What is meant by rancidity? How can it be prevented?

Hint: Food items are perishable and get spoiled when exposed for a longer time to the atmosphere or moisture in air. Foods contain nutrients in the form of carbohydrates, proteins and fats. Among them fats are responsible for spoiling the food due to their reaction in the atmospheric oxygen and moisture. This results in food being rancid.

Complete answer:
Food consists of various components like carbohydrates, proteins etc. Some of them are fats and oils. When the food containing fats and oil is exposed in the atmosphere for a very long time, then oxidation occurs in the fats. This oxidation results in spoiling the food by changing its taste and odor. This spoilage of food is called rancidity and the food is called rancid.
Rancidity is because; fats and oils are unsaturated fatty acids that get converted into saturated ones by addition of oxygen through oxidation. This oxidation results in spoilage by altering the chemical composition of food.
Rancidity can be prevented by:
-Addition of anti – oxidants in food items. This anti – oxidants does not allow the free radicals of oxygen to get involved in food. For example adding nitrogen gas to a chips packet.
- Keeping the food items in airtight containers that can prevent the exposure to air, hence minimizing the oxidation.
Hence, rancidity is the oxidation of fats in food. It can be prevented by adding anti – oxidants.

Note:
Addition of anti – oxidants is one of the techniques of food preservation. Some common anti – oxidants are butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA) that is added in butter, sulphur dioxide and sulfites are added in wines and sugar syrups to prevent oxidation.