Carbohydrates are organic substances of polyhydroxy aldehyde or ketone derivatives. They are classified into monosaccharide (glucose), disaccharides (sucrose), oligosaccharides (maltotriose) and polysaccharides. Polysaccharides are of homo (starch, glycogen, cellulose and inulin) and heteropolysaccharides (hyaluronic acid, dermatan sulfate, keratin sulfate and heparin). Carbohydrates form stereoisomers like D and L-sugars are referred to as enantiomers (mirror images of each other). Carbon 1 of sugars is anomeric carbon atom (a-D glucose and b-D-glucose). The isomers formed due to variations in the configuration of –H and –OH around a single carbon atom in a sugar molecule is called as epimers (mannose and galactose are 2 and 4 epimers of glucose respectively). Sucrose is nonreducing and also called invert sugar.