Extraction and Characterization of Rice Bran Polysaccharides and Their Derivative Preparation and Antioxidant Activity

Abstract

The crude polysaccharide of rice bran polysaccharide was extracted with water from defatted rice bran, and the optimal reaction conditions of the experiment were determined. The reaction temperature is 100{degrees}C, the reaction time is 5h, the solid-liquid ratio is 1:10; the concentration ratio of polysaccharide to Sevag reagent is 2:1, and rice polysaccharide is precipitated by ethanol insoluble property and ethanol. The ethanol concentration ratio is 3:1. Using the methods and conditions of this experiment, the maximum polysaccharide yield is 2.18%. Then the chemical structure of rice bran polysaccharide was analyzed by IR, UV and 13CNMR methods. Three rice bran polysaccharide derivatives were prepared and characterized: carboxymethylated rice bran polysaccharide, phosphorylated rice bran polysaccharide and acetylated rice bran polysaccharide. Also studied the antioxidant activity of rice bran polysaccharide and its derivatives (hydroxy radical ion scavenging ability, superoxide anion scavenging ability, anti-lipid peroxidation ability, reducing ability), and found that phosphorylated rice bran polysaccharide has good activity. The acetylated rice bran polysaccharide may weaken the original activity.