高冻融稳定性蛋白颗粒稳定皮克林乳液的形成途径、机理及应用

Freeze-thaw stability of food emulsions is an important item affecting the quality of frozen foods and sauces (e.g. mayonnaise). Many strategies has been performed to improve the freeze-thaw stability of emulsions. The applicant and his research recently found that Pickering emulsions stabilized by food nanoparticles exhibited an excellent freeze-thaw stability, which may provide an effective strategy to improve the freeze-thaw stability of emulsions. The objective of the work was to improve the freeze-thaw stability of Pickering emulsions stabilized by protein particles, by means of formation of a gel-like network, and unravel the undering mechanism for the improved stability. First, the fabrication and emulsification properties of protein-based Pickering stabilizers were investigated, with the aim to produce the stabilizers with good freeze-thaw stability. Then, the physicochemical, microstructural and rheological properties, as well as the freeze-thaw stability of the corresponding Pickering emulsions were characterized. The relationships between the microstructure or rheological behavior and freeze-thaw stability were established. Next, the improvement of the freeze-thaw stability of Pickering emulsions by means of formation of a gel-like network was studied. Last, the feasibility to develop sauces or other emulsion-based products with high freeze-thaw stability, through substituting or partially substituting egg yolk with protein nanoparticles was testified. The findings would be of great importance not only for enriching the knowledge about the freeze-thaw stability of emulsions, but also for providing an effective technical strategy to develop high quality sauces or other emulsion-based products.

提高食品乳液的冻融稳定性是当今冷冻食品、酱制品（如蛋黄酱）领域亟待解决的关键科技问题。申请人及研究小组新近发现蛋白纳米颗粒稳定的皮克林乳液具有一种优越的冻融稳定性，这为有望解决该问题提供了一条重要的技术解决方案。本项目拟通过构建具有一定凝胶样网络结构的蛋白颗粒稳定的皮克林乳液的技术途径，实现显著改善其冻融稳定性的目标，并揭示其改善机理。首先，研究具有增强冻融稳定性的“皮克林”蛋白纳米颗粒的转化途径及乳化性质；其次，研究相关皮克林乳液的物化、微结构特征及流变性质，以及冻融稳定性，并揭示乳液微结构或流变性质与冻融稳定性之间的相关性；接着，研究凝胶样皮克林乳液强化冻融稳定性的途径，并揭示相关机理；最后，验证蛋白纳米颗粒替代（或部分替代）蛋黄研发高冻融稳定性酱或其他乳液制品的可行性。研究结果不仅可丰富乳液冻融稳定性的科学认知，而且也为研发高品质酱或其他乳液制品提供一种有效的技术解决方案。

诸多现代食品中广泛使用的各种酱料（如蛋黄酱）大多属高油相比例（ø）的水包油乳液，后者的冻融稳定性直接影响相关食品的品质。不仅如此，蛋黄酱中使用的乳化剂（即蛋黄）含有较高含量的胆固醇，对相关制品带来了一定的健康风险。鉴于此，本项目旨在探索采用蛋白纳米颗粒替代蛋黄作为乳化剂制备一类无胆固醇的蛋黄酱的可行性及有效性，而且还期望赋予后者一种优越的冻融稳定性。基于前期研究发现，本项目首先研究了在中性条件下大豆分离蛋白（SPI）纳米颗粒稳定的皮克林乳液的冻融稳定性，以及其结构特征与冻融稳定性之间的构效关系；其次，探索了SPI在pH 3.0条件下作为唯一的稳定剂制备高冻融稳定性的高内相乳液（HIPEs）的实现途径，并揭示相关分子机制；之后，验证了SPI作为唯一的稳定剂制备高冻融稳定性的蛋黄酱的可行性及有效性；最后，还研究了SPI与壳聚糖复合物作为稳定剂应用于制备一类全新的高冻融稳定性的蛋黄酱的可行性及有效性。经过4年的系统研究，取得了系列的研究进展及成果，达到了预期的研究目标，包括：（1）发现在中性条件下SPI纳米颗粒稳定的皮克林乳液的冻融稳定性与其粒径及表面疏水度紧密相关；（2）SPI在pH 3.0条件下具有优越的形成高冻融稳定性的HIPEs的能力，而对SPI进行预热处理可显著增强此能力；（3）确证经热处理的SPI作为唯一的稳定剂可获得一类高冻融稳定性且无胆固醇的蛋黄酱；（4）发现SPI与壳聚糖复合物也可用于制备高冻融稳定性的蛋黄酱。相关研究结果已（待）发表学术论文15篇，其中SCI国际期刊13篇（3篇正在修回中）。相关成果不仅丰富了食品级的皮克林乳液(或HIPEs)的冻融稳定性的科学认知，而且也为研发高冻融稳定性且无胆固醇的蛋黄酱制品提供了一种有效的技术解决方案。