Studies on sweet potatoes-III. Distribution of unit chains of branched and unbranched molecules of starch

Madhusudhan, B. and Gowda, L. R. and Tharanathan, R. N. (1996) Studies on sweet potatoes-III. Distribution of unit chains of branched and unbranched molecules of starch. Food Chemistry, 57 (2). pp. 201-204. ISSN 0308-8146

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Abstract

<p align="justify">Freshly prepared sweet potato (SP) starch was separated quantitatively into amylose and amylopectin by a concanavalin A precipitation method. Amylose was further fractionated into two subfractions containing essentially linear (Am) and moderately branched (Ax) molecules, by hot-butanol extraction. The mole- cular weight determined by GPC of Am was 3 x 106 Da, the values for Ap and Ax were 1.5x lo7 and 5 x 1O6 Da, respectively. The Beta-amylolysis limit values were 57, 70 and 92%, respectively, for Ap, Ax and Am. The native, as well as the derived Beta-limit dextrins of Ap and Ax, were debranched with isoamylase and their unit - chain lengths, measured by GPC and SE-HPLC methods, showed Ap (CL, 21.0)to have a trimodal distribution of unit chains with m values of 52, 37 and 20, -whereas Ax had tetramodal unit chains with DP values of 40, 30, 21 and 9. Am was more or less a linear molecule. In vitro SP starch was more digestible than legume and cereal starches.</p>

Item Type:	Article
Subjects:	600 Technology > 08 Food technology > 23 Vegetables > 02 Potato
Divisions:	Dept. of Biochemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	07 Jun 2005
Last Modified:	28 Dec 2011 09:24
URI:	http://ir.cftri.res.in/id/eprint/2

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