Study On Extraction Condition And Physicochemical Properties Of Protein In OAT Bran

Oat is a worldwide grown food-feeding combination crops with high nutritional value. China is one of the world’s biggest oats planting countries. However, in the oat manufacturing process, oat bran as by-products is mostly not used, which caused the waste of resources. The purpose of this paper is to optimize the best protein extraction conditions by taking oat bran as raw material, and to research the physicochemical properties of oat bran protein. The results of this paper would provide the basic data and theoretical foundation for the structure research and food industry application of oat bran protein.Respectively studied the extraction technology on the four kinds protein of oat bran(albumin、globulin、gliadin and glutein). The best extraction conditions came out by combing the single factor and orthogonal experiments. The result showed that gluten content is the highest proportion in oat bran protein. The optimum extraction condition of gluten was as follows:0.15% of NaOH, temperature of 50℃, time of 20 min, liquid ratio of 1:8, extract for 4 times. The extraction rate of gluten was 72.88% under the optimal extraction conditions, and the yield wsa 12.15%.Ammonium sulfate precipitation method was used on the purification of protein extracts, the result showed that gluten had a large amount of precipitation when the Ammonium sulfate saturation was 10%, the precipitation was 67.5%. This method had certain purification effect for protein attested by SDS-PAGE polyacrylamide gel electrophoresis, and the purity of protein is 87.22%±0.85%.The physicochemical property of oat bran protein was elucidated by chemical, DSC analysis and atomic force microscope. The result showed that the isoelectric point of oat bran protein was 4.8. Its inherent viscosity was 10.22mL/g, temperature and sucrose adding amount had influence on viscosity. The molecular weight of gluten distributed in wide range from 10KD to 40KD. DSC analysis showed that the denaturation temperature of oat bran gluten is 61.49℃ and the enthalpy is 2.07 J/g. The oat bran gluten appeared flake skeleton structure and had spherical particals on the surface by SEM, and it was further proved by AFM. Besides there was a part of the molecules formed aggregates, and its height was about 19 nm. The liquid-binding power and oil-binding power of oat bran gluten was preferable, and its solubility, foaming ability and emulsification were affected by temperature, pH, salt ion concentration, etc. In different conditions, the foaming ability of oat bran gluten was better than soybean separation protein, but the foam stability was a little poor than soybean separation protein. The emulsification and emulsion stability of oat bran gluten were both better than soybean separation protein. The hygroscopic and moisture resistance of oat bran gluten were poor.