Fermented red rice improved the antioxidant activity, bioaccessibility of polyphenols, and lipid-lowering activity in C. elegans

Red rice is a kind of whole grain with health benefits. Probiotic fermentation is widely applied to promote nutrient release from cereals and improve bioactivity. The study aims to investigate the impact of Lactiplantibacillus plantarum (L. plantarum) dy-1 fermentation on the bioactivities, bioaccessibility, and lipid-lowering activities of red rice. Results indicated that fermentation significantly increased the protein and total phenolic content by 1.7 and 1.4 times of red rice, as well as the content of essential and nonessential amino acids. Fermentation remarkably increased the bioaccessibility of phenolics and the antioxidant capacity of red rice during in vitro digestion. Additionally, Caenorhabditis elegans study revealed that fermented red rice extract reduced the triglyceride content, alleviated fat deposition, and regulated lipid metabolism by altering the genes in the fatty acid oxidation and synthesis, such as daf-16, mdt-15, nhr-49, fat-5, fat-7, and hosl-1. Therefore, L. plantarum dy-1 fermentation was beneficial for improving bioaccessibility and lipid-lowering activities of red rice, which will provide a reference for utilization of red rice as a functional food.