A chemical change is a change that results in the formation of new chemical substances by changing the chemical composition of the substance.
It involves the making or breaking of bonds between atoms.
Generally, chemical changes are irreversible.
For example, burning paper and wood, food digestion, and egg boiling.
Cooking of food:
Food cooking is a chemical change because vegetables and raw ingredients are converted to delicious food which can not be converted back to orignial ingredients.
Hence, cooking of food is an example of chemical change.