Your Body is a Sophisticated Food Processor
The mechanical phase of digestion is responsible for sub dividing, mixing and propelling of food along the digestive tract. It includes chewing, swallowing, and the muscular activity of the walls of the digestive tract itself. The chemical phase of digestion is responsible for the final breakdown of food particles. It is brought about by digestive enzymes. Enzymes act as catalysts in the body. They increase the rate of a reaction without becoming part of the final reaction product. Digestive enzymes aid in the breakdown of large nutrient molecules into smaller molecules. For example, carbohydrates are changed into simple sugar, fats into glycerol, and fatty acids and proteins into amino acids.