Question

Why do oils and fats become unfit for consumption if they are exposed to the atmosphere for a long time?

Answer 1

Rancidity of oil -

• If oils and fats are exposed to the atmospheric oxygen for a long time, get oxidised to form certain substance by which the smell and taste of oils changes and they become unfit for consumption.
• Addition of antioxidants (which prevent the oxidation of the substance) or keeping in air tight container or in atmosphere of nitrogen prevent rancidification of oil.