FUNDAMENTALS OF FOOD TECHNOLOGY (1+1)

Lipids and its classification

LIPIDS

• The term ‘lipid’ is applied to a group of naturally occurring substances characterized by their insolubility in water, greasy feel and solubility in some organic solvents. They occur in the plant and animal kingdom.

Classification
Oils and fats:
These are esters of fatty acids and glycerol. Oils are liquid at 200C while fats are solid .

Compound lipids
They contain other organic compounds in addition to fatty acids and glycerol.

Phospholipids (phosphotides)
These contain phosphoric acid and nitrogeneous base in addition to fatty acids and glycerol e.g. (lecithin and cephalin)

Glycolipids
Compound lipids containing carbohydrates in combination with fatty acids and glycerol. e.g: cerebrosides

Waxes
These are esters of fatty acids and large chain aliphatic alcohols.

Derived Lipids
Substances derived from fat on hydrolysis or by enzyme activities are called derived lipids. Eg. fatty acids, alcohol

Fatty acids
Fatty acids in foods and in the body contain 4-24 carbon fatty acids

Short chain fatty acids- 4-6 carbon atoms
Medium chain fatty acids -8-12 carbon atoms
Long chain fatty acids- more than 12 carbon atoms

Fatty acids are divided into saturated fatty acid and unsaturated fatty acid

Saturated fatty acids
Saturated fatty acids have all the carbon atoms in the chain saturated with hydrogen atoms. eg. Palmitic, stearic, butyric acids

Unsaturated fatty acids
When a double bond is present between two carbon atoms the fatty acid is termed as unsaturated fatty acids. eg. Oleic acid

Poly unsaturated fatty acids
Three or more double bonds in a fat is called poly unsaturated fatty acids
eg. Linoleic, linolenic and arachidonic acid

Essential Fatty Acids

Nutritionally important fatty acids are known as essential fatty acids. Since the body cannot synthesize them the EFA must be supplied to the body.