微观结构和光散射结果表明乳清分离蛋白比大豆分离蛋白具有更好的乳化性能，利用乳清分离蛋白可以制得粒径更小和分布更加均匀的油相。粘度测定结果表明相比于大豆分离蛋白，乳清分离蛋白与海藻酸钠之间具有更强的化学交联，从而导致含有乳清分离蛋白的海藻酸钠乳液凝胶珠具有更强的杨氏模量。相比于空白组，在体外模拟胃消化过程中含有乳清分离蛋白或大豆分离蛋白的海藻酸钠乳液凝胶珠具有更显着的杨氏模量增加和脱水收缩作用从而延缓了番茄红素在体外模拟肠消化过程中的释放。本研究的结果对利用天然大分子物质来对乳液凝胶进行结构改造从而达到对包埋物质的消化控释具有重要指导意义。
Abstract
Effect of structuring emulsion gels by whey or soy protein isolate on the structure, mechanical properties, and in-vitro digestion of alginate-based emulsion gel beads
Duanquan Linab, Alan L. Kellyb, Valentyn Maidannyka, Song Miaoab
Whey protein isolate (WPI) and soy protein isolate (SPI) were used as emulsifiers and structure-modifying agents to produce alginate-based emulsion gel beads. The purpose of this study was to compare the effects of WPI and SPI on the structural and mechanical properties of alginate-based emulsion gel beads and the in-vitro release of encapsulated lycopene from emulsion gel beads. The results of microscopy and light scattering indicated that WPI had better emulsifying properties than SPI, resulting in emulsions with smaller and more even droplet size distribution. The rheological properties of protein/alginate mixtures and emulsions indicated strong interactions between WPI and alginate and weak interactions between SPI and alginate, resulting in increased Young's modulus of WPI-stabilized emulsion gel beads and decreased Young's modulus of SPI-stabilized emulsion gel beads, compared to gel beads without proteins. The presence of WPI and SPI increased changes of Young's modulus and shrinkage during simulated gastric digestion and delayed the release of lycopene from gel beads. Findings in this study are important for structuring emulsion gels with naturally occurring polymers to achieve controlled release of encapsulated compounds.
