Cereal Chem 58:496 - 502.  |  VIEW ARTICLE
Structural Characterization of Legume Starches. I. Studies on Amylose, Amylopectin, and Beta- Limit Dextrins.

C. G. Biliaderis, D. R. Grant, and J. R. Vose. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

Nine purified legume starches (from smooth and wrinkled peas; adzuki, garbanzo, mung, red kidney, navy, and faba beans; and green lentil) were fractionated into their amylose and amylopectin components. The fine structures of the isolated starch components and starch beta-limit dextrins were investigated using hydrolytic enzymes (pullulanase, beta-amylase, and glucoamylase) in conjunction with gel filtration chromatography (Biogel P-10). The unit-chain profiles of the debranched legume amylopectins were characterized by two overlapping distributions with average degrees of polymerization of 45-55 (II-chains) and 14-18 (III-chains). The average chain length for most of these amylopectins ranged from 20 to 26. Wrinkled pea starch contained branched polysaccaride molecules with a chain length greater than that of normal amylopectin. The limiting viscosity numbers of the legume amylose fractions ranged from 136 to 251 ml/g. The incomplete beta-amylolysis of the legume amyloses (78.4-89.4%) was due to the presence of a relatively small number of alpha-(1-6) linkages in the molecule. A hypothesis was developed to explain starch gelatinization and granule rigidity based on the molecular characteristics of the branched polysaccharide fractions of these starches.