热诱导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 on Emulsification and Stability of WPC and WPI

比较热聚合乳清浓缩蛋白(PWPC)和热聚合乳清分离蛋白(PWPI)的乳化性和乳化稳定性,分析PWPC和PWPI所带电荷量、微观结构特征以及分子质量分布特征。试验结果表明,PWPC和PWPI与未处理乳清蛋白相比乳化性降低,乳化稳定性升高;85℃的PWPC和PWPI的乳化性和乳化稳定性显著高于90℃的PWPC和PWPI(P<0.05),10%的PWPC和PWPI的乳化性和乳化稳定性高于8%和12%的;在相同条件下,PWPI的乳化性和乳化稳定性显著高于PWPC(P<0.05);PWPC和PWPI的Zeta-电位显著低于未处理的乳清蛋白(P<0.05),PWPI的Zeta-电位显著低于PWPC(P<0.05)。PWPC和PWPI比未处理的乳清蛋白稳定,在相同条件下PWPI比PWPC更稳定。透射电镜显示PWPI的网络结构比PWPC的紧密。分析PWPC和PWPI的SDS-PAGE电泳图谱,α-乳白蛋白和β-乳球蛋白条带强度降低,确定乳清蛋白发生热聚合。

The study compared the emulsification and emulsion stability of WPC and WPI thermal polymerization（PWPC and PWPI）, and analyzed the amount of electric charge, microstructural features and the molecular weight distribution of PWPC and PWPI. The results showed that compared with untreated whey protein（WPC and WPI）, the emulsification of PWPC and PWPI decreased and emulsion stability of PWPC and PWPI increased. The emulsification and emulsion stability of PWPC and PWPI treated at 85℃ were significantly higher than that at 90 ℃（P〈0.05）. At protein concentration of 10%, the emulsification and emulsion stability of PWPC and PWPI were higher than that at 8% and12%. In the same conditions, the emulsification and emulsion stability of PWPI were significantly higher than that of PWPC（P〈0.05）. The zeta-potential of PWPC and PWPI were significantly lower than the untreated whey protein（P〈0.05）. In the same conditions, the zeta-potential of PWPI was significantly lower than that of PWPC（P〈0.05）. The research found that PWPC and PWPI were more stable than the untreated whey protein, and PWPI was more stable than PWPC in the same conditions. TEM showed the network structure of PWPI was more compact than that of PWPC. By analyzing the SDS-PAGE electrophoretic patterns of PWPC and PWPI, it was found that the band intensity of α-lactalbumin and β-lactoglobulin reduced, suggesting that whey protein was thermally polymerized.