RANCIDITY

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BY:

MR. SUMMIT SHARMA,

Department of Biotechnology,

HMV , Jalandhar

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21

Glycerol esters (acylglycerols)

• Triglycerides : most abundant family of lipids in plant and animal cells.
• major components of the the human diet

Glycerol

Triglyceride

Fatty acid

Classification

Contains one double bond

Contains more than one double bond

Functions OF PUFA :

1. Useful to prevent atherosclerosis.
2. Prostaglandin & eicosanoids are synthesized
3. They participate in structure of all cellular and subcellular membranes and the transporting plasma phospholipids.
4. Essential for skin integrity, normal growth and reproduction.
5. Important role in blood clotting.
6. Important in preventing and treating fatty liver.
7. Important role in health of the retina and vision.
8. They can be oxidized for energy production.

Deficiency: Their deficiency in the diet leads to nutritional deficiency disease. Its symptoms include:

1. Poor growth and health with susceptibility to infections, dermatitis,
2. Decreased capacity to reproduce,
3. Impaired transport of lipids, fatty liver,
4. Lowered resistance to stress.

Source: vegetable oils such as corn oil, peanut oil, olive oil, cottonseed oil, soybean oil and many other plant oils, cod liver oil and animal fats.

Property-Rancidity

Definition:

- It is a physico-chemical change in the natural properties of the fat leading to the development of unpleasant odour or taste or abnormal color particularly on aging after exposure to atmospheric oxygen, light, moisture, bacterial or fungal contamination and/or heat.

Types and causes of Rancidity:

1. Hydrolytic rancidity
2. Oxidative rancidity
3. Ketonic rancidity

1-Hydrolytic rancidity:

Due to hydrolysis of the fat

by lipase from bacterial contamination

at high temperature and moisture.

2-Oxidative Rancidity:

oxidation of fat or oil

Due to exposure to oxygen, light and/or heat

producing peroxide derivatives

that are toxic and have bad odor.

3-Ketonic Rancidity:

due to contamination with fungi

Moisture accelerates ketonic rancidity.

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COMPOUND (COMPLEX) LIPIDS

Esters of F.A with different alcohols but carry in addition other substances such as phosphate, nitrogenous bases, carbohydrates & proteins.

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Bibliography

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• Fundamentals of Biochemistry by J.L. JAIN
• Satyanarayana Biochemistry, 5^th Ed, Elsevier
• www.wikipedia.org
• www.brainly.in
• www.slideshare.net

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