Question

To determine the conditions needed for the setting of curd

Answer 1

Milk is converted into curd or yogurt by the process of fermentation. Milk consists of globular proteins called casein. The curd forms because of the chemical reaction between the lactic acid bacteria and casein. During fermentation, the bacteria use enzymes to produce energy (ATP) from lactose. The byproduct of ATP production is lactic acid. Lactic acid acts on the globular proteins present in the milk and denatures them. This denaturation destroys the tertiary and quaternary structures of proteins and the globular proteins are converted into fibrous proteins thus giving a thick texture to the milk due to coagulation of the proteins. The thick texture which is form is know as curd.

Answer 2

Answer:

EXPERIMENT-1--->To determine the conditions of setting of curd

Explanation:

Take three bowls and mark them 1,2 and 3.Pour 100 mL of lukewarm milk in each of the three bowls.

Add 1 teaspoon of curd in bowl 1 and mix properly.Cover the bowl and keep at room temperature.

Add 1 teaspoon of curd in bowl 2 and mix it properly.Keep it inside the refrigerator.

Let bowl 3 in like that condition and keep it at room temperature.

OBSERVATIONS--->It will be seen that curd forms only in bowl 1.This is because the starter curd contains Lactobacillus which helps the milk to set to curd.Lactobacillus multiplies only at room temperature.Thus,only a little amount of curd is added to milk as a starter to set the curd.