TECHNOLOGY OF MILK AND MILK PRODUCTS

Definition of milk:

A white or yellowish liquid consisting of small fat globules suspended in a water solution, secreted by the mammary gland for the nutrition of the newborn.

Milk components (>100000 molecular components)
 Water
 Carbohydrate
 Fat
 Protein
 Minerals & Vitamins
Total solids:
Fat+protein+carbohydrate+Min. & Vit.+ enzymes
SNF:
protein+carbohydrate+Min. & Vit.+ enzymes
Skim milk (Plasma):
Milk-fat
Whey (Serum):
Skim milk-casein micelles

Milk Fat:
 The most variable milk component in both concentration and composition.
 Excellent source of energy (2.25>protein & CHO)
 Adipose tissue (subcutaneous fat) protects the young in cold environment.
Physical Structure of Milk fat:
Size of fat globules :
 0.1-15 µm in diameter
 covered by thin membrane
Thin membrane:
 Origin: apical membrane of the secretary cell
 Composition: Protein & Phosphate
Chemical Composition of Milk:
 Triglyceride or triacylglycerol (>95%)
 Phospholipids
 Diacylglycerol
 Cholesterol
 Unesterified fatty acids

Milk fat contain >400 fatty acids
• Fatty acids: Hydrocarbon chain and carboxyl group
• Triglycerides: glycerol+ three fatty acids

Milk Fatty acids
 Saturated fatty acids: No double bond.
 Unsaturated fatty acids: One or more double bond.
 Poly-unsaturated fatty acids: Two or more double bonds
Fatty acid composition of milk fat varies considerably among mammalian species( unlike milk fat components)
Source of variation:
1. chain lenghth (short-, medium- or long-chain FA)
2. Degree of unsaturation
3. Position of fatty acids on the glycerol skeleton.

General observations about milk fat:
 Fatty acids composition of milk is influenced by the diet of the lactating female mire than any other milk component.
 Milk contains higher proportion of short- & medium- chain fatty acids than the other body tissues.
 Milk of ruminant species contain higher levels of shirt –chain fatty acids(Milk fat related to beef & Pork fat:
Shot-chain fatty acids

C18 fatty acids

Polyunsaturated fatty acids

Milk fatty acids:
• Long chain fatty acids; C16-C18
• Medium chain acids, C10-C14
• Short chain fatty acids: C8-C4
• Palmitic (C16:0) and oleic (C18:1) acids are the most abundant fatty acids in milk of most of most mammals (Elephant & rabbit are exception)
• Oleic acids(C18:1) is most abundant unsaturated fatty acids of milk acid in milk of most mammals milks of whales & seals contain high level of long chain poly unsaturated fatty acids(>C18:3)

The real view:
 Beef contain lipoproteim (aldehryde substance)
 Vegetable fat contain less amount of essential fatty acids
 Milk rich in essential fatty acids which prevents fat deposion in the Body.
Cholesterol:
• A waxy, fat-like substance present in every cell in the body and in many foods
• Cholesterol also comes from eating foods taken from animals such as egg yolks, meat, and whole-milk dairy products.
• Cholesterol is important for good health and is needed for making cell walls, tissues, hormones
• The dietary recommendation of cholesterol intake is 200-400 milligrams per day
• However, as the body makes its own cholesterol, dietary cholesterol is not an essential nutrient.
Cholesterol foods:
• High cholesterol: Organ meats,
• Moderate cholesterol: Meats, milk products with medium to high fat content.
• Low cholesterol: Milk products with low fat content.
• Very low cholesterol: Skim milk products.
• No cholesterol: Plant foods.