Gelatinization, Retrogradation and Disintegration of Starch during the Process of Making Glutinous Rice Cake

Abstract

he degree of gelatinization, retrogradation and disintegration of starch in steamed glutinous rice, fresh glutinous rice cake dough, cooled glutinous rice cake dough and dried cut glutinous rice cake dough prepared under different conditions were estimated by their disperibility in a 0.04% SDS solusion. (1) The degree of gelatinization of starch in steamed glutinous rice increased with increasing moisture content of soaked glutinous rice and steaming time, and was the highest when steamed at 0.2kg/cmcm² steam pressure. (2) The degree of disintegration of starch granules in fresh glutinous rice cake dough prepared with a pounding type machine, a mixing type machine and a kneading type machine were 76.8%, 84.3% and 83.0%, respectively. (3) The degree of gelatinization of starch in the glutinous rice cake dough cooled at 5°C decreased rapidly in a day, and lowered gradually after that. No difference in the degree of gelatinization of starch in the glutinous rice cake dough could be found when cooled at 5-30°C for 24h. However, the degree of retrogradation in strongly bonding micelles of starch in those samples increased with increasing temperature above 10°C between 10 and 30°C. (4) When dried cut glutinous rice cake dough with 20-35% moisture content was placed at 30°C for 24h, the degree of gelatinization of starch in the samples with 30% and 35% moisture contents was a little lower than that with 20% and 25% moisture contents.