Abstract
Differential scanning calorimetry (DSC) was used to estimate the intracellular water content during the gelatinization of starches inside cotyledon cells prepared from adzuki, faba and kidney beans. DSC thermograms and their characteristics of cotyledon cells in excess water were compared with those of isolated starches in various water contents. DSC thermograms of cotyledon cells in excess water (85-88%) showed an endothermic transition with a peak temperature, which trailed a shoulder or another peak at higher temperatures. The melting temperature of cotyledon cells in excess water were 95.7, 94.5 and 96.9t for adzuki, faba and kidney beans, respectively. The water content of isolated starches which showed the same melting temperature as the cotyledon cells in excess water were 56, 58 and 61% for adzuki, faba and kidney beans, respectively. The gelatinization enthalpies of cotyledon cells and the proportion of higher-temperature peak in thermograms in excess water were identical with those of isolated starches at water contents of 56-58%. From these results, the intracellular water content during the gelatinization of starches inside cotyledon cells of legumes in excess water were estimated to be 56-61%.
