高压均质对天然和热变性大豆蛋白-磷脂水包油型乳状液功能性质的影响

Functional Properties of Natural and Denatured Soybean-Lecithin Oil-in-Water Emulsions Treated by High Pressure Homogenization

为揭示大豆蛋白和大豆卵磷脂在油-水界面层的交互作用及复合微乳体系的稳定机制,探究了温度(20、60℃)和均质压力(0~80 MPa)的协同作用对蛋白质-磷脂复合乳化体系功能性质的影响。结果显示:相比于天然大豆蛋白与磷脂(native soybean isolate-lecithin,NSI-Lec)形成的乳状液,热变性大豆蛋白与磷脂(denatured soybean isolate-lecithin,DSI-Lec)的乳状液功能性质随均质压力的变化更明显。NSI-Lec乳液在均质压力达到80 MPa时乳化性、乳化稳定性及电位变化不再显著,但DSI-Lec乳液在该条件下功能性质继续提高。当均质压力高于40 MPa时,DSI-Lec乳液的乳层析指数明显下降,说明乳液更加稳定。粒径分布结果表明:NSI-Lec乳液呈双峰粒径分布,DSI-Lec乳液在均质压力高于20 MPa后粒度分布曲线向小粒径方向移动,且当均质压力达到80 MPa时粒径分布呈现单峰。激光共聚焦显微镜结果显示,DSI-Lec乳液随均质压力的提升分布更均匀,乳液连续性较好。

The purpose of this study was to explore the effect of homogenization pressure and heat treatment on functional properties of soybean protein-lecithin emulsion system to further reveal the soybean protein-lecithin interaction at the oilwater interface and the stability mechanism of the emulsion system. The results showed that compared to native soybean isolate-lecithin (NSI-Lec) emulsion, functional properties of denatured soybean isolate-lecithin (DSI-Lec) emulsion changedmore obviously as homogenization pressure increased. The emulsibility, emulsion stability and zeta potential value ofNSI-Lec emulsion did not change significantly any more when homogenization pressure reached 80 MPa. But functionalproperties of DSI-Lec emulsion were still improved under this condition. Creaming index of DSI-Lec emulsion decreasedwhen homogenization pressure was higher than 40 MPa, which indicated the emulsion to be stable. NSI-Lec emulsionshowed bimodal particle size distributions, while DSI-Lec emulsion distribution curves showed a slight shift toward smallerdroplet sizes when homogenization pressure was 20 MPa. Unimodal particle size distribution was found when pressure increased up to 80 MPa. Confocal laser scanning microscopy revealed that DSI-Lec emulsion had a well-distributed pattern and continuity along with increasing homogenization pressure.