Describe the nature of the enzymatic digestion that occurs in the mouth; in the stomach. Where does most enzymatic digestion actually occur?
Enzymatic digestion of starches begins in the mouth. Yet the amylase secreted by the saliva glands into the oral cavity only breaks down starches into double sugars and not all the way into glucose. Further, the amylase is only able to break down a small percentage of the starches present before the food arrives in the stomach, where the acidic environment quickly inactivates the amylase. Enzymatic digestion of proteins begins in the stomach. The gastric glands of the mucosa of the stomach wall secrete pepsin which functions under the very acidic conditions produced by the hydrochloric acid the stomach lining also secretes. Yet pepsin does not hydrolyze proteins completely into individual amino acids but splits only a few select peptide bonds. Most enzymatic digestion of sugars and proteins and all the breakdown of fats occurs in the small intestine.
