Question

11. Lipids experience oxidation explainS the process. and indicates how you would prevent this process. (20 points)

Answer 1

The oxidative degradation of lipids are called as lipid peroxidation. In this process, the free radicals present takes up electrons from lipids, thereby resulting in cell damage. Since it involves a free radical, it follows a free radical chain reaction mechanism. This process occurs mainly in polyunsaturated fatty acids due to the presence ofultiple bonds.

The three major steps involved in this radical mechanism is: inititation, propagation and termination.

1) Initiation

Here the fatty acid radical is formed.

Examples for radical initiators are reactive oxygen species like OH^. And HOO^.

2) Propagation

Here the fattyl acid radical reacts with oxygen to form peroxy-fatty acid radical which then reacts with other fatty acids to form all these radicals and this cycle continues.

3) Termination

Termination occurs when 2 radical species reacts to form a non-radical species. In our body vitamin c and E are important antioxidants present to serve this purpose.

How to prevent this process?

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This process can be prevented by antioxidants such as vitamin C and vitamin E. The role of antioxidants is to inhibit the accumulation of free radicals by breaking down the lipid peroxide to water and oxygen.