Sustainable techniques to enhance novel techno-functional properties and modulate starch digestibility of polyphenol-rich red rice flours with varying amylose content

Abstract

Red rice flours performed modification using sustainable techniques, including ANN (annealing), HMT (heat moisture treatment), US (ultrasound), Pregel (Pregelatinization), WM (wet-microwave treatment), and DM (dry-microwave treatment). Manpo rice flour, which is high in amylose, demonstrated higher peak viscosity compared to flours from medium-high amylose rice (Hommali rice), under the same treatment conditions. The reduction in swelling power observed after ANN and HMT treatment in both varieties corresponds with the pasting behaviors of these flours. All samples exhibited notable shear-thinning properties. Pregel samples exhibited rapid digestion, with the maximum RDS levels reaching 35.4 % for Manpo rice and 37.3 % for Hommali rice. While, the structure of US samples changed, resulting in enhanced polyphenol bioaccessibility and decreased digestion rate. The lowest eGI recorded in US samples was 60.7 for Manpo rice and 61.5 for Hommali rice, with polyphenol bioaccessibility at 180 min measured at 37 % and 28.8 %, respectively. This study documents the impact of sustainable practices on the properties of red rice flours, thereby enhancing its culinary applications for future commercialization.