By-products of the dairy industry and their utilization

1. UTILIZATION OF
BY-PRODUCTS OF DAIRY
SUBMITTED TO SUBMITTED BY
Dr. Barinderjit Singh Sakshi Thakur
M.Sc. Food Science and Technology
IKG Punjab Technical University

2. INTRODUCTION
• By-product is a secondary product derived
from manufacturing process or chemical
reaction.
• It may not sound as important as main
product manufactured.
• In Dairy industry, by-products manufactured
from milk are skimmed milk, casein,
caseinate, whey, whey powder, whey
protein concentrate, buttermilk and ghee
residue.

3. Contd....
• Some of the by-product like skimmed milk,
buttermilk and whey if not properly utilized
may create acute problem of environmental
pollution.
• But if these are utilized properly they
contribute to the profit.

4. QUANTITY OF PRINCIPLE BY-
PRODUCTS
• For every pound of butter made there are
15-20 pounds of skim milk and about 3 pounds
of butter milk, and for every pound of cheese
nearly 9 pounds of whey.
• The aggregate of these by-products are
therefore enormous.

5. MANAGEMENT CHALLENGES
• The 4 F pyramid represent the historic value
hierarchy of dairy byproducts. Following
human consumption, the highest potential
market value has been for supplemental animal
feed application, followed by fuel and
fertilizer.

6. MAIN PRODUCT BY-PRODUCT PROCESSING
METHOD
PRODUCTS MADE
CREAM SKIM MILK
PASTEURIZATION,
STERILIZATION,
FERMENTATION
FLAVOURED MILK,
CULTURED BUTTER
MILK, COTTAGE
CHEESE
BUTTER BUTTER MILK
COAGULATION,
FERMENTATION
AND
CONCENTRATION
CONDENSED
BUTTERMILK, SOFT
CHEESE, DRIED
BUTTER MILK
CHEESE,CHANNA
CASEIN, PANEER WHEY
FERMENTATION,
COAGULATION,
CONCENTRATION,
DRYING
WHEY BEVERAGE,
YEAST WHEY,
DRIED WHEY,
WHEY PASTE
GHEE GHEE RESIDUE PROCESSING
SWEET MEAT,
TOFFEE, SWEET
PASTE

7. SKIM MILK
• Skimmed milk should be considered first as it is of
the greatest in quantity of the by-products of
dairying.
• Skim milk is that portion of whole milk which remains
after the removal of the cream.
• This process is called skimming.
• It is rich in solid-not-fat content and has high
nutritional value.
• It may be utilized for manufacturing of main dairy
products or preserved by removing moisture in spray
dried form to obtain skim milk powder.
• When skim milk is consumed in any of these two
products then it is not considered as by-product.

8. Contd...
• It is considered as by-product when it is either not
economically utilized or utilized for derived product
like casein, co-precipitate, protein hydrolysate etc.
• Casein is the major protein in milk and constitute 80%
of total protein content and about 20% is whey or
serum protein.
• Casein is commercially made from skim milk by
o Precipitation by acid to make acid casein
o Coagulation with rennet to make rennet casein
• In addition to these there are other commercial
casein product
o Coprecipitate
o Caseinates

9. • According To PFA, fat from the skimmed milk has
been removed mechanically and shall not contain more
than 0.5% milk fat and not less than 8.5% milk solid-
not fat.
REQUIREMENT
FOR EDIBLE
CASEIN
INTERNATIONAL STANDARD
EXTRA GRADE STANDARD GRADE
BIS STANDARD
MOISTURE,% BY
Wt.
12 12 10
COPPER, max. - - 2.5
FAT, % BY Wt. 1.7 2.25 1.5
PROTEIN, % BY
Wt.
95 90 -
LACTOSE, % BY
Wt.
0.2 0.1 -
BACTERIAL
COUNT, Per gm
30,000 100,000 50,000

11. ACID CASEIN
• In the market two types of casein are available:
Edible casein and Industrial casein (non-edible).
• These two casein can be either acid casein or rennet
casein.
• Edible casein is used as an ingredient in many dairy
and food product.
• It has different manufacturing process than non-
edible casein.
• It is produced under sanitary conditions.
• During its manufacturing, food grade chemicals are
used and sufficiently heat treated to make it safe
for human consumption.

12. MANUFACTURING PROCESS
• RAW MATERIAL AND ITS INFLUENCE
• PRECIPITATION
• TEMPERATURE OF PRECIPITATION
• DRAINING OF WHEY
• WASHING (pH of wash water and Temperature of
wash water)
• PRESSING
• MILLING AND DRYING
• GRINDING, STIFFING AND BAGGING

13. RENNET CASEIN
• Skim milk, normally pasteurized at 72⁰C for 15-20⁰C is
used for the production of rennet casein.
• The milk is then cooled at 30⁰C .
• Sufficient rennet and calcium chloride is added to the skim
milk to give a setting time of 20-30 minute.
• A gel forms which is then cut and the coagulum is stirred
while being heated to about 60⁰C .
• The high temperature is necessary to deactivate the
enzyme.
• Cooking time is approximately 30 minute washing and
remaining steps are the same as that of casein.
• Here the wash water is neutral.

14. CASEINATE
• It is the chemical compound of casein and light
metals, for instance monovalent sodium or divalent
calcium.
• It is produced from freshly precipitated wet (acid)
casein curd or from dry acid casein by reaction with
any of the several diluted solution of alkali i.e. Sodium
hydroxide, potassium hydroxide, calcium hydroxide or
ammonium.
• Different types of caseinate are
 Sodium caseinate
 Calcium caseinate
 Other caseinate like magnesium caseinate

15. COMPOSITION OF CASEINATE
SODIUM CASEINATE CALCIUM CASEINATE
MOISTURE 3.8 3.8
PROTEIN 91.4 91.2
ASH 3.6 3.8
LACTOSE 0.1 0.1
FAT 1.1 1.1
CALCIUM 0.1 1.3-1.6
COPPER 1-2 1-2

16. THE BEST USE OF SKIM MILK
• The best use to which skim milk can be
applied is as human food, in its uncooked
state.
• The use of skim milk instead of whole milk as
food, in its natural state, is simple a matter
of taste and habit.
• A quart of skim milk contains more proteins
than the whole milk and the former is cheaper
and better than the latter as a substitute for
meats and other animal foods.

17. Contd...
• A report upon dietary studies made at
University of Tennessee in 1987 said that the
nutrients in milk are equal in physiological
value to those of meats , and are far less
expensive.

18. SKIM MILK AS COOKING
• Beside the use of skim milk as human food in
its raw state, there are many ways in which it
can be advantageously used in cooking.
• As a substitute for water in preparing various
dishes, as well as for others mainly made of
milk, there is no waste and a gain in food
value.
• This is especially true for making bread.
• Milk adds weight and nutritive value of the
loaf.

19. Contd...
• Substituted for water, enough flour may be
saved to more than pay for the milk, and yet
produce a loaf of equal weight and greater
food value.
• Comparison of skim-milk and water bread
KIND OF
BREAD
WATER
(%)
FAT (%) PROTEIN
(%)
CARB.(%)
WATER
BREAD
39.95 0.12 7.31 52.92
SKIM
MILK
BREAD
38.61 0.51 9.19 51.38

20. • It is more clear from the comparison that
skim-milk bread is more nutritious than the
ordinary water bread.
• In white bread, the use of milk instead of
water, gives a loaf an excellent appearance
and taste, and the milk not only renders it
more valuable as food, but easier for
digestion.
• Bakers have long known the value of skim milk
in bread making, and they give the reasons for
using skim milk instead of water:
 It makes loaf moist and will remain moist longer
 It makes a closer loaf

21. Contd...
It improves the eating quality of bread
The sugar in milk caramel in baking and
browns the crust

22. SKIM MILK AS FEED FOR DOMESTIC
ANIMAL
• Next to human food, the most profitable use
to which skim milk can be applied is in feeding
domestic animals of various kinds.
• Some important facts which proved skim milk
good feed for animals are :
Skim milk gives the best return when fed to very
young animals, constituting the greater part of
their food.
It next best for animals making rapid growth but
which need food other than milk and mainly of a
more carbonaceous character

23. Contd...
Except for the very young, skim milk gives much
better results when used in combination with other
materials, generally grains, than when fed alone.
No class of live stock gives a better return for
skim milk fed to it than poultry of various kinds.
• The nutritive ration of skim milk ranges from
1:1.7 and 1:2, therefore it is highly
nitrogenous food and too concentrated to be
use alone.
• So it should be used with some carbonaceous
material, like corn meal etc.

24. CHEESE MADE OF SKIM MILK
• Skim milk may be made into cheese.
• Skim cheese has a really high food value, and
may be used to advantage in cooking.
• In Europe both hard and soft cheeses, and
several varieties of these, are made from the
skim milk.
• The skim milk conversion into cheese of
better quality deserves more attention in
America.
• Skim cheese should always enter the market,
plainly marked and fully identified, as is
required by law in several states.

25. • COTTAGE CHEESE
This product, also called pot cheese or smear
case, is a form into which skim milk is easily
converted. It is nutritious and a favorite not
only at home but also in markets of cities and
towns.
• FILLED CHEESE
In Europe it is known as ‘Margarine cheese’.
To the skim milk is added some cheap form of
fat, usually of animal origin, but sometimes
vegetable, to replace the original fat of milk.

26. FERTILIZER FROM SKIM MILK
• Skim milk can be used, either in its natural
state or in manufactured state, as food for
man and animal.
• Skim milk possesses a positive value as a
fertilizer.
• Skim milk has not higher value as manure, if
directly applied to growing crops.

27. CASEIN FROM SKIM MILK AND
ITS USES
• There are many other ways to use skim
milk, beside its use as food for animal
and plants.
• The casein and the sugar in the skim
milk, which are its principle solid
constituents, can both be separated and
put into a commercial form.
• Casein when separated and dried, forms
a hard, elastic mass, which can be used i
different ways.

28. • Casein when combined with the oxides and
salts of the metals of calcium group, casein
forms a cement-like compound, insoluble in
water.
• Paper dressed with casein
• Use of whey from casein as hog feed
• Fertilizer from casein
• Casein as a substitute for celluloid

29. SKIM MILK IN WHITEWASH AND
IN MANUFACTURES
• The use of skim milk in whitewash has been
known toprevent the coating from peeling off,
and one time the Department of Agriculture
gave out a simple recipe for makin skim milk
paint.
• It is mixed with hydraulic cement, or water
lime, so as to make a thin paint, and laid on
with a broad, flat brush.
• One pound of cement to a gallon of milk is the
usual mixture, andshould not be stirred much,
because more stirring can cause hardness.

30. • This makes an excellent, durable, and
inexpensive covering for any structure of
wood or stone.
• If nothing but cement and milk are used, the
color will be light, yellowish brown, but other
colouring material can be added in form of
dry pigment.
• Emulsion of olive oil and skim milk are used in
wool manufacture as a dressing for the wool.

31. BUTTERMILK
• Buttermilk and ghee residues are important
nutritional by-products of butter and ghee making
industry.
• Buttermilk is an important by-product obtained
during the manufacturing of butter.
• Normally, in our country three types of buttermilk
are produced:
 Sweet cream buttermilk
 Sour buttermilk
 Desi (lassi) buttermilk
• The sweet and sour buttermilks are produced in
organised sector and lassi at household levels in small
quantities.

32. GROSS COMPOSITION OF BUTTERMILK
AND SKIM MILK
CHARACTERISTIC SKIM MILK SWEET CREAM
BUTTERMILK
T.S 10.38 9.88
FAT 0.09 0.59
TOTAL PROTEIN 4.27 3.73
LACTOSE 5.2 4.81
ASH 0.82 0.75
TITRABLE ACIDITY 0.16 0.12
pH 6.69 6.86

33. CHEMICAL COMPOSITION OF TYPES
OF BUTTERMILK
• Sour buttermilk differs from sweet cream
milk in respect to titrable acidity.
• The acidity in sweet cream buttermilk
varies from 0.10-0.14%, whereas in sour
buttermilk it is even high as 1%.
• Desi buttermilk has wide range of
composition depending on quality of milk
used for making curd and levels of addition
of water during churning.
• Desi buttermilk contains 4% total solid
consist 0.8% fat, 1.29% protein, 1.2% lactic
acidity.

34. PROCESSING AND DRYING OF SWEET
CREAM BUTTERMILK
CHARACTERISTICS SKIM MILK POWDER SWEET CREAM
BUTTERMILK
POWDER
MOISTURE (%) 2.75 2.59
FAT (%) 1.05 6.38
TOTAL PROTEIN 40.29 37.09
LACTOSE 48.15 47.00
TITRABLE ACIDITY 1.39 1.17
SOLUBILITY INDEX 0.30 0.15
BULK DENSITY 0.544 0.345

35. UTILIZATION OF SWEET
CREAM BUTTERMILK
• Sweet cream buttermilk can be used in beverage form
and in fluid milk industry as a milk extender.
• Buttermilk is also used to manufacture soft varieties
of cheese, paneer, fermented milks and traditional
milk products.
• Physico-chemical properties of buttermilk and skim
milk is different due to which provide selective
application in dairy products manufacture.
• Use of buttermilk are:
BEVERAGE: Butter milk is consumed in plain and
spiced form throughout the year and used as
refreshing drink in summers.

36. MARKET MILK: Sweet cream buttermilk
produced in in organised dairies is partly admixed
with whole milk for fluid milk supply. It has been
observed that use of sweet cream buttermilk in
market milk for toning of buffalo milk improves
the palatability, viscosity, and heat-stability.
FERMENTED MILK PRODUCT: Curd is prepared
by incorporating sweet cream buttermilk into
whole milk has soft body which is probably due to
change in electric charge on casein during
churning, the presence of phospholipid and free
fat in buttermilk.
PANEER : Good quality of paneer can be prepared
by from low fat milk by incorporating buttermilk
solids to buffalo milk.

37. CHEESE: The replacement of skim milk
with sweet cream buttermilk results into
softer body due to the presence of higher
amount of fat globule membrane materials
in buttermilk.
Other material: Sweet cream buttermilk
can also be used to manufacture products
like: khoa, kheer, rubri. Buttermilk can
replace the skim milk powder in
manufacture of gulabjamun mix powder.
Utilization of desi and sour cream
buttermilk

38. GHEE RESIDUE
• Ghee residues are the by-products of ghee
manufacturing industry and is produced in large
quantities in India.

39. • Ghee residue is moist brownish sediment.
• Chemical composition of ghee residues:
SOURCE
OF GHEE
RESIDUE
AVERAGE
% FAT OF
SOURCE
CHEMICAL COMPOSITION
MOISTURE FAT PROTEIN LACTOSE ASH
YIELD
FROM
BUFFALO
MILK
DESI
BUTTER
77.0 13.4 33.4 32.8 15.4 5.2 1.6
CREAMERY
BUTTER
85.0 5.7 65.0 25.5 TRACE 3.8 1.2
SWEET
CREAM
67.0 4.1 63.2 18.0 12.3 2.4 7.7
SOUR
CREAM
67.0 8.0 38.8 41.6 7.3 4.3 5.1
WASHED
SWEET
CREAM
71.0 1.7 80.8 16.2 TRACE 1.3 3.5

40. • Nutritional property: Ghee residue is rich in protein
and fat apart from containing considerable amount of
mineral and can be used as human dietery supplement.
• Antioxidant property: Ghee residue is rich in natural
antioxidant and its antioxidant properties are due to
its constituents affected by various technology
parameters. Its antioxidant properties are due to
lipid and non-lipid constituents.
• Flavouring properties: Ghee residues are also rich
and natural source of flavour compounds like FFA,
carbonyls, lactones.
FFA(µm/g) CARBONYLS(µm/g) LACTONES (µm/g)
GR GHEE GR GHEE GR GHEE
627.5 53.6 43.7 4.3 3992.0 30.3

41. UTILIZATION OF GHEE RESIDUES
• Ghee residues can be utilized in number of products
like chocolate burfi, samosa filling, chapatis etc.
• Most dairy plants in India have not been utilizing GR
except for fat extraction.
• Most of the ghee residues goes to the waste.
• In dairy plants, attempt has been made to recover as
much ghee as possible from ghee residues. Two
recovery methods are there: Pressure technique and
Centrifugal process
• Physico- chemical properties of processed ghee
residues are suitable for preparation of confections.
Preparation of candy

42. Preparation of chocolate:
Preparation of edible paste:
Preparation of burfi type sweet:
Preparation of bakery product:

43. WHEY PROTEIN
• Whey is the another by-product of dairying .
• When cheese is made from milk, whether the milk
be skimmed or not, the only waste product is
whey.
• Whey result from separating the casein from
skim milk.
• From every hundred pounds of milk is converted
into cheese about 90 pounds of whey is obtained.
• Whey is a watery, highly perishable,
semitransparent liquid in appearance, composed
of about 93% of water and 7% of solid (albumin,
sugar, ash, casein, fat)

44. COMPOSITION OF DIFFERENT WHEY
SYSTEM

45. UTILIZATION OF WHEY
• Modern industrial processing technique such as
ultrafilteration , reverse osmosis, new drying
methods, hydrolysis, electrodialysis, ion-exchange,
fermentation etc have converted whey into major
source of ingredient with different functional and
nutritional properties.
• Presence of lactose, protein, minerals and water
soluble vitamins make the whey highly nutritious
product.
• Being a rich source of lactose, whey is good
fermentation media for number of fermented
product.

46. • In many applications, lactose in whole or
deproteinised whey is hydrolysed to glucose and
galactose, thereby increasing its sweetness, such
lactose syrups are used sweet confectionery product
and ice cream.
• Whey cheeses like Mysost, Gjetost are produced in
Norway. The names of whey cheeses in Greece
indicate their quality. Ricotta cheese is popular in
Italy and in many other countries.

47. • A small percentage of whey is demineralised to
produce dry demineralised whey for specialized uses,
these include whey protein based infant formulas and
other medical and nutritional product that require
lactose, special nutritional quality of whey protein and
low mineral content.
• Demineralised sweet whey is also used in coffee
whitener, milk shakes, citrus drinks, animal feed,
confectionary, bakery goods, whey drinks, salad
dressings.

48. VALUE OF WHEY AS FEED FOR
HOGS
• Numerous records shows whey has
considerable value as food for swine, when
mixed with other material.
• Several trials at home indicates that whey
has same feeding value for hogs as half the
same weight of skim milk.
• A number of comparative trials have shown
that sweet whey to be more valuable than
sour whey for feeding.

49. WHEY FOR CALVES AND COWS
• Some foreign trials with calves shows whey to
have about half the value of skim milk, which
is rather more than the general estimate.
• Sweet whey has also been fed to milch cows,
in foreign experiments and satisfactory
results obtained where 10-20 pounds were
given to each animal, in addition to other food.

50. WHEY FOR INVALIDS
• Ordinary whey is considerably used for
invalids, especially in case of lungs and
chlorotic diseases, mainly as an aid to
digestion.
• An article known as “wheyn” has been
patented, which is a purified and sterilized
whey, free from albumen and fat, and
constitutes a nourishing and mildly stimulating
beverages.

51. DAIRY BY-PRODUCT AS FUEL
• High strength dairy by-products contain
significant concentrations of organic
compounds that can potentially be converted
to energy
• In the past, there have been few
commercially viable options for converting
these wastes to fuels