乳清分离蛋白-大豆卵磷脂-茶多酚复合物结构表征及其α-亚麻酸乳液递送体系稳定性

Structural Characterization of Whey Protein Isolate-Soy Lecithin-Tea Polyphenols Ternary Complex and Stability of Its Emulsion Delivery System of α-Linolenic Acid

摘要:

为构建高效的α-亚麻酸(α-linolenic acid,ALA)乳液递送体系,以茶多酚(tea polyphenols, TP)、乳清分离蛋白(whey protein isolate, WPI)与大豆卵磷脂(soy lecithin,SL)为原料,通过改变TP添加量(0~1.0mg/mL)制备WPI-SL-TP三元复合物,利用此三元复合物包埋ALA制备乳液递送体系,分析TP质量浓度对复合物结构、功能特性的影响,以及对乳液中ALA包埋效果与稳定性的影响。结果表明,TP通过静态猝灭机制与WPI-SL复合,二者以疏水相互作用为主要驱动力,诱导蛋白质二级结构发生重构。随着TP质量浓度升高,复合物表面疏水性下降,接触角减小,乳化活性增强。这些结构与性质的改变直接影响了乳液性能。TP的添加使ALA包埋率从65%提升至约80%。当TP添加量低于0.6mg/mL时,复合物结构展开不充分,导致乳液液滴聚集,粒径增大,Zeta电位绝对值减小,对ALA的包埋效果不佳；TP添加量达到0.8mg/mL及以上时,复合物因结合了更多TP,产生了更强的静电斥力与空间位阻效应,进而形成粒径更小(411.73nm)、Zeta电位绝对值更高(15.93mV)、分散更均匀的乳液,显著提升了对ALA的包埋效率。稳定性研究结果表明,TP质量浓度为0.8mg/mL时,乳液热稳定性较佳。研究旨在为基于蛋白-磷脂-多酚协同作用的活性脂质高效递送系统设计提供理论依据。

Abstract:

To construct an efficient emulsion delivery system for α-linolenic acid (ALA), tea polyphenols (TP), whey protein isolate (WPI), and soy lecithin (SL) were used as raw materials. The WPI-SL-TP ternary complex was synthesized by varying the mass concentration of TP (0-1.0mg/mL), followed by the encapsulation of ALA to prepare the emulsion dilivery system. The effects of TP mass concentration on the structural and functional properties of the complex, as well as on the encapsulation efficiency and stability of the ALA emulsion were analyzed. The findings indicated that TP combined with WPI-SL through a static quenching mechanism, primarily driven by hydrophobic interactions, which facilitated the reorganization of the protein secondary structure. With the increase of TP mass concentration, the surface hydrophobicity of the complex decreased, leading to a reduction in the contact angle and an enhancement of emulsifying activity. These structural and property changes directly influenced the performance of the emulsion. The addition of TP increased the encapsulation efficiency of ALA from 65% to approximately 80%. When the TP mass concentration was lower than 0.6mg/mL, the complex structure remained inadequately developed, resulting in aggregated emulsion droplet, increased particle size, decreased absolute Zeta potential, and reduced ALA encapsulation efficiency. When the mass concentration of TP reached 0.8mg/mL and above, the complex exhibited enhanced electrostatic repulsion and steric hindrance due to the increased binding of TP. This interaction resulted in the formation of an emulsion characterized by smaller particle size (411.73nm), higher absolute Zeta potential (15.93mV), and more uniform dispersion, thereby significantly improving the encapsulation efficiency of ALA. Stability assessments indicated that the emulsion achieved optimal thermal stability at the TP mass concentration of 0.8mg/mL. This study aimed to provide a theoretical foundation for the design of efficient delivery systems for active lipids, based on the synergistic effects of proteins, phospholipids, and polyphenols.