Classification, structure, properties and functions of fatty acids, essential fatty acids, fats, phospholipids, sphingolipids, cerebrosides, steroids, cholesterol, plant sterols, bile acids, prostaglandins, lipoamino acids, lipoproteins, proteolipids, lipopolysaccharides. Classification of fatty acid based on Carbon number, position of double bond, saturation, unsaturated, conjugated position in triglycerides. Reactions of lipids, oxidative and hydrolytic rancidity. Different types of fats, uses in food processing, food emulsions, fat replacers. Changes during food processing. Protein lipid interaction, Lipid Carbohydrate interaction, Lipid-Lipid interaction.