What is the pH of milk? How does the pH change when milk is converted into curd? Explain.

The acidic solution is a solution whose pH is less than the neutral pH value(7) and the solution having a pH value greater than the neutral pH is a basic solution.

pH of milk: Milk is slightly acidic in nature and has a pH value equal to 6.

Conversion of milk to curd:

• The enzyme Lactobacillus converts milk to the curd.
• During the conversion of milk to curd, Lactic acid is produced which reduces the pH of the solution that causes the milk protein to coagulate.

Both milk and curd are acidic, just the difference is milk is slightly acidic while the curd is more acidic.

Therefore, the pH of milk is 6(slightly acidic) while that of curd is in the range 4.5 - 5.5(more acidic).