Purification And Physicochemical Properties Analysis Of Oat β-glucan

Oat β-glucan is one kind of non-starch polysaccharide which is usually concentrated in endosperm and aleurone cell walls of oat. Studies have shown that it has many important physiological functions. In this paper, oat bran was used as raw material, the optimum parameters for purifying oat β-glucan were determined, the other ingredients and physicochemical properties of oat β-glucan were analyzed. The results provide valuable reference for research oat β-glucan.This paper focuses on the purification process of oat β-glucan. The first removed the pectin with pectolase and the protein with centrifuge; and then removed the starch through the thermostable a-amylase; the final obtained oat β-glucan by the second ethanol precipitation process. The influences of pectolase reaction pH, temperature, dosage and reaction time were researched. And the optimum parameters of pectolase reaction were determined by orthogonal test. The optimum dosage and hydrolysis time of thermostable a-amylase were determined under the optimum pH and temperature. Analyze the optimum concentration of ethanol in the second ethanol precipitation process.There are the optimum parameters of purification process. The pH of pectolase reaction was 5.5, temperature was 60℃, dosage was 0.06mg/(5g raw materials) and reaction time was 5min. The optimum dosage of thermostable a-amylase was 15U/(5g raw materials) and the hydrolysis time was 10min. The optimum concentration of ethanol was 80% in the second ethanol precipitation process. The yield of β-glucan obtained by this purification process was 4.18%, the purity was 67.14%.The content of other components in the product were that 10.82% moisture,0.77% ash, 1.68% protein,1.03% fat. The impurity content of products which obtained through this process was less than the products which were sold in market.The molecular weight of oat β-glucan which determined by sepharose CL-4B gel-filtration column chromatography was 5.0×105. The solubility of oat β-glucan was well and stable. It is better than commercial products. Effect of temperature on the solution viscosity of oat β-glucan was significant. With the increasing temperature the viscosity was decreased. Effect of pH on the solution viscosity was little. Effect of temperature and pH on the products taken by this process and commercial products were similar. It was indicated that they may had the same physicochemical properties. Whatever products taken by this process or commercial products, the thermal stability of solution in pH 7.0 was better than pH 4.0. The thermal stability of the products which obtained through this process was better than commercial products.The process was simple, and the products had high purity and solubility. It is benefited for the further development and utilization of oat β-glucan.