18-03-2014, 09:42 AM
MILK CHaEMISTRY
Milk components
The quantities of the main milk compnents can vary considerably depending on
the individual animal
b) stage of lactation,
c) age and health status
d)environmental conditions
influence milk composition.
The average composition of cows milk is shown in Table 1.
Milk fats
If milk is left to stand, a layer of cream forms on the surface. The cream differs considerably in appearance from the lower layer of skim milk.
Under the microscope cream can be seen to consist of a large number of spheres of varying sizes floating in the milk. Each sphere is surrounded by a thin skin,the fat globule membrane,which acts as
A) the emulsifying agent for the fat suspended in milk .
b) The membrane protects the fat from enzymes and prevents the globules coalescing into butter grains
Milk carbohydrates
Lactose is the major carbohydrate fraction in milk. It is made up of two sugars, glucose and galactose (Figure 3)
Homogenization
Purpose. The purpose of homogenization is to make more permanent and uniform emulation by reducing the fat globules to a very small diameter, not more than 1µ .
Homogenization is usually accomplished by forcing the liquid through a very small hole under suitable conditions of temperature and pressure (50°C and 200 ATM)