ENZYME-RESISTANT STARCH .5. EFFECT OF RETROGRADATION OF WAXY MAIZE STARCH ON ENZYME SUSCEPTIBILITY

Gelatinized waxy maize starch (100% amylopectin) was subjected to different time and temperature conditions of storage to obtain samples with differences in the extent of amylopectin retrogradation. The resulting samples showed melting endotherms with varying onset, peak, and completion temperatures, as well as varying melting enthalpies. X-ray diffraction also showed variance in the degree of crystallinity. Increased retrogradation extents (higher melting temperatures, melting enthalpies, and higher crystallinity levels) caused reduced enzyme susceptibilities to pancreatic alpha-amylase and amyloglucosidase at 37-degrees-C.