Dietary polyphenols are abundant antioxidants in the human diet and are associated with lower rates of diabetes and cardiovascular disease. This study aims to determine the effects of cooking white rice (WR) added with lingonberry (WRLB), cranberry (WRCB), and red grape (WRRG) on in vitro digestibility. There was significantly lower level of glucose release for WRRG compared with WR (p < 0.05). WRLB and WRCB showed no effect on glucose release compared with WR (p > 0.05). Increasing concentrations of red grape polyphenol decreased digestibility of white rice (p < 0.05). A positive correlation between the red grape phenolic content and the resistant starch was observed (R = 0.9854). Red grape polyphenol had the greatest impact on reducing in vitro digestibility of white rice. The addition of polyphenols in carbohydrate-rich foods may be a practical means to reduce the high glycemic response of rice eaten around the world.
Keywords: Cranberry; digestibility; lingonberry; polyphenol; red grape; rice; type 2 diabetes.