Biochemistry of Sugars.

A sugar is a polyalcohol with at least one of them oxidized to either an aldehyde or a ketone. As a result, aldoses and ketoses are distinguished. The most simple sugar is glycerinaldehyde with a chain length of 3 carbons. Elongation of the chain leads from trioses to tetroses, pentoses, hexoses, heptoses, octoses, nonoses. Monosaccharides such as glucose, fructose, galactose, either alone or in combination with proteins or lipids, can build branched or unbranched carbohydrate chains of tremendous diversity. Carbon 5 sugars such as ribose and desoxyribose are ingredients for the RNA and DNA backbone structure. C6 sugars such as glucose, fructose, or galactose are key substrates for energy production, and for anabolic biosynthesis of structural elements such as cell walls. Their “fingerprint” is specific for cell lines and serves for instance as analyte to determine blood groups. Linkage to proteins and lipids mediates interactions among cells. Raw sugar is extracted from various plants such as sugar cane or sugar beet. Refining is the following process to remove the molasses. Cristallization yields the white sugar. Eating carbohydrates in turn will hydrolyse glycosidic bonds as far as physiological enzymes are available in human metabolism. The degree of hydroysis is also dependent on processing of meals. Risotto for example is slowly hydrolysed during the cooking process and the profile of carbohydrate fragments and free glucose depends on this procedure. Glucose liberated from various carbohydrates leads to different degrees of biologically availability, which is expressed as the glycemic index.
Keywords: Biochemistry, Glycemic Index, Monosaccharides, Polysaccharides, Sugars