Biochemistry

а -Glucose a- Glucose (acyclic form) 0-Glucose ' (cyclic forms) Glucose is found in blood, lymph, cerebral fluid . It is widely distributed in products of plant origin, is found in large quantities in the fruits, seeds, leaves and flowers of plants , especially a lot of it (17-20%) in grape fruits . Glucose is a part of polysaccharides (glycogen, starch, fiber), disaccharides (maltose, sucrose, lactose, cellobiose). Upon the oxidation of the primary alcohol group, glucuronic acid is formed from glucose , and upon reduction, the hexatomic alcohol D is sorbitol . This reaction is used in the industrial production of sorbitol - a substitute for sweet carbohydrates in the diet of obese and diabetes. Ascorbic acid preparations are also obtained from glucose. D- fructose (levulose, fruit sugar) has acyclic and cyclic forms. HOCH OH « (acyclic form) a- D- fructose (cyclic forms) Fructose is a sweet carbohydrate: it is 2.5 times sweeter than glucose and 1.7 times sweeter than sucrose. In its free form, fructose is found in fruits, bee honey (45%); is an integral part of sucrose disaccharide and inulin polysaccharide . 143