AMYLOPECTIN - STRUCTURAL, GELATINIZATION AND RETROGRADATION STUDIES

Amaranth, waxy corn, and commercial corn amylopectins were enzymically debranched and their fractions separated by gel filtration. In all ca ses a bimodal distribution of chain lengths was found, containing a hi gh proportion of short chains. Amaranth, waxy corn starches and commer cial corn amylopectin displayed an A-type X-ray diffraction pattern, w hich is characteristic of cereal starches, whereas amaranth amylopecti n did not show a well-defined pattern, suggesting that the former samp les have granular structure. Gelatinisation and retrogradation data, b y differential scanning calorimetry, showed a good agreement between s tarches and amylopectins of the same source. Amaranth starch and its a mylopectin presented a lower tendency to undergo these changes compare d to the remaining tested materials. The temperature effect on retrogr adation was more drastic for amaranth and waxy corn amylopectins.