Preparation, Purification, Characterization and Antioxidant Activity of Rice Bran Fermentation Broth with Hypsizigus marmoreus

The main purpose of this study was to investigate the composition, characterization and antioxidant activity of rice bran fermentation broth, and provide a new way for high-value utilization of rice bran. Firstly, we fermented rice bran with Hypsizigus marmoreus and purified fermentation broth with macroporous resins. We took feruloyl oligosaccharides (FOs) concentration as the measure index, and the results showed that the maximum concentration of FOs was 0.72 mmol/L on the 6th day of rice bran fermentation. We took D101 macroporous resin as adsorption resin for rice bran fermentation broth, and the result showed that FOs concentration reached 2.38 mmol/L with the optimal purification process at pH 4.5, temperature 29 °C, ethanol concentration 55%, sample flow rate 1.5 mL/min, sample concentration 1.7 mL/min and elution flow rate 2.0 mmol/L. Secondly, the characters of rice bran fermentation broth were identified by high-performance liquid chromatography (HPLC) and Fourier-transform infrared spectroscopy (FTIR). These methods showed the presence of ferulic acid (FA), arabinose, xylose and glucose in rice bran fermentation broth. Finally, the in vitro antioxidant activities of rice bran fermentation broth were tested and the result showed that fermentation broth had good antioxidant activities and significantly improved after purification.