Rice Starch Phase Transition and Detection During Resistant Starch Formation

Rice modification has been a trend for enhancing resistant starch (RS) content to improve rice quality and functionality for health and wellness. Rice grains, rice starch, or ground rice could be treated indigenously, physically, chemically, or enzymatically to develop RS. The level of RS is measured chemically in vitro and in vivo using standard techniques. But these biochemical procedures cannot provide a clear understanding of critical changes in rice grains' physicochemical properties or structural, thermal, and pasting properties during rice processing. Therefore, established analytical techniques like X-ray diffraction analysis (XRD), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) analysis and rapid visco analysis (RVA) could provide valuable details about deformation and phase transition in starch. The changes in rice-starch structure are associated with rice's thermal, morphological, and rheological behavior and cumulatively these parameters could provide a better understanding of starch phase transition during RS formation. Hence, these analytical tools can inform improvising the functional attributes of rice in the form of RS through various treatments. This review focuses on different qualitative and quantitative methods of RS detection, thus supporting the current interest in modifying functional attributes of rice starch.