Dairy and Milk Technology Session 8

Ice Cream

Lecturer: Ananditya Nugraha (anan)

Email: ananditya.nugraha@i3l.ac.id
 Related Learning Outcomes

• Explain and understand the Ice cream making

processes.
• Explain and understand important factors in Ice
cream making processes.
• Explain different type of Ice cream products.
• Explain factors attributing to the quality of Ice
cream products.
 Course Outline

• Type of Ice cream

• Ice Cream Processing
• Current Trends in Ice Cream products
Ice Cream
Ice Cream

ice + sugar
 Ice Cream
• Differences in Ice Cream”
– Soft Ice Cream (Stored in -3 to -5 degree Celsius) -> ready to eat ice cream

– Hardened Ice Cream (Stored in -25 degree Celsius) -> stored for a longer period

– Ordinary Ice Cream (Stored in -10 to -15 degree Celsius)

• Flavorings most often are needed in order to mask the rancidity

flavor.

• Pathogenic micro-organisms are immobilized but not killed,

particularly in soft ice cream -> Listeria monocytogenes.
texture: .....

overrun: how much air absorbed into fat globules

Ice Cream
• Standardize = To maintain the
content of milk solids-not-fat (protein,
lactose, minerals).
• Additives = Emulsifier, Stabilizer,
flavoring, coloring.
• Pasteurization =
– To inactivate pathogen micro-organisms.
– To inactivate “natural lipase” from the
milk.
– Bacterial lipase should be avoided.

• Homogenization =
– To give a smooth texture, large fat
globules will not produce “smooth” texture
– Excessive formation of homogenization
clusters should also be avoided as it
causes the mix to become highly viscous.
Ice Cream

Addition of Milk Solids non-fat and sugar in

the ice-cream making is important
“Freezing-point depression”

Lower the freezing point of the water, so

water can be frozen in a lower temperature
(below zero degree Celsius)

Of course it also meant to give a certain

texture
 too much: very hard

Ice Cream
Ice Cream

• Cooling and ripening is usually being done in

the Ageing tank (stirred as well).

• The mix must be aged for at least 4 hours at a

temperature of 2 to 5°C with continuous gentle
agitation.

• Ageing/Ripening allows the milk proteins and

water to interact and the liquid fat to crystallize.
This results in better air incorporation and
improved melting resistance.

• Certain stabilizers and emulsifiers need

considerable time to swell after being dispersed.
Ice Cream

• Freezing implies rapid cooling of the mix. It

freezes to a few degrees below zero in this way,
ice is formed while air is beaten in.

• This must run simultaneously in order to produce

the desirable quality (desirable over-run).
Ice Cream

• Hardening process serves to rapidly adjust the

temperature of the ice cream to such a level as
to retain its shape and to give it a sufficient shelf
life.
Ice Cream
Ice Cream
 Development of Ice Cream Product
• Adding IBP (Ice-Binding Protein) limit the ice- crystallization rate

• It has the capacity to bind the ice crystals significantly and reducing their
size while simultaneously inhibiting recrystallization.

• Usually IBPs are extracted from fish species

(https://doi.org/10.1016/j.foodchem.2017.10.152 )
Development of Ice Cream Product
Development of Ice Cream Product
Development of Ice Cream Product
Development of Ice Cream Product
Development of Ice Cream Product
Development of Ice Cream Product

W/O/W Multiple Emulsions

• Adding one more layer of emulsion

from the typical Water in Oil
emulsion.
• To retain functional properties of a
certain functional ingredients.
• “Encapsulating” the functional
ingredients so the functional
ingredients have better stability.
 Summary
• Ice cream -> Beating air into cream under low temperature.

• Factors that are important for Ice cream process:

– Sugar

– Fat crystallization

– Cooling rate

– Emulsifiers

• Different characteristics of Ice Cream with different purposes.

• Ice cream is a type of food products that can be further developed

for additional functional ingredients.
Dairy and Milk Technology Session 10

Butter

Lecturer: Ananditya Nugraha (anan)

Email: ananditya.nugraha@i3l.ac.id
 Related Learning Outcomes

• Explain the process of Butter making

• Explain the important factors in Butter making
– Raw Materials
– Processings
 Butter vs Margarine

15-20C apanya :)
Butter vs Margarine

• The basic material.

• The processing method.
– Butter = “Churning”
– Margarine =
Hydrogenation
 Butter
“Churning” process
Milk - Emulsion of would allow to
transform the
Oil in Water (O/W)
emulsion phase
and consequently
the form of the
product.

Butter - Emulsion of
Water in Oil (W/O)
 Important Factors
• Flavor -> Avoid lipolysis -> Rancidity
• Shelf-life -> off-flavor by microorganism
• Consistency -> depends on fat content and
temperature.
• Yield -> loss during skimming and churning
 Butter

• Churning = Churning in butter processing refers to the

mechanical process of agitating or stirring cream to
separate the butterfat from the liquid components in the
cream. This process is essential for the production of
butter from cream.
 Butter

• Working = Or can be referred to as kneading process is

done (1) to transform the butter grains into a continous
mass; (2) to finely disperse the moisture in the butter;
(3) to regulate the water content; and (4) if desired, to
incorporate salt.
 Butter

https://www.youtube.com/watch?v=VP54Pm33eJc

1. pasteurization & homogenization of milk (pasteurization: ensure milk apalah

ttg microbesnya yg harmful, homogenization: reduce creaming)
2. cool down
3. cream separation : centrifuge
4. churning
Butter

• The first part of butter processing is

Skimming process.
– Intended to minimize the fat loss percentage.
– Reduction of the size of the machinery used.
– Reduction of the volume of buttermilk produced
(minimize the by-products).

• Starter: produce lactic acid and “aroma”

compounds primarily diacetyl.
– Acid producers: Lactococcus lactis
– Aroma producers: Leuconostoc mesenteroides
Butter - Starter

aroma butter
Butter Process

• Ripening: sour the cream and to

crystalize the fat.

• Fat crystallization is important.

Without solid fat, churning is
impossible, and too little solid
fat goes along with excessive fat
loss in the buttermilk.
Churning Process

Traditional Churner
Churning Process
The rotation speed is about 500 and 300
rpm for about 1 minute.

Fat crystals will make the fats in the cream

to clumping together and make the “butter
grains”.
Butter Process

The size of the butter

grain is important, if the
butter grain produced is
very small, it will be
eliminated as well during
the washing process.
Churning Process
Butter Process

Cold storing the butter for

7 days at 10 degree
Celsius is intended to
make the butter firmer.
Butter Microstructure
 Fatty Acids for Butter

Size around 0.1 um – 20 um

(Average size: 3 – 4 um)
Fatty Acids for Butter
Choosing the correct type of fat
compositions is important for Butter
making.
• High content of short chain fatty
acid tends to give soft texture.
• High content of long chain
saturated fatty acid tends to give a
harder texture.
• Higher content of unsaturated
fatty acid tends to give a softer
texture
 Fatty Acids for Butter

Summer
Seasons

Winter – Spring
Seasons
Fall Seasons
 Fatty Acids for Butter
A B

A Processing parameters need to be adjusted

considering the fatty acids profile of the
milk products.
 Fatty Acids for Butter
A B

A
To maintain the consistency of the butter
products as well as the “Churning Yield”
 Fatty Acids for Butter

higher churning, higher

fat washed

• Churning recovery (yield) is a measure of how much of the fat in the cream has been converted to
butter. It is expressed in terms of the fat remaining in the buttermilk as a percentage of the total
fat in the cream.
• For example, a churning recovery of 0.50 means that 0.5 % of the cream fat has remained in the
buttermilk and that 99.5 % has been turned into butter. Churning yield is considered acceptable if
the value is less than 0.70.
 Summary
• Butter is a type of dairy products processed using churning technique in which the emulsion phase
is Water in Oil (W/O).
• Fat crystallization, addition of starter culture are important in maintaining the “churning” yield and
the flavors produced.
• Type of the fatty acids also contribute to the quality of the butters produced.
Dairy and Milk Technology Session 11

Yoghurt

Lecturer: Ananditya Nugraha (anan)

Email: ananditya.nugraha@i3l.ac.id
 Related Learning Outcomes

• Explain the process of making Yoghurt.

• Important Factors contributing the quality of

Yoghurt.

• Latest development in Yoghurt making.

 Yoghurt

applied in bread

higher fat content

 Yoghurt
• Fermentation product -> it is paramount to maintain
the quality of the milk itself.
• At the beginning, Yoghurt was discovered due to
spontaneous fermentation (no selection of the
starter culture).
• The lactic acid bacteria alter the conditions of the
milk in such a way that most undesirable organisms
cannot grow.
• Lactose is the main source -> preferable for lactose
intolerance consumers.
 Yoghurt
• Common starters used for Yoghurt processing:
Streptococcus thermophilus, Lactobacillus
delbrueckii ssp. bulgaricus.

• The starters produce Lactic acid, reducing the

pH value and forming casein network which
entraps the fat globule and forming gel
structure.
Yoghurt
Yoghurt
Yoghurt
 Metabolites of the Fermentation
process
• Lactic Acid

• Acetaldehyde (ethanal) -> Component is

essential for the characteristic of yoghurt
aroma.

• Diacetyl

• Polysaccharides -> Play an important role in the

yoghurt consistency.
 Set and Stirred Yoghurt
Set Yoghurt
Stirred Yoghurt
• Fermentation is
• Fermentation is
being done inside
being done
the retail
inside a big
packaging.
fermenter tank
• No stirring
• Stirring process
process.
• The consistency
• The consistency
of the yoghurt
of the yoghurt is
is smoother.
somewhat
firmer.
Drinking Yoghurt

Drinking Yoghurt

• For making drinking yoghurt, as the

texture has to be liquid additional
homogenization process is needed after
stirring process.

• High methoxyl pectin is also added after

stirring process -> prevent separation of
the drink -> Flavorings and sugars are also
can be added after stirring process.
Set and Stirred Yoghurt

• Yoghurt starter is the key

ingredient for processing
yoghurt products.
• Companies are routinely
developing starters for:
– Faster incubation time.
– Stronger gel-network produced.
– Better viability during storage->
probiotics.

• Preferred pH value is between

4.1 – 4.6
• Cooling down has to be quick
in order to stop the
fermentation process.
 Yoghurt Starter

Example of different type of Yoghurt starters increase the acidity

(reducing the pH) at a different rate.
 Homogenization and Heat Treatment

• Homogenization and Heat treatment conditions can affect the viscosity of the yoghurt
products.

• Homogenization and Heat treatment conditions depend on the desired quality of the
yoghurt produced.
Homogenization and Heat Treatment

Higher temperature increases the

deposition of serum protein onto the
surface of fat globules -> increasing
the gel-network bonding.
 Factors Affecting the Firmness of Set
Yoghurt
• Casein content of the milk -> adding skim-milk powder or partial
ultrafiltration can increase the firmness of Set Yoghurt.

• Un-homogenized Fat Content -> The higher the un-homogenized fat

content, the weaker the gel because the fat globules interrupt the
network.
 Syneresis of Yoghurt Products
Syneresis of Yoghurt Products

• Rearrangement of the gel-network in yoghurt product.

• Weak gel-network lead to expulsion of liquid entrapped in the gel-

network.

Factors affecting Syneresis

• Type of strains.
• Incubation temperature and
duration.
• Protein and Un-Homogenized
Fat content.
Syneresis of Yoghurt Products
 Seasonal Variations of Yoghurt
Products

As milk components can varying along the year. Manufacturers need to adjust
the processing parameters and conditions to meet the required product
specifications.
 Seasonal Variations of Yoghurt
Products

As milk components can varying along the year. Manufacturers need to adjust
the processing parameters and conditions to meet the required product
specifications.
 Beneficial Aspects of Yoghurt Products
• Lactose intolerance -> Lowered lactose content -> better for lactose
intolerance people.

• pH adjustment -> Consumption of fermented milk causes a smaller

increase of the pH of the stomach -> diminishes the risk of passage of
pathogens.

• Probiotics and prebiotics-> Beneficial to improve the gut microflora.

 Summary

• Mainly there are three type of Yoghurt Products:

– Set Yoghurts

– Stirred Yoghurts

– Yoghurt Drinks.

• Incubation, Homogenization, Heat treatment, are important to reach the

desirable strong gel network -> prevent syneresis (most common physical
defects) -> Preferred Yoghurt consistency.

• Casein and Un-homogenized fat content of milk play important roles in

the gel-network of the Yoghurt.

• Yoghurt could give beneficial aspects for human consumption.