Modified flour of pigmented rice and its structure-activity relationship after hydrothermal pre-treatments: Validation through physicochemical, structural, molecular modelling and simulation insights

Abstract

Pigmented rices are one of the key staple foods to reverse the type II diabetes. Mappillai samba (MS), pigmented and White Ponni (WP), are mostly used rices in South India. This study focused on antidiabetic activity of modified flours of MS and WP rice upon hydrothermal pretreatments: brown (B), unpolished (UP), and parboiled polished (PP). Modified rice flour exhibited gradual amplification of releasing adequate sugar, starch and amylose. They showed 90.81–80.92 % inhibition in MS than WP's (66.25–49.90 %) against α-amylase, whereas α-glucosidase was high inhibition (88.20–73.30 %) compared to White (40 %). SEM, FTIR, XRD and DSC profiles of modified red and white rice flours provided the essential evidences and correlation for the changes in functional groups, polymerizing degree and thermo-diffraction resulted in metabolite-antidiabetic relationship. Eleven compounds of MS were taken for in silico validation opposing α-amylase and α-glucosidase. Molecular docking of MS rice flour revealed that stigmasterol and cycloartenol displayed highest docking scores of −9.9 and −9.7 kcal/mol, found most effective against diabetic targets. 3D docking pose and 2D plots deliver evidence for MS flour's low glycemic index. This study suggests that consumption of pigmented rice helps to control the blood sugar levels in people with type II diabetes.