Which one of the following enzymes carries out the initial step in the digestion of milk in humans?
- Trypsin
- Pepsin
- Rennin
- Lipase
Answer
(3) Rennin
Solution
Milk is first digested in the stomach, where the milk protein casein is coagulated (curdled).
As per NCERT, rennin is a proteolytic enzyme found in the gastric juice of infants which helps in the digestion of milk proteins.
Rennin carries out the initial step (curdling of milk: caseinogen paracasein, which forms calcium paracaseinate); pepsin then digests the curdled proteins.
Trypsin acts later in the small intestine and lipase digests fats.
Answer: (3)