What is rancidity? How can it be prevented? Give two everyday examples.

1. 1 · Define in one line. Rancidity is the oxidation of fats and oils in food, which changes their smell and taste.
2. 2 · Explain why it happens. Oxygen in the air slowly reacts with the oil in food and forms bad-smelling substances.
3. 3 · Give the methods.
   • Add antioxidants to fatty food.
   • Store food in airtight containers.
   • Fill packets with nitrogen to keep oxygen out.
   • Keep food in a cool place, such as a refrigerator.
4. 4 · Link to real life. Chip packets are puffed with nitrogen, and murukku and mixture are kept in airtight dabbas.
5. 5 · Close in one line. So rancidity is an unwanted oxidation that we slow down by keeping oxygen away.

Scoring tip: Give at least two methods, each with the reason "keeps oxygen away".