Thermal and Enzymatic Treatment of Rice Starch from Underutilized Cultivars to Improve Resistant Starch III for Sustainability and Future Foods: Physicochemical, Morphological, and Thermal Characteristics

This study investigated the efficacy of a combined thermal and pullulanase treatment to improve resistant starch (RS) III from six traditional rice cultivars. These treatments significantly influenced the physical, morphological, and thermal characteristics, improving RS III in thermal and pullulanase-treated rice starch samples. The RS content ranged from 15.46 to 19.22 g/100 g, with varying amylose from 28.12% to 32.28%. X-ray diffraction analysis revealed a transition in crystallinity from A-type to a combination of B-type and V-type, attributed to retrogradation processes. Differential scanning calorimetry analysis indicated an augmented gelatinization enthalpy change with increasing RS concentrations. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy confirmed structural alterations induced by the treatments. Microscopic observations illustrated surface disturbances, folds, and ruptures on the starch granules. These collective findings highlight the effectiveness of thermal and pullulanase treatments in enhancing RS III, thus expanding its potential for sustainable food production and innovative future food developments.