Compare the change of milk to curd with change of season ?
Answers
Answer:
Curd set faster in hot summer than in cold winter because the bacteria needs warmth to turn the milk into curd so in summer the temperature is hot which helps the bacteria to multiply faster which helps them to change the milk into curd but in winter the temperature is not warmth and favourable.
Answer:
In the setting of curd, milk changes into new substance, curd. This is an irreversible process that means milk cannot get back from curd. Formation of new substance and irreversible process shows that setting of curd is a chemical change.
Explanation:
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. Fermentation requires temperature range of 35–40 degrees Celsius.
The chemical reaction involved is :
C12H22O11 (Lactose) + H2O (Water) → 4CH3CHOHCOOH (Lactic Acid)
Hope it helps.