Question

Digestion of food is an example of ……… (Physical /chemical) change.

Answer 1

Hint: A physical change refers to the change in physical properties like volume, density and physical state of the substance, while chemical change reveals about the changes in chemical properties like and chemical composition(from polysaccharide to monosaccharide) due to the enzymatic activity.
Conversion of triglyceride into glycerol and fatty acid is an example of chemical change while breakdown of complex solid form of food into small particles is an example of physical change.

Complete answer:
Digestion of food is an example of both physical and chemical processes. Digestion is the process in which complex forms of food are converted into smaller and absorbable forms with the help of enzymes (hydrolytic enzymes), so chemically digestion of food is a hydrolytic process.
Digestion is categorised into mechanical (physical) digestion and chemical digestion. Mechanical digestion is the breaking of ingested material into smaller pieces without changing its chemical structure (i.e., no enzymes are involved). Mechanical digestion mainly takes place in oral cavity which is called mastication or chewing by the activity of teeth and jaw muscles, and later on churning movement (peristalsis movement) in the stomach or intestine. This process mechanically reduces the volume and density of food particles to facilitate digestion.
Chemical digestion involves the activity of specific enzymes to break down the complex molecule into smaller molecules so they can be absorbed. Complex carbohydrate is hydrolysed into monomers like glucose with the help of enzyme amylase. In the intestine large peptides are converted into amino acids with the help of enzyme trypsin.

Note:
Mechanical digestion increases the surface area of ingested food so that enzymes can work on it more efficiently. Pancreas and liver secretes many digestive enzymes that promote hydrolysis of food in the intestine.