This document provides information about milk processing operations. It begins with an introduction to milk and its composition. The main constituents of milk are water, milk fat, milk proteins, milk sugar (lactose), enzymes, vitamins, and minerals. It then describes common milk processing operations like pasteurization, homogenization, and cream separation. Pasteurization involves heating milk to high temperatures to eliminate harmful bacteria. Homogenization breaks down milk fat globules for a creamier texture. Cream separation separates milk into cream and skim milk using gravity or centrifugal force. The document also discusses standardization, mixing ingredients, and properties of milk.

2. BANARAS HINDU
BANARAS HINDU
UNIVERSITY
UNIVERSITY
Centre of Food Science &
Centre of Food Science &
Technology
Technology

3. MILK
MILK
PROCESSING
PROCESSING
SUBMITTED TO:
Dr. R. C. Pradhan
Asst. Professor
Dept. of
Agricultural
Farm Engineering
SUBMITTED BY:
SUBMITTED BY:
Sukhveer Singh
Sukhveer Singh
Prabal Pratap Singh
Prabal Pratap Singh
Uday Pratap Singh
Uday Pratap Singh

5. -:INTRODUCTION:-
Milk is a unique in that it is both consumed,
as fluid milk with minimal processing and it is the raw
material used to manufacture a wide variety of
product.
Definition
Milk may be defined as the whole, fresh, clean, lacteal
secretion obtained by the complete milking of one or
more healthy milch animals, excluding that obtained
within 15 day before or 15 days after calving or such
periods as may be necessary to render the milk
practically colostrums-free and containing the
minimum prescribed percentages of milk fat and
milk-solid-not-fat.

6. -:MILK AND ITS COMPOSITION:-
Milk
Water Total solid
Fat Solid not fat (SNF)
True fat Associates substance
Phospholipids Cholestrol Carotene Vitamin
(A, D, E, K)
Lactose Nitrogeneous Mineral Other
Substance Constituents
Non Protein Protein
Casein Lactalbumin Lactoglobulin Protease-peptone
Pigments Dissolved gases Vitamin (B,C) Enzymes bacteria

7. WATER
WATER
Largest fraction of milk & ranges from 80-90%.
Largest fraction of milk & ranges from 80-90%.
Serves as carrier for other constituents of milk.
Serves as carrier for other constituents of milk.
MILK FAT
MILK FAT
The Milk fat exists in the form of small globules, which
The Milk fat exists in the form of small globules, which
averages approximately 2-5 microns in size.
averages approximately 2-5 microns in size.
Milk fat is rich source of energy & good source of vit.
Milk fat is rich source of energy & good source of vit.
A & D.
A & D.
% of milk fat varies in different animals & their
% of milk fat varies in different animals & their
varities.
varities.
It may ranges from 1-13%.
It may ranges from 1-13%.

8. MILK PROTIEN
MILK PROTIEN
Milk normally contains about 0.5% of nitrogen of
Milk normally contains about 0.5% of nitrogen of
which 95% constituents milk protein & 5% non
which 95% constituents milk protein & 5% non
protein nitrogen.
protein nitrogen.
Casein is phosphoprotien, accounts for 80% of
Casein is phosphoprotien, accounts for 80% of
total protein content.
total protein content.
The viscosity & white colour of milk are largely
The viscosity & white colour of milk are largely
because of casein.
because of casein.
MILK SUGAR OR LACTOSE
MILK SUGAR OR LACTOSE
It occurs exclusively in mammalian milk.
It occurs exclusively in mammalian milk.
The average lactose content of cow & buffalo milk
The average lactose content of cow & buffalo milk
is 4.5 & 4.8% respectively.
is 4.5 & 4.8% respectively.

9. ENZYMES
ENZYMES
A number of enzymes present in milk. More than
A number of enzymes present in milk. More than
25 enzymes have been identified in cow milk.
25 enzymes have been identified in cow milk.
The milk enzymes are of considerable importance
The milk enzymes are of considerable importance
in certain aspects of milk technology. For example
in certain aspects of milk technology. For example
lipase is responsible for the development of rancid
lipase is responsible for the development of rancid
flavours in milk.
flavours in milk.
VITAMINS
VITAMINS
Milk is good source of fat soluble (Vitamins A,D,E
Milk is good source of fat soluble (Vitamins A,D,E
& K) & water soluble vitamins (B).
& K) & water soluble vitamins (B).
Milk is good source of Vitamin A but it is poor
Milk is good source of Vitamin A but it is poor
source of Vitamin C.
source of Vitamin C.
MINELRALS
MINELRALS
Milk is an important source of calcium, potassium,
Milk is an important source of calcium, potassium,
phosphorous & magnesium.
phosphorous & magnesium.

10. Properties of Milk
Properties of Milk
1. Physical state of Milk:
1. Physical state of Milk: The Milk constituents exists
The Milk constituents exists
partially as a solution & partially in colloidal state.
partially as a solution & partially in colloidal state.
2. Acidity of Milk:
2. Acidity of Milk: The titratable acidity of milk is usually
The titratable acidity of milk is usually
expressed as lactic acid equivalent per 100 ml. of milk & it
expressed as lactic acid equivalent per 100 ml. of milk & it
may range from 0.13 – 0.21%.
may range from 0.13 – 0.21%.
3. pH of Milk:
3. pH of Milk: Milk is slightly acidic in nature & its ph
Milk is slightly acidic in nature & its ph
value varies from 6.5 – 6.7.
value varies from 6.5 – 6.7.
4. Colour of Milk:
4. Colour of Milk: Milk ranges in colour from yellowish
Milk ranges in colour from yellowish
creamy to creamy white. The larger the fat globules & the
creamy to creamy white. The larger the fat globules & the
higher the fat percentage , the greater intensity of the yellow
higher the fat percentage , the greater intensity of the yellow
colour.
colour.

11. 5. Flavour:
5. Flavour: This is composed of smell (odour) & taste.
This is composed of smell (odour) & taste.
Milk is sweet in taste. The chlorides & lactose are
Milk is sweet in taste. The chlorides & lactose are
mainly responsible for taste.
mainly responsible for taste.
6. Specific gravity:
6. Specific gravity: The specific gravity of milk is
The specific gravity of milk is
determined by using a plunger of special shape &
determined by using a plunger of special shape &
volume called lactometer.
volume called lactometer.
7. Viscosity:
7. Viscosity: The viscosity of milk is always higher
The viscosity of milk is always higher
than viscosity of water due to presence of dissolved
than viscosity of water due to presence of dissolved
solids in milk. At normal temperature viscosity from 1.5–
solids in milk. At normal temperature viscosity from 1.5–
2.
2.
8. Boiling point of milk:
8. Boiling point of milk: The Boiling point of milk
The Boiling point of milk
varies from 100.17 - 101°c. This is slightly higher than
varies from 100.17 - 101°c. This is slightly higher than
that of water due to dissolved substances in milk.
that of water due to dissolved substances in milk.

12. 9. Freezing point of Milk:
9. Freezing point of Milk: Milk freezes at an
Milk freezes at an
average temperature of -0.55°c (range -0.5°c to -0.61°c),
average temperature of -0.55°c (range -0.5°c to -0.61°c),
which is slightly lower than that of pure water (0°c).
which is slightly lower than that of pure water (0°c).
10. Electrical conductivity:
10. Electrical conductivity: Electrical conductivity is
Electrical conductivity is
a measure of the ability of solution to carry electrical
a measure of the ability of solution to carry electrical
current. Value of electrical conductivity for normal milk
current. Value of electrical conductivity for normal milk
range from 0.003-0.005 mhos/min.
range from 0.003-0.005 mhos/min.
11. Thermal conductivity:
11. Thermal conductivity: It is important because it
It is important because it
determines how fast milk is heated or cooled. At 20°c,
determines how fast milk is heated or cooled. At 20°c,
thermal conductivity of milk is 0.50-0.53 W/mK.
thermal conductivity of milk is 0.50-0.53 W/mK.
12. Heat stability of Milk:
12. Heat stability of Milk: It is defined as the length
It is defined as the length
of time required to induced coagulation at a given
of time required to induced coagulation at a given
temperature or temperature required to induce coagulation
temperature or temperature required to induce coagulation
in a given time.
in a given time.

13. Milk
Milk Proce
Processing Operations:
ssing Operations:
Once th milk has been received at the milk
Once th milk has been received at the milk
processing centre, or dairy, it should be
processing centre, or dairy, it should be
immediately strained, cooled & processed so as to
immediately strained, cooled & processed so as to
prevent any bacteriall growth.
prevent any bacteriall growth.

14. MILK PROCESSING
MILK PROCESSING
OPERATIONS
OPERATIONS

15. PASTEURIZATION
Pasteurization is the process and applied to market
milk today. Milk are heating at least 630
C for 30
minutes, or 72°C for 15 second.
After pasteurization ,the milk is immediately cooled to
5°C or below.

16. History of pasteurization
1. Pasteurization term is first time used by
Louis Pasteur in 20 April 1862.and
eliminate bacteria in wines
2. The pasteurization of milk was adopted
in 1895.

17. Method of Pasteurization
1. Low temperature long time (LTLT)
2. High temperature short time (HTST)
3. Ultra high temperature (UHT)

18. 1. LTLT: Low temperature long time
this method commonly know as Batch or Holding
method of pasteurization and ideal temperature is
63C for 30 minute(Milk)
2. HTST: High temperature short time.
This method is know as continuous
process of pasteurization and is 72C for 15
second.
3. UHT: Ultra high temperature. This
process was developed in 1950.and
temperature are provide 135C to 150 C for
one second

19. HOMOGENIZATION
HOMOGENIZATION
Breakdown of milk fat globules is called
Breakdown of milk fat globules is called
Homogenization and fat globules
Homogenization and fat globules
subdivision to 2 microns or less in diameter.
subdivision to 2 microns or less in diameter.

20. Effect of
homogenization on milk
1.
1. Increased the viscosity of Milk.
Increased the viscosity of Milk.
2.
2. Reduced the milk curd tension.
Reduced the milk curd tension.
3.
3. More creamier structure, bland flavor.
More creamier structure, bland flavor.

21. Merits & Demerits of Homogenization
Merits:
1. No formation of cream layer
2. Produces soft curd and better digested
3. More palatable to brighter appearance
Demerits:
1. Increased cost of production
2. Greater tendency for milk
3. Curdling in cookery

22. CREAM SEPRATION
CREAM SEPRATION
The basic principle of cream sepration is
The basic principle of cream sepration is
based on the fact that density of fat (930
based on the fact that density of fat (930
kg/m
kg/m3
3
)
) is lower than milk average 1036
is lower than milk average 1036
kg/m
kg/m3
3
). Hence when mlik which may be
). Hence when mlik which may be
considered to be a mixture of fat (as
considered to be a mixture of fat (as
cream) & skim milk, is subjected to either
cream) & skim milk, is subjected to either
gravity or a centrifugal force the two
gravity or a centrifugal force the two
components, viz. cream & skim milk by
components, viz. cream & skim milk by
virtue of their differing densities, stratify
virtue of their differing densities, stratify
from one another.
from one another.

23. Gravity Seperation Method
Gravity Seperation Method

24. Centrifugal separation method
Centrifugal separation method

25. STANDARDIZATION
STANDARDIZATION
Standrdization refers to the adujestment
Standrdization refers to the adujestment
( i.e. raising or lowerin the fat and/ or solid –
( i.e. raising or lowerin the fat and/ or solid –
not-fat %). Of milk to desired value, So as to
not-fat %). Of milk to desired value, So as to
confirm to some lefgal or others
confirm to some lefgal or others
requirement.
requirement.

26. MIXING OF INSGREDIENTS
MIXING OF INSGREDIENTS
Ice cream contains numbers of ingredients
Ice cream contains numbers of ingredients
obtained from various source. The
obtained from various source. The
ingredients used in the manufacture of ice
ingredients used in the manufacture of ice
cream include dairy (like whole milk, skim
cream include dairy (like whole milk, skim
milk, cream, frozen cream, butter, butter oil
milk, cream, frozen cream, butter, butter oil
condensed milk products,dried milk product,
condensed milk products,dried milk product,
and non dairy product like sugar, stabilizer
and non dairy product like sugar, stabilizer
and emulsifiers.
and emulsifiers.