CLASSIFICATION AND PROPERTIES OF FATS AND THEIR FUNCTIONS

CLASSIFICATION AND PROPERTIES OF FATS AND THEIR FUNCTIONS
ANIMAL NUTRITION
LIPIDS

1. Submitted to : Submitted by : Dr. M. R. CHAVDA TATHAGAT P. KHOBRAGADE Assistant Professor MVSc (Ani. Nutrition) Animal Nutrition I yr Polytechnic In A.H COVSAH KU, Junagadh KU, Junagadh ANN - 601 NUTRITIONAL BIOCHEMISTRY 1+0 M.V.Sc DEPARTMENT OF ANIMAL NUTRITION COLLEGE OF VETERINARY SCIENCE AND ANIMAL HUSBANDARY, KAMDHENU UNIVERSITY, JUNAGADH CLASSIFICATION AND PROPERTIES OF FATS AND THEIR FUNCTIONS

2. Learning Objectives:- INTRODUCTION LIPIDS AND THEIR CLASSIFICATION FATS FATTY ACIDS STRUCTURE OF FATS PROPERTIES OF FATS FUNCTION OF FATS OTHER LIPIDS

3. Food is that which nourishes the body. Food may also be defined as anything eaten or drunk, which meets the needs for energy, building, regulation and protection of the animal body. Nutrition is the process of providing or obtaining the food necessary for health and growth. Nutrition includes everything that happens to food from the time it is eaten until it is used for various functions in the body. Nutrients are components of food that are needed by the body in adequate amounts in order to grow, reproduce and lead a normal, healthy life. Nutrients include Water, Proteins, Fats, Carbohydrates, Minerals And Vitamins.

4. Lipids (Greek: lipos–fat) are of great importance to the body as the chief concentrated storage form of energy, besides their role in cellular structure and various other biochemical functions. As such, lipids are a heterogeneous group of compounds and, therefore, it is difficult to define them precisely. Lipids may be regarded as organic substances relatively insoluble in water, soluble in organic solvents (benzene, ether etc.), actually or potentially related to fatty acids and they are utilized by the living cells. In animals, Lipids are the major form of energy storage, mainly as FAT, which may constitute up to 97 % of the adipose tissue of obese animals.

5. FATS In  nutrition ,  biology , and  chemistry ,  fat usually means any  ester  of  fatty acids , or a mixture of such  compounds , most commonly those that occur in living beings or in food . The term ‘ fat ’ is frequently used in a general sense to include both groups i.e vegetable oils and animal fat , Both have the same general structure but have different physical and chemical properties. Solid fats :- solid at room temperature like butter or lard , mainly come from animal foods, Solid fats contain more saturated fats. Oils :- liquid at room temperature like olive oil , have lower melting point than solid fat. Fats major function is to supply energy and stored fat is important as a thermal insulator.

6. Fats are esters of fatty acids with the trihydric alcohol glycerol, and are also referred to as glycerides or acylglycerols. When all three alcohol groups are esterified by fatty acids, the compound is a triacylglycerol (triglyceride). STRUCTURE OF FATS Here R represents the residue of fatty acid , if all the 3 residue are same they are called simple triglyceride. R1, R2 and R3 represent the chains of different fatty acids, so they are called as mixed triglyceride.

7. Saturated fatty acids do not contain double bonds , while unsaturated fatty acids contain one or more double bonds . The unsaturated acids contain either one (monoenoic), two (dienoic), three (trienoic) or many (polyenoic) double bonds . Fatty acids with more than one double bond are frequently referred to as polyunsaturated fatty acids (PUFA). The unsaturated acids possess different physical and chemical properties from the saturated: they have lower melting points and are more chemically reactive. FATTY ACID Fatty acids are carboxylic acids with hydrocarbon side chain. They are the simplest form of lipids.

8. SATURATED FATTY ACIDS Saturated fatty acids do not contain double bonds. High melting point Solid state in room temperature Foods sources of saturated fats are whole milk, butter, cheese, coconut oil, vegetable oil, meat fat, peanut, fried foods, etc. Palmitic acid n-Hexadecanoic acid 16C CH3(CH2)14COOH Stearic acid n-Octadecanoic acid 18C CH3(CH2)16COOH Arachidic acid n-Eicosanoic acid 20C CH3(CH2)18COOH UNSATURATED FATTY ACIDS The unsaturated acids contain either one (monoenoic), two (dienoic), three (trienoic) or many (polyenoic) double bonds. Good for consumption (Leads to formation of HDL Cholesterol) Low melting point Liquid state in room temperature Foods sources of unsaturated fats are walnuts, flax, avocado, sunflower oil, soybean oil, fish oil, red meat fat, etc.

9. Oleic Acid 18C 1 Double Bond Linoleic Acid 18C 2 Double Bond Linolenic Acid 18C 3 Double Bond Arachidonic acid 20C 4 Double Bond The fatty acids that cannot be synthesized by the body and, therefore, should be supplied in the diet are known as essential fatty acids (EFA). Chemically, they are polyunsaturated fatty acids, namely linolenic acid ( omega-3 fatty acid) and linoleic acid ( omega-6 fatty acid ). Linoleic acid and linolenic acid are thus dietary essentials. Omega-3 Fatty Acids - Fish and other seafood , Nuts and seeds (such as flaxseed, and walnuts) Omega-6 Fatty Acids – Sunflower, Peanut, Corn, Soyabean, Egg

10. PROPERTIES OF FATS Hydrolysis Fats may be hydrolysed by boiling with alkalis (like KOH) to give glycerol and soaps Such a hydrolysis is termed saponification since it produces soaps, which are sodium and potassium salts of the fatty acids. Oxidation The unsaturated fatty acids readily undergo oxidation at the carbon atom adjacent to the double bond to form hydroperoxides. The products of oxidation include shorter-chain fatty acids, fatty acid polymers, aldehydes , ketones , epoxides (cyclic ethers) and hydrocarbons . Oxidation of saturated fatty acids results in the development of a sweet, heavy taste and smell, commonly known as ketonic rancidity.

11. Antioxidants Natural fats possess a certain degree of resistance to oxidation, due to the presence of compounds termed antioxidants (which can be phenols, quinones, tocopherols etc). These antioxidants prevent the oxidation of unsaturated fats until they themselves have been transformed into inert products. The most important naturally occurring antioxidant is vitamin E, which protects fat by preferential acceptance of free radicals. Hydrogenation This is the process whereby hydrogen is added to the double bonds of the unsaturated acids of a fat , thereby converting them to their saturated analogues. Use to produce saturated fat with higher melting points (H ardening ) Ex. Margarine Dietary fats are highly unsaturated, but the body fats are highly saturated in case of ruminants due to hydrogenation by rumen microbial activity.

12. Fats perform several important functions:-

13. COMPOUND LIPID S A) GLYCOLIPIDS In these compounds, two of the alcohol groups of the glycerol are esterified by fatty acids and the other is linked to a sugar residue . Glycolipids (glycosphingolipids) are important constituents of cell membrane and nervous tissues (particularly the brain). They can be Glucolipids or Galactolipids. Rumen microorganisms are able to break down the galactolipids to give galactose, fatty acids and glycerol. This are glycerol based lipids which are ester of fatty acids containing other groups like Sugar ( Glycolipids ), Phosphate ( Phospholipids ), etc.

14. B) PHOSPHOLIPIDS The role of the phospholipids is primarily as constituents of the lipoprotein complexes of biological membranes . They are widely distributed, being particularly abundant in the heart, kidneys and nervous tissues. The phospholipids contain phosphorus in addition to carbon, hydrogen and oxygen. Phosphoglycerides :- These are esters of glycerol in which only two of the alcohol groups are esterified by fatty acids, with the third esterified by phosphoric acid. The most commonly occurring phosphoglycerides in higher plants and animals are lecithins and cephalins .

15. Lecithins : These are the most abundant group of phospholipids in the cell membranes. Cephalins : Ethanolamine is the nitrogenous base present in cephalins. Thus, lecithin and cephalin differ with regard to the base. Cephalins are found in most cell membranes, particularly in brain tissues. WAXES Waxes are simple, relatively non-polar lipids consisting of a long-chain fatty acid combined with a monohydric alcohol of high molecular weight. They non nutritive , solid at ordinary temperatures , protective function. Waxes are widely distributed in plants which lead to overestimation of ether extract. Waxes are resistant to breakdown and are poorly utilized by animals. Natural waxes are usually mixtures of a number of esters . Ex. Beewax

16. STEROIDS The steroids include such biologically important compounds as the sterols, the bile acids, the adrenal hormones and the sex hormones. Cholesterol :- Cholesterol is a zoosterol that is present in all animal cells. It has a low solubility in water, and is important as a constituent of various biological membranes. It is present in abundance in nervous tissues as insulating cover. It is precursor for Vit D, B ile acids, Sex hormones like estrogens , testosterone etc. Cholesterol is very insoluble, and prolonged high levels in blood result in its deposition on the walls of the blood vessels.

17. REFERENCES P McDonald et al. : Animal Nutrition Book (eighth edition). U. Satyanarayan et al. : Biochemistry Book (fourth edition). Nalini Pandey : Fatty acids and lipids. THANK YOU !