College of Food Science and Engineering , Ocean University of China , Qingdao 266001 , People's Republic of China.
College of Food Science and Engineering , Qingdao Agricultural University , Qingdao 266109 , People's Republic of China.
J Agric Food Chem. 2019 Sep 18;67(37):10412-10422. doi: 10.1021/acs.jafc.9b03046. Epub 2019 Sep 10.
In this study, aggregation of fucoxanthin (FX) and its effects on binding and delivery properties of whey proteins were explored. Initially, the H- and J-aggregates of FX were successfully prepared by adjusting the water/ethanol ratio and water-dripping rate. The transition from J- to H-aggregates was observed over the standing time. Then, the molecular arrangement of FX H-aggregates was analyzed using the point-dipole approximation model and molecular dynamics, showing that their intermolecular distance and angle were about 5.0-6.7 Å and -35° to 35°, respectively. The transformation of J- to H-aggregates was also observed during molecular dynamics, with a shortened intermolecular distance, a reduced solvent accessible surface area, an enhanced interaction force, and a narrowed dihedral angle. Further, the interactions of whey proteins with different forms of FX were investigated, indicating that both β-lactoglobulin and whey protein isolates could form complexes with the monomers, H-aggregates, and J-aggregates of FX. In terms of affinity, whey proteins bound FX monomers more strongly than aggregates. Furthermore, the complexes comprising whey proteins and monomeric FX had better delivery capabilities than aggregated FX, manifested in encapsulation efficiency, physical stability, and bioaccessibility.
在这项研究中，探讨了岩藻黄质（FX）的聚集及其对乳清蛋白结合和递送特性的影响。首先，通过调整水/乙醇比和滴水速率成功制备了 FX 的 H-和 J-聚集物。在静置时间内观察到 J-到 H-聚集物的转变。然后，使用点偶极近似模型和分子动力学分析了 FX H-聚集物的分子排列，结果表明它们的分子间距离和角度分别约为 5.0-6.7 Å 和 -35°至 35°。在分子动力学过程中也观察到 J-到 H-聚集物的转变，表现为分子间距离缩短、溶剂可及表面积减小、相互作用力增强和二面角变窄。此外，还研究了乳清蛋白与 FX 不同形式的相互作用，表明β-乳球蛋白和乳清蛋白分离物均可与 FX 的单体、H-聚集物和 J-聚集物形成复合物。就亲和力而言，乳清蛋白与 FX 单体的结合比聚集物更强。此外，包含乳清蛋白和单体 FX 的复合物比聚集态 FX 具有更好的递送能力，表现在包封效率、物理稳定性和生物可及性方面。
