Dairy Products
Milk and Cheese
Milk
• Products of milk (dairy products)
1. Butter
2. Cream
3. Cheese
Milk• Types of milk1. Untreated2. Pasteurised3. Homogenized4. Sterilized5. Ultra-high temperature (UHT)6. Evaporated7. Condensed8. Powdered9. Skimmed
Milk
• Types of milk1. Untreated milk: - has not gone through any kind of heat
treatment- bottled on the farm
2. Pasteurized milk:- given mild heat treatment (72’C for 15
seconds) to destroy most disease-carrying germs
Milk
• Types of milk
3. Homogenised milk: pasteurised milk processed to disperse the fat globules and distribute them evenly throughout the milk
4. Sterilised milk: homogenised milk heated to a high temperature (113’C) for 15 – 40 minutes
Milk• Types of milk5. Ultra-high temperature
(UHT) milk: homogenised milk heated to a high temperature of 132’C for not more than one second
- can be kept for months without refrigeration
Milk• Types of milk6. Evaporated milk: some water has been
removed from the milk through evaporation
- contains 25% less water than fresh milk - sterilised at 115.5’C for 20 minutes7. Condensed milk: some water has been
removed from milk through evaporation - sweetened with sugar
Milk
• Types of milk
8. Powdered milk: all water has been removed (powder form)
9. Skimmed milk: fats have been skimmed off the milk
Nutritive Value of Milk
1. Proteins- High biological value- Caseinogen (80%), lactalbumin, lactoglobulin
2. Fats- In the form of very tiny droplets dispersed
throughout the milk (emulsion)- Milk fats are used in the production of cream
and butter
Nutritive Value of Milk3. Carbohydrate- In the form of lactose (milk sugar)
4. Vitamins- A, D, B1, B2
5. Minerals- Calcium- Phosphorus- Sodium- Chlorine- Potassium
6. Water: 87%
Effect of Heat on Milk• When milk is boiled, proteins coagulate
and form a layer on the surface.
• As boiling continues, hot air and steam get trapped under this layer.
• This results in milk overflowing from its container.
Cheese
• A concentrated form of milk
• It is a means of preserving nutritive value of milk
Types of Cheese
1.1. Very hard cheese: water content is 30 – 32% Very hard cheese: water content is 30 – 32% (Parmesan cheese: grated for sprinkling on (Parmesan cheese: grated for sprinkling on cooked food)cooked food)
2.2. Hard cheese: water content is 37 – 40% Hard cheese: water content is 37 – 40% (Cheddar cheese: grated for use in cooking)(Cheddar cheese: grated for use in cooking)
3.3. Soft cheese: water content is 50% (Cream Soft cheese: water content is 50% (Cream cheese, processed cheese and cottage cheese, processed cheese and cottage cheese: used as spreads on biscuits and for cheese: used as spreads on biscuits and for cheesecakes)cheesecakes)
Nutritive Value of Cheese• Contains practically all the nutrients found
in milk EXCEPT carbohydrates
• Lactose in milk is converted into lactic acid during the manufacturing of cheese
Effect of Heat on Cheese
• When cheese is heated, the fat melts and separates.
• Cheese becomes soft.
• On further heating, proteins over-coagulate and become stringy and tough.