Question

effects of acid on milk ​

Answer 1

In milk, casein is present at pH 6.6 as

calcium caseinate. When the acidity of milk

increases either by the addition of acid or by

natural souring, casein is precipitated e.g.

curdling. At higher temperature the addition of

acid hastens the coagulation of milk proteins.

Increase in acidity also hastens coagulation

of milk proteins. A very good example of this

phenomenon is the preparation of paneer, which

is prepared by adding lemon juice/citric acid to

hot milk, leads to separation of solids (proteins)

and liquids (whey).

Answer 2

A decrease in the milk natural pH affects the internal structure of the CM, as well as their external surface layers. Acidified milk decreases the net charge of caseins and causes the solubilization of colloidal calcium phosphate (CCP) from the micelles into the solution.