The Studies On Extraction And Properties Of Interfacial Proteins From Peanut Emulsion

As a new type of manufacturing technology to extract oil, aqueous has many advantages, such as low energy consumption and excellent product quality. However, a lot of stable emulsion will be produced in the process of manufacture, which seriously affects the yield of the edible oil. The generation of the emulsion severely restricts the industrialized application of the aqueous. This assay aims at studying the emulsion produced in the process of oil extraction by the aqueous. Firstly, the interfacial proteins were extracted from the peanut emulsion and their emulsifying properties were researched. Then, the interfacial proteins were purified by a column of Sepharose CL-6B and RP-HPLC, some fractions were obtained. The emulsifying and structure properties of each fraction were studied.After eluted with water, the optimal condition of oil removal for washed peanut emulsion was obtained by series of single factor experiments: the amount of Tween-20 was 1.5%, stirring time was 60 minutes, and centrifugal force was 20500 g. Under the optimal condition, the oil removal rate was up to 75.21%. The crude extract of the interfacial proteins was obtained after the oil removal. Then, different samples were gotten by dialysis,ammonium sulfate salting out,G15 chromatography and acid precipitation. The purify of the interfacial proteins was the highest, which was up to 64.68% by acid precipitation.Compared with peanut protein isolate, rapeseed protein isolate, and soy protein isolate, peanut interfacial proteins had the lowest solubility, but it showed the highest emulsifying activity, the best emulsion stability and the fastest reducing rate of interfacial tension. DSC thermal characteristics analysis showed that peanut interfacial proteins had been modified.The separation of interfacial proteins by Sepharose CL-6B was optimized. Three major components G1, G2, G3 were collected when the amount of the sample was 300 mg and the flow rate was 40 mL/h. This condition was the optimal. The emulsifying activity and the reducing rate of interfacial tension of G3 were significantly better than G1 and G2. The particle size of emulsifying oil droplets of G3 was the smallest(1.62 μm).The disulfide bond content, surface hydrophobicity of G3 were higher than peanut protein isolate, interfacial proteins, G1, and G2. The disulfide bond content of G3 was 36.24 μmol/g, and surface hydrophobicity was 270.31. The endogenous fluorescence spectroscopies showed that the polar of the microenvironment of G3 was higher than them. The FTIR spectrometer showed that G3 β-sheet structure and random curl structure were more the other four proteins, but the β-angle structure was less than them.G3 was separated by Semi-preparative RP-HPLC, and three major components were obtained, and G3-R3 showed the fastest reducing rate of interfacial tension.