IUPAC 名称
6-(hydroxymethyl)oxane-2,3,4,5-tetrol
描述
Stored in all parts of plants as insol. granules. Coml. starches come mainly from corn (maize), sorghum grains, tapioca root and potato tuber. Most starch samples contain 20 ± 5% Amylose which can be pptd. from aq. starch soln. with, e.g., Thymol. Various uses in food processing including thickener, stabilizer, flavour modifier, filler for baking powder, flour additive, firming agent and release/antisticking agent. Many modified forms also used
Amylose is a linear polymer of glucose linked mainly by ?(1?4) bonds. It can be made of several thousand glucose units. It is one of the two components of starch, the other being amylopectin. Amylose is soluble in water.; Amylose is defined as a linear molecule of (1→4) linked alpha-D-glucopyranosyl units, but it is today well established that some molecules are slightly branched by (1→6)-alpha-linkages. ; The oldest criteria for linearity consisted in the susceptibility of the molecule to complete hydrolysis by beta-amylase. This enzyme splits the (1→4) bonds from the non-reducing end of a chain releasing beta-maltosyl units, but cannot cleave the (1→6) bonds. When degraded by pure beta-amylase, linear macromolecules are completely converted into maltose, whereas branched chains give also one beta-limit dextrin consisting of the remaining inner core polysaccharide structure with its outer chains recessed.; Starches of different botanical origins possess different granular sizes, morphology, polymorphism and enzyme digestibility. These characteristics are related to the chemical structures of the amylopectin and amylose and how they are arranged in the starch granule. (PMID 9730163). Amylose is found in many foods, some of which are taro, alcoholic beverages, rice, and potato.