Have you observed a foul smell in nuts that have been stored for months? Or potato chips that have been sitting in the kitchen cupboard for too long? When such foul odour emanates from food it is said to be rancid.In simple terms, rancidity is the spoilage of food such that it becomes unsuitable and undesirable for consumption.
Food turns rancid when the fats and oils within them get oxidized and the taste and smell of the food changes. Oxidation of fats generates highly reactive molecules in the rancid food which is responsible for the unpleasant odour and flavour. These chemical reactions also reduce the nutrition of the food. Some studies show that rancid food can have harmful health effects if consumed.
Rancidity can be prevented using the following methods:
Adding antioxidants (substances which prevent oxidation) to food.
Storing food in airtight containers to slow the process of rancidification.
Refrigerating food also helps to slow down rancidification.
Replacing oxygen in the containers with another gas. For example, to prevent chips from turning rancid, chips manufacturers flush the bags with nitrogen gas.