College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, People's Republic of China.
College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, People's Republic of China.
Int J Biol Macromol. 2018 Oct 15;118(Pt B):2208-2215. doi: 10.1016/j.ijbiomac.2018.07.086. Epub 2018 Jul 20.
ε‑Polylysine (ε-PL) is a new natural food-grade antimicrobial that has been widely applied in the food and beverage industry. This study characterized the physicochemical properties of an electrostatic complex of the ε-PL and whey protein at different whey protein-to-ε-PL mass ratios, pH, and ionic strength by using the turbidity measurements, size and zeta potential measurements. The interaction and formation mechanism of the electrostatic complexes are explored by analysis of the hydrogen bonds and ion pairs, hydrophobic and hydrophilic solvent assessable surface area and secondary structure using molecular dynamics simulations. The experimental results showed that the ε-PL bound to the surface of whey protein forming an electrostatic complex which could be either soluble or insoluble depending on the whey protein-to-ε-PL mass ratios, pH, and ionic strength. The molecular dynamics simulations results showed that conformational rearrangements of α‑lactalbumin and bridging effect of β‑lactoglobulin occurred. The interaction was mostly driven by the hydrogen bonds and ion pairs, which mainly occurred in the hydrophilic part of the whey protein surface. This study provides the theoretical basis that will facilitate more rational application of ε-PL in the food matrix.
ε-聚赖氨酸（ε-PL）是一种新型的天然食品级抗菌剂，已广泛应用于食品和饮料行业。本研究通过浊度测量、粒径和 Zeta 电位测量，表征了不同乳清蛋白与ε-PL 质量比、pH 值和离子强度下ε-PL 与乳清蛋白静电复合物的理化性质。通过分子动力学模拟分析氢键和离子对、疏水性和亲水性溶剂可及表面积以及二级结构，探讨了静电复合物的相互作用和形成机制。实验结果表明，ε-PL 结合到乳清蛋白表面形成静电复合物，其溶解度取决于乳清蛋白与ε-PL 的质量比、pH 值和离子强度。分子动力学模拟结果表明，α-乳白蛋白发生构象重排，β-乳球蛋白发生桥接效应。相互作用主要由氢键和离子对驱动，主要发生在乳清蛋白表面的亲水部分。本研究为在食品基质中更合理地应用ε-PL 提供了理论依据。
