Milk composition

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M.S. UNIVERISTY
TIRUNELVELI.

2. • It is the secretion of mammary glands in human and animals after
labour.
• It is the only food for newborn for a long period till weaning time.
• Before birth the fetus receives its nutrition through the placenta.
• Milk secretion is stimulated by Prolactin.
• Milk flow is decreased by Estrogen and Progesterone while
increased by Thyroxin.
• Initiation of lactation may result from sudden removal of the
placenta and other factors.
• Oxytocin (posterior pituitary hormone) responsible for milk
ejection.

3. Composition of milk
• Water is the principal constituent of milk.
• Milk provides essential nutrients and is an important sources of dietary energy,
high quality proteins and fats.
• Milk consist of nutrients like calcium,magnesium,selenium,riboflavin,vitamin
B12 and pantothenic acid.
• Milk and milk products are nutrient dense foods and their consumption can
add diversity to plant based diets.
• Animal milk can play an important role in the diets of children in populations
with very low fat intakes and limited access to other animal source foods.
• The colour,flavour and composition of milk depends on the species of dairy
animal, its breed, age and diet, along with the stage of lactation, parity
(number of parturition),farming system, physical environment.

4. Milk composition in dairy animals
Cow milk
Water -87%
Fat – 3-4%
Protein – 3.5%
Lactose - 5%
Minerals -0.8%
Yak milk
Water – 83%
Fat – 5.5 to 9%
Protein – 4 to 5.9%
Solid content – 18%

5. Equine milk( Horse and Donkey milk)
Water – 91%
Fat – 1.9%
Protein – 2.5%(particularly caseins)
Lactose – 6.3% (rich)
Minerals – 0.3%
Camel milk
Water – 86.5%
Fat – 4%
Protein – 3.6%
Lactose – 5%
minerals – 0.4%
Human milk
Water – 87.6%
Fat – 4%
Protein – 1.2%
Lactose – 7%
Minerals – 0.4%

6. Goat milk
Water – 87%
Fat – 4%
Protein – 3.6%
Lactose- 4.5%
Minerals – 0.9%
Sheep milk
Water – 80%
Fat – 8%
Protein – 5.6%
Lactose – 4.8%
Minerals - 0.9%
Buffalo milk
water – 82%
minerals – 0.8%
protein – 4.5%
lactose – 4.8%
fat – 7 to9%
very high fat content

7. Milk is formed of
1) Water: form 87%.
2) Solids: form 13%.
 Organic constituents of
milk. 1.Protein
2.Lipid.
3.Carbohydrate.
 Inorganic constituents of milk:
1. Minerals.
2. Vitamins.

8. 1- Protein:
• Milk protein less in human than in cow's milk.
• All milk protein synthesized in the mammary gland.
• Milk protein of high coefficient digestibility (85 – 95%)
Characterized by:
1. Protein of high biological value as:
• It contains all essential amino acids.
• Easily digested.
• Easily absorbed.
• Easily metabolized.
2.It Contain moderate amount of non essential amino acids to decrease stress on
body cells.
3.Essential to keep positive nitrogen balance (nitrogen intake more than nitrogen
output).
4.Essential to maintain growth of newborn.

9. Types of Milk Proteins are:
1.Casein.
2.Lactalbumin.
3.Lactglobulin.
4.Milk enzymes.
1) Casein
• It is the main and most dominant milk protein.
• It represents 25% in human's milk and 83% in cow's milk.
• It is a compound protein (Phospho-protein) of high biological
value.
• The high phosphate content of casein allows it to associate with
calcium and form calcium phosphate salts.
• Casein contains
0.7% phosphorous and 0.7% sulpher.
• Casein is the only milk protein that not coagulated on boiling.
• The net charge of milk protein is negative charge, so protein
molecules remain separated from each others due to repulsion
forces.

10. 2. Lactalbumin
• Represent 87% of whey protein.
• Protein precipitation by full saturation with
ammonium sulphate.
• Rich in cystein and cystin so give +ve result
with sulpher test.
• Simple protein.
• Soluble protein.
• Easily digested.

11. 3- Lactglobulin
• Represent 13% of whey protein.
• Protein precipitation by half saturation with
ammonium sulphate solution.
• Rich in cystein and cystin so give +ve result with
sulpher test.
• Simple protein.
• Soluble protein.
• Easily digested.
• Consists of two fractions:
α Lactalbumin
β lactglobulin
32% of whey protein.
55% of whey protein.

12. 4- Milk enzymes:
1. Catalase.
2. Peroxidase.
3. Xanthin oxidase.
4. Alkaline phosphatase.
5. Amylase.
6. Lipase.
7. Aldehyde oxidase.

13. •
•
•
•
• Human's and cow's milk contain the same amount 3.5 gm/dl but
buffalo's milk is a little higher 7 gm/dl.
Easily separated on standing.
Responsible for white color of milk
It consists mainly of triacylglycerol distributed as coarse emulsion
which contains oleic, myristic, palmitic and stearic fatty acids.
Also contain small amounts of:
phospholipids 0.1%
Cholesterol 0.01%.
• Lactose (milk sugar) is the only carbohydrate of milk.
• It is a reducing disaccharide consists of glucose and galactose.
• Human's milk contains 7% lactose while cow's milk contains 5% lactose.
• Lactose may be excreted in urine during last third of pregnancy
physiologically so it should be differentiated from glucose by osazon test.

14. 1- Minerals:
•
• Human milk contain less mineral elements (0.4%) than cow's milk (0.8%).
• Milk rich in Ca and P which are present in their proper ratio for absorption
(2:1) in human milk while in cow's milk (1:2)
Ca and P are essential for:
1. Growth of bone and teeth.
2. Stability of casein.
Milk contain adequate amount of Na, K, Mg.
Human milk contains Na:K (1:2) which is suitable for the optimal growth
of newborn.

15. 2- Vitamins:
• Milk is deficient in:
• Vitamin C. ( form – Ascorbic acid 1.5mg in 100ml cow milk)
• Vitamin D.
• Vitamin K.
• Milk contain adequate amount of vitamin B complex which are sufficient
for first week of life
e.g:
Pantothenic acid.
Riboflavin (gives the whey the greenish tint in sunlight)

16. milks 9 essential nutrients
1. Calcium = strong bones
2. Vitamin D = calcium absorption
3. Riboflavin = energy
4. Phosphorus = strong bones
5. Protein = lean muscle
6. Potassium = fluid balance & blood pressure
7. Vitamin A = good vision & skin health
8. Vitamin B12 = red blood cell formation
9. Niacin = energy

17. 1. Species:
► Milk protein:
Rabbit's milk 10% while cow' milk 3.7%.
► Milk fat:
Cow's milk 3.5% while buffaloe's milk 7%.
2. Age:
► Old age decrease fat contents of milk.
3. Seasonal variation:
► In winter increase in fat, protein and mineral contents of milk.
4. Nutritional variation:
► Overfeeding has no effect on milk composition.
► Underfeeding decrease in milk volume and protein and lactose
contents of milk while fat contents of milk increased.
5. Infection of mammary gland:
► Mastitis decrease fat, lactose and casein contents of milk while
whey protein and chloride ions increased.

18. • Cultured Dairy Products - yoghurt
• Butter
• Cream
• Cheese
• Concentrated Dairy Products
• Frozen Dairy Products

19. Dietetic Value
⦿Yoghurt contains HBV protein
necessary for growth, therefore it is a
suitable food for children &
teenagers and necessary to repair
cells, essential for those recovering
from illness
⦿Yoghurt is easily digested & is
suitable for the elderly &
convalescents
⦿Low-fat yoghurts are available & are
particularly suitable for those on
low-kilocalorie diets
Economic Value
⦿Yoghurt can be
used in a wide
variety of dishes
⦿ Yoghurt is available
in a wide variety of
flavours
⦿ Yoghurt is relatively
inexpensive to buy

20. Nutritive Value
Nutrient Explanation
Protein •HBV
Fat • Saturated fat
•Amount depends on the type of milk : low
fat, skimmed or full-fat
Carbohydrate • Milk sugar lactose
• Can be introduced by the addition of
fruit & sweeteners
Vitamins •Fat – soluble: A & D
•Water – soluble: B1 thiamine, B2
riboflavin and niacin
Minerals • Calcium
•Small amounts of potassium & phosphorus
Water • Varies according to the fat content

21. Storing yoghurt
⦿ Store in a refrigerator (below 5˚C)
⦿ Use within the best before date
Bio-yoghurts contain additional bacteria cultures such as
lactobacillus casei, which manufacturers claim support the
natural bacteria in the intestines & help to regulate digestion

22. • Manufactured from milk .A water-in-oil emulsion
Nutrient Explanation
Protein •A little High Biological Value protein in
butter
Fat • Animal fat (saturated fat)
• The fatty acid is called butyric acid
Carbohydrates • Trace amounts of lactose(milk sugar)
Vitamins • Fat-soluble vitamins A, D & E
Minerals •Traces of calcium & phosphorus
• Sodium & chloride are added during
production
Water • Small amount - 14-16%

23. Composition of Butter
Protein Fat Carbohydra
te
Vitamins Minerals Water
1% 82% 0.5% 0.5% 2% 14%
⦿ Must contain at least 80% fat to be called
butter, by law.
Production of Butter
1. Cream(fat from milk) is pasteurised
2. Cream is cooled & the fat hardens
3. Cream is churned & the fat clumps together
4. The liquid part, called buttermilk, is drained off
5. Salt (1.5 %) is added
6. The butter is packed for sale

24. Types of Butter
Type Use
1. Salted: 2% salt is added Baking, table use
2. Unsalted: No salt added Low sodium diets, baking
3. Spreadable Butter: Churned for longer
periods of time to allow for the fat globules to
separate. This allows for a more spreadable
product
Sandwiches
4. Low-fat: Fat content reduced by 50% Low kilocalorie diets
5. Concentrated Butter:
made up of 84% fat
Sandwiches

25. • Milk is an oil-in-water emulsion.
• Cream is made from the fat of milk
Nutrient Explanation
Protein • Approx. 3% in cream
• HBV (animal protein) called casein
Fat • Varying quantities ofsaturated fat
• Depends on the type of cream
Carbohydrate • 2-4% called sugar lactose
Vitamins • Small amounts of B group vitamins
• A & D
Minerals • Calcium
Water • Varies according to type

26. Production of cream
1. Milk is heated to 50°C
2. It is then subjected to centrifugal force which
separates the upper cream layer from the lower
layer of skimmed milk
3. The cream is heated using pasteurisation,
sterilisation or ultra-heat treatment

27. Types of Cream
Type of cream Use
Half Cream 12% fat • Pouring cream used in desserts
Single Cream 18% fat • Pouring cream used in desserts & sauces
Double Cream 48% fat
• Decoration of desserts
Whipping Cream 35% fat
• Decoration of desserts
UHT Cream 35% fat
• Trifles
Sour Cream 18% fat • In savoury dishes, e.g. sweet & sour
Cream Alternatives:
a) Crème Fraiche 30% fat
• A mixture of soured cream & yoghurt or buttermilk
b) Fromage frais 13% fat • Blend of soft cheeses
c) Greek Yoghurt 10% fat •Thick creamy yoghurt used instead of cream.

28. Classification
Hard cheese Semi-hard
cheese
Soft cheese Processed
cheese
•Cheddar
•Parmesan
•Swiss
•Stilton
•Gouda
•Cottage
•Brie
•Mozzarella
•Feta
•Cheese
spread
•Cheese slices
•Smoked
cheese
Type Protei
n
Fat Carb. Vitamins Mineral
s
Water
•Hard
•Soft
26%
14%
33%
4%
0%
4%
A, B2
A, B2
Calcium
Calcium
37%
77%
Composition of Cheese

29. Nutritive Value
Nutrient Explanation
Protein • HBV caseinogen
Fat • Saturated
• Hard cheese has more than soft cheese
Carb. •None in hard cheese, as they are lost during
processing
•Small proportion in soft cheese of the
disaccharide lactose present
Vitamins • Vitamin A, B2(riboflavin) & D
• No vitamin C
Minerals •Hard cheese is a very good source of calcium
Water •Hard cheese 33%
•Soft cheese 75%

30. Cheese-Making
1. Milk is pasteurised
2. Lactic acid bacteria is added .This changes lactose(milk
sugar) to lactic acid
3. Milk is warmed to approximately 30°C
4. The enzyme rennet is added - milk protein, caseinogen
converts to casein.
The mixture is left for between 30-45 mins until casein
turns to curds(solid) & whey(liquid)
5. Whey is drained off & the curds are chopped
= Cottage cheese
6.Scalding =the curds are heated again (to 40°C) to shrink
them further & the squeeze out more whey.
7.Cheddaring=the curds are cut into blocks & packed on
top of each other to remove any remaining whey.

31. 8. 2% salt is added & more whey is drained off
9. The cheese is pressed into moulds
10.For protection, the cheese is sprayed with hot water &
this forms a rind
11.The cheese is removed from moulds & wrapped in
polythene bags, where it is left to ripen.
Ripening time varies with the type of cheese, e.g. cheddar
cheese is left to ripen for up to one year at 10°C.
Cheddar cheese is produced at this point
12. The cheese is date-stamped, graded & packed

32. Dietetic Value of cheese
children, adolescents,
pregnant women & nursing
mothers
for active people
⦿ Cottage cheese (4% fat)
and low-fat types for low-
kilocalorie/low cholesterol/
weight-watching diets
⦿Lacks carbohydrates,
should be eaten with foods
rich in carbohydrate e.g.
brown bread
Dietetic Value of cheese Economic Value
⦿ Rich in protein & calcium - ⦿Versatile, used in a wide
essential for growth in range of dishes
⦿ Economical - little or no
waste
⦿ Quick & convenient
⦿High-energy food - suitable ⦿ High energy, nutritious
snack

33. • Hot snack – cheese on toast
• Cold snack - sandwich
• Sauce making – cheese sauce
• Fillings - omelettes
• As dips & spreads
• Toppings - pizza
• Course at end of meal – cheese board
• Protein alternative
• Enhances nutritive value of a dish
Culinary uses of cheese

34. • Dairy products that have been prepared and
stored at very low temperatures
– ICE CREAM
» Made from milk, cream, sugar and flavoring
» Generally has about 6-8 grams of fat
» REDUCED FAT has about 4-5 grams of fat
» LOWFAT has less than 3 grams of fat
» NONFAT has less than 0.5 grams of fat
– SHERBERT
» Made from milk, sugar and fruit juice
– FROZEN YOGURT
» Made from cultured dairy product, sugar &
flavoring

35. • Dairy products that have had the water or liquids removed
to increase the density
• Examples include:
– EVAPORATED MILK
» Has some water removed
» Can be reconstituted and used as fresh milk
» Available in cans
– SWEETENED CONDENSED MILK
» Has water removed and sweetener added
» Used most commonly in baking
» Cannot replace fresh milk or evaporated milk
» Available in cans
– NONFAT DRY MILK POWER
» Used by chefs because it does not spoil and it costs less
than fresh milk
» Can be reconstituted and used as fresh milk
» Comes powdered in packets (boxes)… think hot cocoa