Explain the following terms with one example each:
(a) Corrosion (b) Rancidity

Explanation

Rancidity: When fats and oils are exposed to air, they get oxidised and become rancid and their smell and colour change. This phenomenon is called rancidity. To prevent rancidity of food materials containing fats and oils, certain substances (called antioxidants) are added which prevent oxidation and hence rancidity. Some food materials are stored in air tight containers or the bags containing the food materials (such as chips) are flushed with inert gas such as nitrogen to prevent them from getting oxidised.