011
Ice cream
Ice cream
Schematic diagram of Pasteurization in Plate Heat Exchanger
Aging:
1. Temperature – 4 degree centigrade
2. Time - 4 hours to 24 hours.
•Emulsifiers adsorb to the surface of the fat droplets replacing
protein
•Crystallization of the fat
•Continuous re arrangement of the fat globules to form a
structure.
Ice cream
Freezing:Ice cream mix at approximately 4 degree C is pumped from the ageing
tank into the barrel, where it is aerated and frozen, before being pumped
out from the other end.
Ice cream
Cup filling
Cone filling
Cup and cone products:
Ice cream
Moulded Products:
Ice cream
Ice cream
Extruded Products:
Ice cream
New Developments in Vertical Extrusion:
Ice cream
Hardening:
•Quick hardening : -18 degree centigrade or preferably -25 degree
centigrade.
Ice cream
Qualitycontrolof ice creams
% Overrun = (Vol. of ice cream - Vol. of mix used)/Vol. of mix used x 100%
Example : 500 L mix gives 980 L ice cream,
(980 - 500)/500 x 100% = 96% Overrun
80 L mix plus 10 L chocolate syrup gives 170 L chocolate ice cream,
(Note : any flavors added such as this chocolate syrup which become
homogeneous with the mix can incorporate air and are thus accounted for in
this way : )
(170 - (80 + 10))/(80 + 10) x 100% = 88.8% Overrun
Over run:
Figuring plant overrun by volume, with particulates
Example : 40 L mix plus 28 L pecans gives 110 L butter pecan ice cream,
110 - 28 = 82 L actual ice cream.
% Overrun = (Vol. of ice cream - Vol. of mix used)/Vol. of mix used
= (82 - 40)/40 x 100% = 105%
(Note : The pecans do not incorporate air.)
Over run in presence of nuts:
Qualitycontrolof ice creams
Figuring density of mix:
Qualitycontrolof ice creams
Figuring mix density
The density of mix can be calculated as follows:
1 / ((% fat/100 x 1.075) + ((% T.S./100 - % Fat/100) x 0.63) + (% Water/100)) = Wt.
(kg)/ litre mix
Example - Calculate the weight per litre of mix containing 12% fat, 11% serum
solids, 10% sugar, 5% corn syrup solids, 0.30% stabilizer, and 38.3% T.S.
1.0 / ((0.12 x 1.075) + ((0.383 - 0.12) x 0.63) + 0.617) = 1.096 kg/L of mix
•Flavor defects
•Body and texture defects
•Melting Quality characteristics
•Color defects
•Shrinkage
Defects in ice creams
Flavoring System
Unnatural flavor - Caused by using flavors that are not typical of the
designated flavor i.e. wintergreen flavor on vanilla ice cream. esp. vanillin
Egg: Caused by using too much egg in an ice cream that is not specified as a
custard ice cream - resembles French vanilla ice cream .
Defects in ice creams
Processing:
Cooked: Caused by using milk products heated to too high a temperature or
by using excessively high temperatures in mix pasteurization. It can dissipate
with time, the same as cooked defect in fluid milk. Sulfhydryl flavor: Caramel-
like, scalded milk, oatmeal-like.
Dairy Ingredients
High Acid: Use of dairy products with high acidity (usually due to bacterial
spoilage) or holding mix too long and at too high a temperature before freezing.
Acid/sour flavours are more rare these days due to the growth of proteolytic
psychrotrophs during storage at elevated temperatures, rather than lactic acid
bacteria.
Salty: Ice cream too high in milk solids-not-fat. Too much salt may have been
added to the mix. High whey powder, or maybe salted butter used instead of
sweet butter.
Defects in ice creams
Old Ingredient: Caused by the use of inferior dairy products in the preparation
of the mix. Powders made from poor milk or stored too long at elevated
temperature or butter made from poor cream will contribute to old ingredient
flavor. Unpleasant aftertaste.
Oxidized: Caused by oxidation of the fat or lipid material such as phospholipid,
similar to fluid milk oxidation. Induced by the presence of copper or iron in the
mix or from the milk itself. Mono-and-di-glyceride or Polysorbate 80 can also
oxidize. Various stages - cardboardy, metallic (also described as painty, fishy).
Rancid: Caused by rancidity (high level of free butyric acid from lipolysis) of
milk fat. May be due to use of rancid dairy products (pumping or excessive
foaming of raw milk or cream) or to insufficient heat before homogenization of
mix. See description of Lipolysis, especially the release of free butyric acid.
Defects in ice creams
Coarse/Icy Texture: Due to the presence of ice crystals of such a size that
they are noticeable when the ice cream is eaten.
May be caused by:• Insufficient total solids (high water content).
• Insufficient protein.
• Insufficient stabilizer or poor stabilizer.
• Insufficient homogenizing pressure (due to its effect on fat structure formation).
• Insufficient aging of the mix (stabilizer hydration, also fat crystallization and
development of resulting fat structure).
• Slow freezing because of mechanical condition of freezer.
• Incorporation of air as large cells because of physical characteristics of mix or type of
freezer used.
• Slow hardening.
• Fluctuating storage room temperatures.
• Rehardening soft ice cream.
• Pumping ice cream too far from continuous freezer before hardening.
• Fluctuating temperatures during storage and distribution - the most likely cause! See
discussion of ice cream shelf life.
Defects in ice creams
Crumbly Body: A flaky or snowy characteristic caused by:
• High overrun together with large air cells.
• Low stabilizer or emulsifier.
• Low total solids.
• Low protein.
Fluffy Texture: A spongy/marshmallowy characteristic caused by:
• Incorporation of large amount of air.
• Low total solids.
• Low stabilizer content.
Gummy Body: This defect is the opposite of Crumbly in that it imparts a pasty
or putty-like body. It is caused by:
• Too low an overrun.
• Too much stabilizer.
• Poor stabilizer.
Defects in ice creams
Sandy texture: One of the most objectionable texture defects but easiest to
detect. It is caused by Lactose crystals, which do not dissolve readily and
produce a rough or gritty sensation in the mouth. This can be distinguished
from "iciness" because the lactose crystals do not melt in your mouth. This
defect can be prevented by many of the same factors that inhibit iciness:
• hardening the ice cream quickly
• maintaining low storage room temps.
• preventing temperature fluctuations...from manufacturer to consumer
Weak Body: Ice cream lacks "chewiness" and melts quickly into a watery
liquid. Gives impression of lacking richness. May be caused by:
• Low total solids.
• High overrun.
• Insufficient stabilizer.
Melting Quality Characteristics
1. Curdy Melt-Down: May be due to visible fat particles or due to coagulation of
the milk proteins so is affected by factors that influence fat destabilization or the
protein stability such as:
•High acidity (protein coagulation).
•Salt balance (protein coagulation).
•High homogenizing pressures (fat coagulation).
•Over-freezing in the freezer (fat coagulation).
2. Does not Melt: May be caused by:
•Over emulsification.
•Wrong emulsifier.
•High fat.
•Excessive fat clumping in the mix due to homogenization at too low a
temperature or single-stage homogenizer.
•Freezing to too low a temperature at freezer.
3. Wheying off: The salt balance, protein composition, and carrageenan addition
(or lack or it) all are factors.
Defects in ice creams
Color DefectsColor Uneven: Applies usually to ice cream in which color has been used, but may be
noticed in vanilla ice cream under some circumstances.
Color Unnatural:
• Wrong shade of color used for flavored ice cream.
• Too much yellow coloring used in vanilla ice cream.
• Grayish color due to neutralization.
ShrinkageA very troublesome defect in ice cream since there appears to be no single cause or
remedy. Defect shows up in hardened ice cream and manifests itself in reduced volume of
ice cream in the container usually by pulling away from the top and/or sides of container.
Structurally, it is caused by a loss of spherical air bubbles and formation of continuous air
channels. Some factors believed associated with the defect are:
• Freezing and hardening at ultra low temperatures.
• Storage temperature. Both low and high appear to contribute.
• Excessive overruns.
• Pressure changes, for example, from altitude changes (lids popping when shipped to
high altitudes, shrinkage when returned to low altitudes).
Defects in ice creams
References
• The Science of Ice cream, C.Clarke
• Ice cream, Rich Hartel and Douglas Goff
• Dairy Processing Handbook
Thank you
Presented by : Namratha Kollu