Neutral fats (TG) are all triesters of the trihydric alcohol, glycerol with various fatty acids. The type formula for a neutral fat (TG) is given in (Fig. 4.9), in which R1 R2 R3 represent fatty acid chains which may or may not all be the same. Naturally occurring fats have apparently the D-structural configuration. Physical Propeies 1. Neutral fats are colourless, odourless and tasteless substances. The colour and taste of some of the naturally occurring fats is due to extraneous substances. 2. Solubility: They are insoluble in water but soluble in organic fat solvents. 3. Specific gravity: The specific gravity of all fats is less than 1.0, consequently all fats float in water. 4. Emulsification: Emulsions of fat may be made by shaking vigorously in water and by emulsifying agents such as gums, soaps, and proteins which produce more stable emulsions. Biomedical Impoance of Emulsification The emulsification of dietary fats in intestinal canal, brought about by bile salts, is a prerequisite for digestion and absorption of fats. 5. Melting point and consistency: The hardness or consistency of fats is related to their MP glycerides of lower FA melt at lower temperature than those of the higher fatty acids, and the unsaturated fatty acids glycerides at still lower temperature. Chemical Propeies 1. Hydrolysis The fats may be hydrolysed with: * Superheated steam, * By acids, or alkalies, or * By the specific fat spliting enzymes lipasesRef: Textbook of Medical Biochemistry Eighth Edition Dr (Brig) MN Chatterjea pg no:52-53