Question

Answer in detail.
You had eaten bread in the morning. Starting from the mouth, explain how it is digested?

Answer 1

Bread contains starch. The digestion of starch starts in the mouth. When we chew the bread, saliva gets mixed with it. It softens the food. Saliva is secreted by salivary glands. Saliva contains the enzyme salivary amylase (ptyalin) which acts on starch to convert it into maltose

starch \[\ce{->[salivary][amylase]}\] maltose.

After chewing, the food is swallowed into the pharynx. No further digestion takes place in the pharynx. From here the food moves in to the oesophagus, by peristaltic movements it is pushed in to the alimentary canal. In the small intestine (duodenum) rest of the starch is broken down into smaller units by pancreatic amylase. Further Maltose is changed into glucose by maltose in the small intestine (ileum).