12
Question Question 12
A milkman adds a very small amount of baking soda to fresh milk.
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?
(a) To prevent the milk from turning sour and spoiling due to lactic acid formation, the milkman shifts its pH from 6 to slightly alkaline by adding baking soda.
(b) For this milk to set as curd, the lactic acid formed during curdling process needs to first neutralise the baking soda added. Hence, it takes longer time to set as curd.