a) The addition of baking soda (sodium bicarbonate) to fresh milk increases its pH from 6 to slightly alkaline (above 7) because baking soda is basic in nature. It acts as a buffer and neutralizes the acidic components present in fresh milk, such as lactic acid. This shift in pH towards alkalinity helps to stabilize the milk and increases its shelf life.
b) The milk takes a longer time to set as curd because baking soda, being alkaline, affects the protein structure in milk. The proteins in milk, primarily casein, are responsible for curdling or coagulating to form curd. When the pH of milk is alkaline, it interferes with the structure of proteins and hampers the curdling process. As a result, it takes a longer time for the milk to set as curd compared to when the pH is in the optimal range for curdling, which is slightly acidic.
A milkman adds a very small amount of baking soda to fresh milk.
a)Why does the pH of the fresh milk change from 6 to slightly alkaline
b)Why does this milk take a long time to set as curd.
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