Biochemistry

sugar), which, on the one hand, are poor in thiamine, and on the other, increase the need for it. Thiamine deficiency can occur with an unbalanced dietary protein, an insufficient content of a number of vitamins (С, В 2 , В 6 , etc.) in the diet with profuse sweating, exposure to harmful occupational factors, great physical exertion, and psychological stress. Vitamin В i deficiency can also be caused by various diseases that interfere with its absorption upon ingestion or alter metabolism. The development of vitamin В t deficiency is promoted by anti-vitamin factors present in food products, in particular, such properties are inherent in thiaminases contained in meat and internal organs of freshwater and marine fish. Some plant products also have anti-vitamin activity - tea, coffee, Brussels sprouts, blueberries and black currants. Some vitamins can be destroyed during cooking. This is facilitated by a slightly alkaline environment. The average loss of thiamine in the process of cooking food is about 25 %. Daily thiamine intake is about 1 mg / 1000 kcal (1.4-2.4 mg). It increases in women in the second half of pregnancy, during breastfeeding, in cold (for example, Far North regions) and hot climates, in people working at high temperatures, exposed to chronic effects of industrial poisons (lead, arsenic, etc.), engaged in intense mental work, performing heavy physical work. A great need for vitamin B] is observed in patients with impaired cardiovascular and central nervous system functions, decreased digestive tract function, and in people taking antibiotics. An increase in the amount of carbohydrates, proteins and fats in the diet also causes an increase in the body's need for vitamin B t Sources. Rich in thiamine, rye and wheat bread made from wholemeal flour, various cereals (buckwheat, oatmeal, etc.), legumes (peas, beans, lentils, soybeans), potatoes, various vegetables, walnuts, peanuts, hazelnuts. Thiamine is also found in animal products, most of all in various types of meat, especially pork and By-products. Valuable sources of thiamine are yeast and bran. To increase the vitamin value of dishes that are offered in food establishments, it is recommended to use vegetable decoctions enriched with yeast, soy flour, milk powder, and cereal embryos. Riboflavin (vitamin B 2 , antiseborrheic factor). This vitamin was first found in milk, so it is sometimes called lactoflavin. Structure and physicochemical properties. Riboflavin belongs to the group of flavones. Solutions of this bright yellow vitamin were obtained in the last century, but only in 1932 the preparation was isolated in concentrated form, and then synthesized in 1935. Riboflavin is 6,7-dimethyl-9-ribitylisoalloxazine. 248