基于内源性磷脂-乳清分离蛋白交互作用的磷虾油乳液稳定性研究

The Stability of Krill Oil Emulsion Based on Interaction of Endogenous Phospholipids with Whey Protein Isolate

构建具有较高物理稳定性的乳液体系对最大限度提高磷虾油生物利用率和拓宽其在健康食品中的应用尤为重要。基于此,本文研究了内源性磷脂-乳清分离蛋白(WPI)交互作用对磷虾油乳液理化特性、微观结构和物理稳定性的影响规律和作用机理。结果表明,当载油量为25%时,磷虾油乳液平均粒径和Zeta电位值分别为35.03 nm和-27.3 mV,乳液趋于不稳定。添加0.5%(w/v)WPI使磷虾油乳液的平均粒径和Zeta电位绝对值分别增加84.0%、31.4%(P<0.05),低剪切速率下表观粘度值增加7倍(P<0.05),稳定性指数(TSI)值降低70.3%(P<0.05),乳液趋于稳定。进一步结果显示,内源性磷脂能够与WPI交互作用改善其界面活性,并使WPI中α-螺旋结构含量降低1.60%(P<0.05),内源性荧光强度和表面疏水特性明显增强。环境胁迫稳定性结果表明,模拟巴氏杀菌热处理能够增加磷虾油乳液物理稳定性,且向弱碱性pH迁移过程中(pH6~9)表现出较强的物理稳定性。因此,内源性磷脂-WPI交互作用对构建高物理稳定性磷虾油乳液和拓宽其在健康食品体系中的应用提供了可能。

The construction of emulsion system with high physical stability is pivotal to effectively increase the bioavailability of krill oil and broaden its application in health food. This study aimed to investigate the effects and potential mechanism of the interaction between endogenous phospholipids and whey protein isolate(WPI) on the physicochemical properties, microstructure and physical stability of krill oil emulsion. The results showed that when the oil load increased to 25%, the average particle size and zeta potential value of krill oil emulsion reached 35.03 nm and -27.3 mV, respectively,emulsion tended to be more unstable. The addition of WPI 0.5%(w/v) increased the average particle size and Zeta potential value of krill oil emulsion by 84.0% and 31.40%(P<0.05), respectively. Meanwhile, the apparent viscosity values at low shear rate of krill oil emulsion increased by 7-folds(P<0.05), and the turbiscan stability index(TSI) value decreased by70.3%(P<0.05), thereby leading to stable emulsion. Further results showed that endogenous phospholipids could interact with WPI to improve its interfacial activity, reduce α-helix content in WPI by 1.60%(P<0.05) and evidently enhance its endogenous fluorescence intensity and surface hydrophobicity. The environmental stress stability demonstrated that the simulated pasteurization heat treatment improved the physical stability of krill oil emulsion. In addition, the krill oil emulsion exhibited relatively strong stability when the pH values migrated toward weak alkaline(pH6~9). Therefore, the interaction of endogenous phospholipids and WPI would provide the possibility to construct krill oil emulsion with high physical stability and broadened its application in health food.