Insight into the nutritional, physicochemical, functional, antioxidative properties and in vitro gastrointestinal digestibility of selected Thai rice: Comparative and multivariate studies

Abstract

Nutritional, physicochemical, functional, antioxidative and digestion properties of brown and white rice flours from four Thai rice varieties (Luangpatue, upland rice, RD43, and Hommali) were investigated and compared. Due to differences in grain color, the color parameters of flours varied significantly. Protein, fat, ash, carbohydrate, and moisture content, total dietary fiber, and calories of these rice flours were 6.94-10.21%, 1.68-3.16%. 0.554-1.442%, 71.20-79.68%, 9.79-10.53%, 1.07-3.64%, and 350.82-362.73 kcal/100g, respectively. RD43 brown rice (18.4%) and Luangpatue white rice (26.5%) respectively exhibited the lowest and highest amylose content. Luangpatue rice flours also showed higher swelling power, setback value, final viscosity, and thermal properties than other varieties. The variations in hydration properties and oil absorption index were noticeable among these rice flours. In addition, the highest level of total phenolic content and antioxidant activity led to the lowest estimated glycemic index (eGI = 62.92) found in upland brown rice. It was confirmed by the multivariate analysis results. This study reported the diverse physicochemical properties and composition-property relationships of two kinds of flours from four rice varieties collected from Thailand for the first time. It exhibited possible capabilities for the development of various rice-based products that promote health based on their characteristics on industrial scale.