Complex formation between starch and stearic acid: Effect of enzymatic debranching for starch

Abstract

Effect of debranching for a high-amylose starch (similar to 70% amylose) on its V-complex formation with stearic acid was examined. Gel-permeation chromatograms showed that amylopectin was degraded to smaller molecules as the debranching time increased from 6 to 24 h. Increased formation of debranched starch/stearic acid complexes (recovery yield of stearic acid from 45.17 to 89.31% and starch from 39.92 to 55.43%) was observed with increased debranching time (from 6 to 24 h) and complexation time (from 6 to 24 h). The X-ray diffraction patterns of the debranched starch/stearic acid complexes displayed a mixture of B-type and V-type patterns, with 2. peaks at 7.6 degrees, 13.1 degrees, 17.2 degrees, 20 degrees, 21.6 degrees, and 23.4 degrees. The melting temperature and enthalpy changes of the debranched starch/stearic acid complexes were gradually enhanced with increasing debranching time. These results suggest that starch can be modified by debranching to produce a significant amount of debranched starch/stearic acid complexes.