Question

What is the use of keeping food in air tight containers?

Answer 1

Hint: The opened food tests and odor bad. The opened food becomes rotten in presence of air, moisture, bacteria, and light.

Step by step answer: The deterioration of food is known as rancidity. The main cause of rancidity is oxidation and hydrolysis.
The opened food is oxidized or hydrolysed by several factors such as air that is known as aerial oxidation, by moisture, bacteria, and light. These factors generate active free radical and oxygen precursors.
These factors cause the oxidation of lipids, fats, and oils. The change in the structure of lipids, facts, and oil deteriorate the food.
The chemical change has shown in form of some physical change mainly as undesired odor and teste or in colour.
Rancidity also decreases the nutritional value of food such as it destroys the many vitamins of food.
When the food is kept in airtight containers it cannot react with air thus prevented from deterioration.
The food can be prevented by using some methods:
The use of antioxidants such as ascorbic acid, antioxidants stops the oxidation.
Storage of the food in the refrigerator.
Storage of food in an inert environment.
Use of some substances that prevent food to spoil and increase the nutritional value such as fish oil.
The storage of food in a sterilized airtight container is known as canning.


Note: The storing the food in an airtight container or refrigerator slows down the oxidation process hence rancidity. Some food such as aged cheese is also an example of rancidity but that flavoured is the desired flavour.