热处理时间对乳清浓缩蛋白和分离蛋白乳化性及稳定性的影响

Effect of heat treatment time on emulsification and stability of WPC and WPI

以乳清浓缩蛋白(WPC)和分离蛋白(WPI)为研究对象。研究不同热处理时间对热聚合乳清浓缩蛋白(PWPC)和热聚合乳清分离蛋白(PWPI)的游离巯基、Zeta-电势、黏度、粒径、內源性色氨酸荧光光谱、乳化性和乳化稳定性的影响。结果表明,PWPC和PWPI的游离巯基含量均显著降低(P<0.05),且PWPI的游离巯基含量显著高于PWPC(P<0.05);PWPC和PWPI的乳化性均显著降低(P<0.05),而乳化稳定性却显著提高(P<0.05),在热处理时间范围内,PWPC和PWPI的游离巯基含量和Zeta-电位均呈先下降后上升趋势,黏度呈上升趋势,而内源荧光色氨酸光谱、乳化性和乳化稳定性呈先上升后下降趋势。

The effects of heat treatment time （15, 30, 45, 60 90 rain） on the thermal polymerization of whey protein concentrate （PWPC） from whey protein concentrate （WPC） and thermal polymerization of whey protein isolate （PWPI） from whey protein concentrate （WPC） were studied. The free sulfhydryl groups, Zeta potential, viscosity, particle size, intrinsic tryptophan fluorescence spectra, emulsification and emulsion stability were determined. The test results showed that the contents of free sulfhydryl group PWPC and PWPI were significantly decreased （P〈0.05）, however the free sulfhydryl groups content of PWPI was significantly higher than that of PWPC （P〈0.05）. The emulsion of PWPC and PWPI were significantly decreased （P〈0.05）, while the emulsion stability is significantly improved （P〈0.05） within 90 rain of heat treatment. The contents of free sulfhydryl groups Zeta- potentials of PWPC and PWPI were decreased first and then increased, however the viscosity increased within 90 min of heat treatment. The fluorescence spectra of tryptophan, emulsification and emulsion stability were increased at first and then decreased within 90 min of heat treatment.