Can you describe what happens when milk is converted into curd or yoghurt, from your understanding of proteins.
Explanation Milk contains a protein called casien which is globular in nature. The characteristic white color of the milk is due to this same protein casien. The conversion of this globular protien into fibrous nature is carried out by a process called as fermentation. Curd or yoghurt contains a huge amount of lactic acid bacteria. These bacteria use enzymes to produce energy (ATP) from lactose, when added to the milk. Lactic acid is the byproduct of this ATP production. This lactic acid produced by the bacteria acts on globular casien proteins and converts them into fibrous proteins. This conversion leads to coagulation of proteins and gives a thick texture to the milk. As a result, the milk is converted into yoghurt or curd. Final Answer The conversion of globular protein casien in the milk, to its fibrous form by the action of lactic acid onto it leads to the formation of yoghurt or curd.
