Effects of Cross-linking of Rice Protein with Ferulic Acid on Digestion and Absorption of Ferulic Acid

Though rice proteins have been applied to improve the stability of phenolic compounds, the effects of rice proteins on the digestibility and bioavailability of phenolic acid have not been clear. This study devoted to understanding the effects of protein interaction with ferulic acid on the digestion and absorption of ferulic acid in gastrointestinal environment. Ferulic acid were formed complexes with rice proteins with and without the presence of laccase at room temperature. It was found that rice protein could protect ferulic acid from degradation in simulated oral fluid and remain stable in gastrointestinal fluids. With the hydrolysis of pepsin and pancreatin, rice protein-ferulic acid complexes degraded and released ferulic acid in gastrointestinal environment. The DPPH scavenging activity digested rice protein-ferulic acid complexed was maintained while that of digested ferulic acid was significantly decreased. Moreover, the permeability coefficient of ferulic acid was not affected by rice peptides. Thus, rice protein is a promising food matrix to protect ferulic acid in digestion tract and maintain the antioxidant functions of ferulic acid.