Question

When the fat or oil containg food materials are left for a long time,their smell and taste become change?​

Answer 1

When food containing fat or oil is not used and left over for a long time, their smell and taste changes because of fats and oils getting slowly oxidized. This process is called rancidity.

Two methods which are used to slow down the oxidation process are:

(i) keeping food in the airtight container.

(ii) flushing the bags containing food with nitrogen gas.