The Effects of Oxidation Reactions in Everyday Life

Rancidity is the spoilage of food caused by the oxidation of fats and oils, making the food undesirable for consumption. It leads to foul odour, unpleasant taste, and reduced nutritional value. Consuming rancid food may have harmful health effects.

Causes:

• Oxidation of fats and oils in food.
• Formation of highly reactive molecules responsible for bad odour and taste.
• Exposure to air, light, and heat accelerates the process.

Effects:

• Unpleasant odour and taste in food items like nuts, potato chips, and fried foods.
• Nutrient loss, making food less healthy.
• Health risks if consumed in large amounts.

Prevention:

• Adding antioxidants (substances that prevent oxidation) to food.
• Storing food in airtight containers to reduce exposure to air.
• Refrigeration to slow down oxidation.
• Replacing oxygen with nitrogen gas in food packaging, such as chip bags.

1. Initiation Reaction

External factors like heat and air trigger the reaction. This causes the formation of free radicals (highly reactive atoms or molecules with unpaired electrons).

RH → R + H**
(RH represents a fat molecule, and R is a free radical formed after losing hydrogen.)*

2. Propagation Reaction

The *free radical (R) reacts with oxygen (O₂), forming *peroxides (ROO). These peroxides further react with unsaturated fatty acids, producing more radicals, continuing the chain reaction.

R + O₂ → ROO** (peroxide formation)

3. Termination Reaction

The reaction stops when two radicals combine to form a stable single bond, preventing further oxidation.

ROO + ROO → End Products**

When fats and oils are oxidised, they become rancid and their smell and taste change.