射流空化对大豆分离蛋白-磷脂酰胆碱乳化特性的影响

Effect of Jet Cavitation on Soy Protein Isolate-Phosphatidylcholine Emulsion Properties

为探究射流空化对大豆分离蛋白(soy protein isolates,SPI)-磷脂酰胆碱(phosphatidylcholine,PC)复合体系乳化特性影响,采用荧光光谱表征复合体系构象变化,并分析乳层析指数、粒径、微观结构、表面疏水性和乳化活性及乳化稳定性解析射流空化对SPI-PC复合乳液结构变化及理化/功能性质的影响。结果表明:射流空化能显著改善复合乳液理化性质及乳化性等功能特性,与SPI相比,0.2 MPa、10 min处理组SPI-PC复合乳液的乳化活性指数和乳化稳定性指数分别增加了82.7%和9.43倍。通过动态光散射和光学显微镜验证了射流空化处理SPI-PC较未射流空化处理样品的平均粒径减小,且表面疏水性提高,其中空化压力0.2 MPa、空化时间10 min时,复合乳液的平均粒径最低,表面疏水性最高;说明射流空化处理会使SPI疏水基团暴露,使SPI与PC之间的相互作用增加。荧光光谱分析说明空化作用力对SPI产生了猝灭作用。

This study was undertaken in order to investigate the effect of jet cavitation on physicochemical and functional properties of a soy protein isolate(SPI)-phosphatidylcholine(PC)stabilized emulsion.The conformational changes of the composite system were characterized by fluorescence spectroscopy,and the creaming index,particle size,microstructure,surface hydrophobicity and emulsifying activity and emulsion stability were analyzed.The results showed that jet cavitation significantly improved physicochemical and emulsifying properties of the composite emulsion.The emulsifying activity index(EAI)and emulsion stability index(ESI)of the composite emulsion treated at 0.2 MPa for 10 min were 82.7%and 10.43-fold higher than those of the single SPI stabilized emulsion,respectively.The average particle size of the composite emulsion system became smaller and surface hydrophobicity became higher after jet cavitation as examined by dynamic light scattering and optical microscopy.The lowest average particle size and the highest surface hydrophobicity were obtained with the 0.2 MPa/10 min treatment.Thus,we concluded that jet cavitation could cause the exposure of hydrophobic groups in the interior of the protein,increasing the interaction between the protein and PC.Fluorescence spectroscopy indicated that cavitation force had a quenching effect on the fluorescence intensity of SPI.