海藻糖和蔗糖对纳米乳液冻融稳定性的影响

实验研究了2种双糖(蔗糖和海藻糖)对乳清分离蛋白纳米乳液冻融稳定性的影响。蔗糖是一种常用的乳液冷冻保护剂。为对比海藻糖与蔗糖保护效果的差异,采用激光粒度仪、Zeta-电位和Turbiscan Lab稳定分析仪,依次测定冻融循环过程中液滴粒径分布、表面电荷变化和乳液的稳定性。从外观图和乳析指数结果看,经过1~3次冻融处理后,添加蔗糖和海藻糖的实验组乳液无明显分层现象,而无添加的空白样品出现明显分层,表明双糖的加入有助于增强纳米乳液的冻融稳定性。粒径结果显示,4%~5%的海藻糖能有效抑制冻融引发的乳液粒径增长。Turbiscan背散射光曲线表明添加10%蔗糖和5%海藻糖的乳液经冻融后基本能维持均一。并且海藻糖可以在较低添加浓度下使蛋白质稳定的纳米乳液在冻融过程中保持稳定、抑制乳液粒径增长,其效果优于蔗糖,有潜力成为新型乳液冷冻保护剂。

Effect of Trehalose and Sucrose on the Freeze-Thaw Stability of Nanoemulsion

The effect of adding sucrose and trehalose on the freeze-thaw stability of whey protein isolate (WPI)-stabilized nanoemulsion was studied.Sucrose is one of the commonly used protective agents for emulsions in the freeze-thaw process.The experiment tried to compare the protective effect of sucrose and trehalose.Here,the dynamic light scattering,zeta-potential analysis,and the Turbiscan Lab analyzer were combined to study the freeze-thaw stability of the emulsions when adding the sucrose and trehalose.The changes in the appearance and creaming index of WPI-stabilized nanoemulsions showed that addition of sucrose and trehalose had no obvious separated layer after 3 cycles of freezing-thawing.But the control emulsions without adding any sugar displayed two layers after freezing and thawing.The results indicated that adding sucrose and trehalose could improve the freeze-thaw stability of WPI-stabilized emulsions.Besides,the addition of 4%~5% trehalose inhibited the growth of emulsion droplets size after the freezing-thawing.The results of Turbiscan revealed that emulsions with 10% sucrose and 5% trehalose kept uniform.What’s more,trehalose can protect the WPI-stabilized nanoemulsion against the disability of freeze-thaw at a lower concentration.The protective effect of trehalose was better than that of sucrose,and it has a potential application in the protection of emulsions in the frozen food.