STUDIES ON THE STRUCTURE OF PEA STARCHES .3. AMYLOPECTIN OF SMOOTH PEA STARCH

beta-Limit dextrins were isolated from smooth pea starch. It was shown by gel chromatography that the sample contained smaller limit dextrin s with a degree of polymerization (D.P.) of 40-4000 in addition to hig h-molecular-weight material. The smooth pea starch and the beta-limit dextrins were hydrolysed by the alpha-amylase of B. amyloliquefaciens and the molecular weight distribution of the reaction mixtures was ana lysed on Sepharose CL 6B. Initially the reaction was fast, but at late r stages branched dextrins with 10 similar to 60 were only very slowly hydrolysed further. In addition, linear dextrins with d.p. 2-10 were formed continously. Based on the branched dextrins produced from the b eta-limit dextrins a model of the structure of the amylopectin compone nt in smooth pea starch is suggested, in which clusters of defined siz es are regularly interconnected.