Ice cream is a popular dairy product among consumers of all ages. Textural of ice are the key factors of the product. It is a microcrystalline network of liquid and solid phases. It contains air cells entrapped in liquid phase and various other components like proteins, fat globules, stabilizers, sugar, soluble and insoluble salts are also present in this phase. It is a complex physicochemical and colloidal system consisting on many complex ingredients that affect ice cream structure both in positive and defective functionality. Both stabilizers and emulsifiers improve the texture of ice cream by enhancing its viscosity and limiting the movement of free water molecules but their excess may cause the lower melting and less whipping ability. As sugar provides sweet taste, improves thickness as well as bulkiness but on other hand its excessive use can turn ice cream into soggy structure. One of its compositional contents, fat, also exerts good effects on body, texture, palatability, flavor intensity, emulsion formation and maintenance of melting point. If fat contents exceed a specific usage concentration, they cause faster meltdown of ice cream along with destabilization and agglomeration of fat droplets. Higher overrun results in collapsing of air cells ultimately shrinkage of structure occurs. Hardness might also reduce as a result of smaller ice crystals due to high overrun values. Fiber addition causes the binding of free water hence flow rate gets reduced and consistency coefficient as well as viscosity enhanced. Binding of water results in less availability of its molecules; freezing point rises and melting point decreases. It is much critical to control the balance ice cream properties by maintaining its structure, texture and body based on chemistry of different ingredients and processing effects.

1. Ramani Akshay R.
Dairy Chemistry Division
Chemistry of Ice cream

2. Content
• Introduction
• FSSAI Standards
• Ice cream Microstructure
• Emulsifier
• HLB concept
• Stabilizer
• Effect of processing parameter on Ice-Cream
• Modern Approach
• Defects in ice cream related to emulsion
• conclusion

3. India is the largest producer and marketer of milk.
Ice cream is a popular dairy product among consumers of all ages.Ice cream
contributes energy of ~ 220 kcal/100 g and is a rich source of nutrients.
The ice cream market in India is forecast to exhibit a CAGR of 17.03% during
2016-2021. India produced more than 200 million liters of ice cream in the
financial year 2020.
Introduction
(Goff et al., 2013)

6. According to FSSAI (2011) Ice Cream, Kulfi, Chocolate Ice Cream or Softy Ice Cream
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/fruit products, eggs/egg products, coffee, cocoa, chocolate, condiments,
spices, ginger and nuts. It may contain cake or cookies as a separate layer and/or coating.
The product may be frozen hard or frozen to a soft consistency and shall possess a
pleasant taste and smell free from off flavour and rancidity.
FSSAI definition of Ice cream
- FSSAI (2011)

7. 7
Sr.
No.
Requirements
Ice cream category
Regular
Medium
fat
Low fat
1. Milk fat (%), Min. 10.0 2.5-10 2.5
2. Milk protein (%), Min. 3.5 3.5 3.0
3. Total solids (%), Min. 36.0 30.0 26.0
4. Weight/volume (g/lit.), Min. 525 475 475
Food Safety and Standards for Ice cream
- FSSAI (2011)

18.  Emulsifiers act as surface active agents and reduce the energy
required to maintain the integrity of the fat globules.
 Added emulsifiers are more effective than milk proteins due to their
smaller molecular size and greater mobility.
 Function of emulsifiers is to destabilize the fat globule. This permits
a degree of clustering and prevents too rapid melting.
Emulsifier
- (Bahramparvar et al., 2011)

20. - (Bahramparvar et al., 2011)

21.  The HLB (hydrophilic–lipophilic balance) concept is used for describing
the nature of the surfactant.
 It is based upon the relative percentage of hydrophilic to lipophilic groups
within the emulsifier molecule.
 Griffin assigned values ranging from 0 to 20 (Waginaire et al., 1997).
 Glycerol Mono Stearate (GMS) has got a HLB number of 3 whereas
polysorbate 65 has got a HLB number of 13.
HLB concept
 Materials having an:
 HLB value (3-6) are lipophilic & produce W/O.
 HLB value (9-12) are hydrophilic and produce O/W

22.  Promote nucleation of fat during aging thus reducing aging time
 Improve the whipping ability
 Produce a dry and stiff ice cream
 Increase resistance to shrinkage and rapid melt down
 Increase resistance to the development of coarse/icy texture.
 Provide smooth texture in the finished product
Role of emulsifiers in ice cream
- (Bahramparvar et al., 2011)

23.  The stabilizers are a group of compounds, usually polysaccharides.
 The ice cream would become coarse and icy very quickly Without
stabilizers.
 Good ice cream products can be made with only the natural
stabilizing and emulsifying materials present in milk such as milk
proteins and phosphates, additional stabilizers have potential
benefits.
Chemistry of stabilizer
-(Goff et al., 2013)

24.  Most stabilizers are polysaccharides of plant origin
 Alginates and carrageenans (from seaweeds)
 Locust bean gum and guar gum(from tree seeds)
 Pectin (from fruit)
 Sodium carboxymethyl cellulose (from cotton).
 Xanthan, (a bacterial polysaccharide)
 Gelatin, (a polypeptide of animal origin.)

25.  To increase the viscosity of the mix.
 To stabilize the mix i.e. To prevent wheying off .
 To produce a stable foam with desired stiffness at the time of
packaging .
 To reduce or slow down the growth of lactose crystals during
storage mainly during temperature fluctuations .
 To reduce moisture migration from the product to the package or
the air .
 To help prevent shrinkage of the product volume during storage .
 To provide uniformity to the product and resistance to melting .
 To produce smoothness in texture during consumption .
Role of Stabilizers in ice cream
-(Goff et al., 2013)

26.  Stabilizers are functionally work as hydrocolloids.
 The most apparent effect of stabilizers is the increased viscosity of
the continuous liquid phase.
 The effect of stabilizers on viscosity exhibits considerable
interaction with milk constituents.
 During hardening, the water content of ice cream falls considerably
with a associated increase in the concentration of stabilizer in the
liquid phase (increases the viscosity)
Mechanism of action

27.  The movement of water is partly block by the ability of
hydrocolloids to form hydrogen bonds. Thus, refreezing of water
that originated from melting of ice due to temperature fluctuations
would not permit the formation of large ice crystals.

28. Effect of processing parameter on Ice-Cream

29. Flow diagram for the production of ice cream

30.  The main role of pasteurization is to ensure the microbiological
safety of the product, the heating also affects the physico-
00chemical structure of the mix.
 The emulsifier is melted and heat-activated stabilizers brought into
colloidal solution.
 The whey proteins present in the SNF are partially denatured and
uncoil exposing the lipophilic portion of the molecule.
Effect of pasteurization
-(Varnam et al., 1994)

31.  Denaturation also increases the number of available binding sites
for protein: hydrocolloid interactions and thus enhances the action
of stabilizers such as carrageenan.
 Pasteurization is generally beneficial to ice cream quality, but
excessive heat treatment leads to unacceptable organoleptic
deterioration.

32.  During ageing a number of important changes occur.
 Skim milk powder and stabilizers become fully hydrated and the
emulsifier-induced desorption of proteins continues.
 Substantial crystallization of fat also occurs. Triacylglycerols of the
highest melting point are the first to crystallize and are situated
closest to the surface of the fat globules.
 The crystallization process continues successively with
triacylglycerols of progressively lower melting points, creating
multiple-shelled fat globules with a core of liquid fat.
Effect of ageing
Varnam
-(Goff et al., 2013)

34. This process causes the emulsion to undergo partial
coalescence or fat destabilization, during which clumps
and clusters of the fat globules form.
Whipping

35.  Overrun is usually defined as the volume of ice cream obtained
in excess of the volume of mix, and is expressed as percent
overrun
Overrun
Packaged ice cream 70-75%
bulk ice cream 90-100%
Super premium ice cream 30-50%
Sherbet 30-40%
milk shakes 10-50%

36.  Fat globules in ice cream mix are of two types, large globules
ranging in size from 0.5 to 4 µm, but with most less than 2 µm
diameter, the overall mean being ca. 1 µm.
 In addition very fine globules are also present which range in
diameter from 0.04 to 3 µm with a mean diameter of 05 µm.
 Destabilization of the fat emulsion, initiated by the action of
emulsifiers, continues as a result of the combined effects of
freezing and mechanical agitation during the freezing process.
freezing process
-(Goff et al., 2013)
- (Bahramparvar et al., 2011)

37. Destabilization of fat globules during freezing.

38. Internal structure of ice cream.
(a) Ice crystal
(b) Ice crystals
(c) Unfrozen material
-(Varnam et al., 1994)

39. Wall separating ice crystals
-(Varnam et al., 1994)

41. 41

42. Anti-freezing protein
 Anti-freeze blood proteins found in deep sea species, e.g. Arctic ocean
pout fish, and this anti-freeze protein is grown in vats using GM yeast.
 At only 0.01% concentration, this synthetic protein lowers the temperature
at which ice crystals form and also affect their shape and it allows
Unilever to make a thick, creamy 'low-fat' ice cream and this such ice
cream is already on sale in the USA.
(Kaleda et al., 2018)

43. conclusion
• It is better to see the future of ice cream. Unilever has
used genetic modification (GM) technology to make
synthetic analogues of naturally-occurring anti-freeze
blood proteins found in deep sea species.
• Restructuring casein micelles in ice cream mix with HPP
is an interesting technology for improving textural
properties of ice cream.
• It is much critical to control the balance ice cream
properties by maintaining its structure, texture and
body based on chemistry of different ingredients and
processing effects.

44. Thank you