When only one anomeric carbon is involved in glycosidic bond formation, reducing disaccharides are formed.This hydroxyl group present in one monosaccharide reacts with any one of the hydroxyl groups attached to C-1, C-2, C-3, C-4, or C-6 of another monosaccharide to produce 1→1, 1→2, 1→3, 1→4, and 1→6 linked disaccharides.The hydroxyl group formed as a result of hemiacetal formation is highly reactive when compared to other hydroxyl groups.Disaccharides consist of two monosaccharides joined covalently by an O-glycosidic bond.The physiologically important disaccharides are maltose, lactose, trehalose and sucrose.The oligosaccharides commonly encountered in nature belong to disaccharides. It is hydrolysable by acids to glucose with difficulty. It is stored as a reserve food supply in insect's hemolymph Relatively stable to reaction with dilute alkali.įungi and yeast. Hydrolysed by dilute acids or enzyme invertase (sucrase) to one molecule of glucose and one molecule of fructose. Sugar beet, sugarcane, sorghum and carrot rootsįermentable. Hydrolysed to one molecule of galactose and one molecule of glucose by acids and the enzyme lactase. It shows reactions of reducing sugars including mutarotation. In trace amounts it can be seen in urine during pregnancy Hydrolysed to two molecules of D-glucose. Fermentable by enzyme maltase present in yeast. BIC 101 :: Lecture 03 :: STRUCTURE OF DISACCHARIDES & POLYSACCHARIDESĬomposition, Sources and Properties of common disccharidesįorms osazone with phenylhydrazine.
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