Biochemistry

Vitamin C is quickly destroyed when storing cooked meals hot. Re-heating also helps to reduce its content in food. On average, about 30% of the initial amount of vitamin C remains after cooking. Daily intake of vitamin C for adults is 50-75 mg. It increases when working in a very cold or hot climate, when exposed to physical or chemical harmful factors, increased or decreased atmospheric pressure, increased mental work, neuropsychic stress, excessive sweating, infectious and colds, and insufficient nutritional content amino acids in people working at night. Sources. Ascorbic acid is found in the green parts of plants (dill, parsley, lettuce, celery, onions, etc.), vegetables (peppers, potatoes, cabbage, tomatoes, etc.), berries (black currants, gooseberries, rowanberry, rose hips, sea buckthorn), citrus and other fruits. The important sources of vitamin C are potatoes, cabbage, and tomato paste in winter. Vitamin C in sauerkraut is much less than in fresh cabbage, especially if it is washed (for example, to reduce acidity). Valuable reserves of vitamin C can be prepared in the form of blackcurrant, mashed with sugar, pasteurized berries without sugar, rose hip, dried under gentle conditions. 12.3 FAT-SOLUBLE VITAMINS This group combines fat soluble vitamins: retinol, calciferols, tocopherols, phylloquinones and others. The body needs a certain amount of fat to absorb fat-soluble vitamins. Fat-soluble vitamins can accumulate in the body tissues, synthesized from compounds close to them in structure. For example, calciferol is formed in the skin from body lipids (7-dehydrocholesterol) under the influence of sunlight or light from a quartz lamp; phylloquinones - in the intestine with the participation of certain microorganisms, vitamin A - from the provitamins p-carotene and carotenoids from plant foods (from Latin corota - carrots). Retinol (Vitamin A, anti-xerophthalmic factor). Vitamin A was studied in 1913 and synthesized in 1933. Structure and physicochemical properties. Vitamin A has several vitamers (A! , A 2 , A 3 ), etc., of which vitamin Ai is most common. Н,\ /СН, CHj CH, H/X^C-CH-CH-C-CH-CH-CH-OCH-CHjOH Retinol (Vitamin Aj) 261