Biochemistry

Wax protects leaves and fruits from the penetration of water and germs, it is found in capsules of tubercle bacilli. Honey is stored under a layer of beeswax. The most important components of fats, which largely determine their properties, are fatty acids. Fatty acitZs usually contain an even number of carbon atoms and an unbranched chain. They are divided into two large groups: saturated (limiting) and unsaturated (unsaturated) containing double bonds. It is from the double bonds in the molecule that all the basic properties of unsaturated fatty acids depend. Fatty acids are part of animal fats. In human tissues, unsaturated fatty acids are present, which belong to the families: oleic, linoleic and linolenic acids . At the same time, human tissues are not able to synthesize linoleic and linolenic acids, but must receive them with food, and therefore they are attributed to essential nutritional factors. All other polyunsaturated fatty acids (PUFAs) are formed by chain extension or the introduction of new double bonds. The following fatty acids are of greatest importance in terms of distribution and properties: saturated'. butyric (C4 ) palmitic (Сіб) stearic (Cig) CH 3 -(CH 2 )2-COOH CH 3 -(CH 2 ) !4 -COOH CH 3 -(CH 2 ) ]6 -COOH monounsaturated (with one double bond): oleic (Cig) CH 3 - (CH 2 ) t - CH=CH - (CH 2 ) 7 - COOH polyunsaturated (with two or more double bonds): linoleic (C i 8 )CH 3 -(CH 2 ) 4 -CH f CH-CH 2 -CH=CH-(CH 2 ) 7 -COOH linolenic (Cig) CII 3 - CH 2 -CH=CH-CH 2 -CH=CH-CH-CH=CH- (CH 2 ) 7 -COOH arachidonic (C 2O )CH 3 -(CH 2 ) 4 -CH=CH-CH 2 -CH=CH-CH 2 -CH=CH- CH 2 -CH=CH-(CH 2 ) 3 - COOH (C 3 H 7 COOH) (Ci 5 H 31 COOH) (Ci 7 H 33 COOH) (C1 7 H 33 COOH) (C, 7 H 3 1COOH) (C1 7 H 29 COOH) (C t9 H 31 COOH) The systematic names of a number of natural fatty acids are given in table 6.1 . Unsaturatedfatty acids are found in liquid fats (oils). In many vegetable oils, their content reaches 80-90% (sunflower, com, linseed, olive). Due to the fragile double bonds between carbon atoms, unsaturated fatty acids easily enter into chemical reactions. By hydrogenating vegetable fats, margarines are obtained in industry. 127