Gel-chromatography fractionation and thermal characterization of rice starch affected by hydrothermal treatment

摘要: Two rice cultivars, high amylose TNS 19 and waxy TCW 70, were selected for a study of thermal behavior molecular redistribution starch after hydrothermal treatments. The treatment conditions included soaking 2 hr at 40°C steaming 10 or 20 min 0 18 psi steam pressure, respectively. Lower temperature endotherms, measured by differential scanning calorimetry, observed 65 72°C the untreated treatments caused shift to higher gelatinization temperatures lower transition enthalpy changes. Simultaneously, endotherm was 115°C only. degradation amylopectin apparently resulted in decreased amount large molecules an increased smaller molecules. heat-moisture-treated flour mixed with water heated then stored 4 25°C. enthalpies concomitant decreases peak during storage. These results indicate that extent retrogradation increases storage time both cultivars. At 4°C storage, 70 from day 7, although 25°C no similar changes throughout 21 days.