Biochemistry

P-glucose P-glucose Cellobiosis Among natural trisaccharides, raffinose containing fructose, glucose and galactose is of the greatest importance. In significant quantities, it is found in sugar beets , cotton seeds, seaweeds, mushrooms and other plants . A typical representative of tetrasaccharides is stachyose, consisting of two galactose residues, one glucose molecule and one fructose. It is found in large quantities in the bulbs and roots of some plants, in the seeds of legumes. Polysaccharides. These are high molecular weight carbohydrates, consisting of a large number of monosaccharides. They have hydrophilic properties and, when dissolved in water, form colloidal solutions. Polysaccharides are divided into homo- and heteropolysaccharides. Homopolysaccharides. They include monosaccharides of the same type. For example, starch and glycogen are built only from glucose molecules, inulin - from fructose. The most important homopolysaccharides are starch, glycogen, fiber (cellulose), consisting of residues of glucose molecules, as well as pectin substances . The inulin polysaccharide was built from the residues of fructose molecules , mannans contain the remains of mannose molecules, galactans - galactoses. Starch is a mixture of a linear polysaccharide - amylose (10-30%) and amylopectin (70-90%), having a branched structure, the general formula of which is (C 6 H ia Of) n . This polysaccharide is constructed of glucose residues connected in amylose and amylopectin linear chains a-l,4-linkages, the branching points in amylopectin - me zhtsepochnymi a-l,6-bonds (see Figure 7.1). Starch is a product of photosynthesis and the main nutrient of plants. It accumulates in the form of starch grains in leaves, tubers, fruits. The starch content in wheat seeds is high (75-80%), significantly lower in rice (30%), potato tubers (25%). 147