高压微射流处理对大豆分离蛋白结构功能特性及其乳液性质的影响

Effects of high-pressure microfluidization on structure,functional and emulsion properties of soy protein isolate

采用高压微射流技术在不同压力条件下对大豆分离蛋白(SPI)进行处理,分析处理前后SPI结构、功能特性以及乳液性质的变化。结果表明:低压均质处理可使SPI的粒径降低,当均质压力增加至一定程度时,蛋白间的相互作用增加,颗粒粒径增加;均质压力在0~95 MPa范围内随着压力逐渐升高,SPI的溶解性得到了显著改善,而当均质压力增加到125 MPa和155 MPa时,溶解性反而降低;高压均质处理对乳化性的影响与溶解性变化趋势基本吻合;表面疏水性随着压力的增大而增大;内源荧光光谱结果表明,随着均质压力的增大,最大吸收波长红移,荧光强度降低,色氨酸残基暴露于极性环境中;SPI乳液粒径随着均质压力的增大(95 MPa除外)整体依次变小,SPI乳液在压力65 MPa处理时油脂氧化速率最快,SPI乳液在压力125、155 MPa处理时的初级氧化速率要低于未处理的乳液。

The soy protein isolate( SPI) was treated under different pressures by dynamic high-pressure microfluidization( DHPM) technology. The changes of structure,functional and emulsion properties of SPI before and after DHPM treatment were analyzed. The results showed that the low-pressure homogenization treatment could reduce the particle size of SPI. When the homogenization pressure increased to a certain extent,the interaction between proteins increased,and the particle size with the same trends.With the homogenization pressure gradually increased from 0 MPa to 95 MPa,the solubility of SPI was significantly improved. However,when the homogenization pressure increased to 125 MPa and 155 MPa,the solubility decreased. The effect of high-pressure treatment on emulsifying ability was basically consistent with the change trends of solubility. The surface hydrophobicity increased with the increase of pressure. The endogenous fluorescence results showed that with the increase of homogenization pressure,the maximum absorption wavelength red shifted,the fluorescence intensity decreased,and the tryptophan residue were exposed to the polar environment. The particle size of SPI emulsion decreased with the increase of homogeneous pressure except 95 MPa. The oxidation rates of the emulsion was the fastest when the pressure was 65 MPa,and the primary oxidation rates of the emulsion at 125 MPa and 155 MPa were lower than that of the untreated emulsion.