Maya forgot a bowl of milk overnight on the Windowsill. Next day the milk had changed to curd. Why do you think this happened? ( Hint: Milk contains Microbes)
Answers
Answer:
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.
plz mark me as a brainiliest
When Maya kept the milk out in room temperature(windowsill) it was immediately attacked by bacteria.(Streptococci). These bacteria are found in air, in the vessel lid or even in boiled milk . They rot the milk (act on milk for their own nourishment) and the lactose in milk is changed to lactic acid. This acid curdles milk protein casein immediately and it gets denatured. So what is left is white curdled spoilt milk and a clear water like lactic acid.
This curd is spoilt protein, not the good and tasty curd we make with curd bacteria called Lactobacillus. Lactobacillus is not found in air. It is found only in old curd. That is why we add a little curd in luke warm milk to make new curds.
HOPE THIS HELPS :D