Question

Does digestion involve physical changes, chemical changes, or both? Explain

Answer 1

Digestion (assuming you asking human digestion system) is a combination of physical and chemical processes. The main goal is to let the ingredients of the food decay to smaller, absorb-able molecules and then separate it from the "rest". To support this, the food is mechanically cut to as small pieces as possible (chewing),this is a physical change because the size of the food particles was changed.

and then chemical reaction induced by both high pH and different enzymes from the saliva start working in the mouth. After the food enter the stomach and other parts of the digestive system, specialized enzymes, emulgators and the relatively extreme pH helps the hydrolization of carbohydrates, peptides and lipid , this is a chemical change.

We can also say Chemical digestion is considered a chemical change because enzymes in the stomach and intestines break down large macromolecules into simpler molecules so that the body can more easily absorb the food.

. Beside this chemical/physical process, there is a biochemical process, too: a wide range of microorganisms live in the digestive system, assisting with the undigested food, producing e.g. vitamins that the body can absorb.