Explain how blanching affects the enzyme, polyphenoloxidase and can be used to prevent the browning of fruits.

Polyphenoloxidase is an enzyme present in many types of
foods like fruits, vegetables, mushrooms, etc. It plays a role in protecting the plants
from bacteria and viruses and enables them to withstand adverse weather
conditions.

This enzyme acts as a catalyst in a reaction
that takes place when fruits are cut. The reaction leads to the formation of dark
polymers known as melanins which discolor the foods and lead to their
browning.

Browning can be reduced to a large extent by
rendering the enzyme inactive. This is down by heating it. Polyphenoloxidase is
destroyed when food is heated to temperatures above 100 degree Celsius. Blanching can be
done either by scalding the food by exposing it to hot water or steam, or it can be
achieved by microwaving the food.