可溶性肽对肽纳米颗粒乳状液稳定性影响研究

The frabrication of particle emulsifiers from vegetable proteins is one of the focuses of food science research. However, the existing vegetable protein-based particles are defective in common, which cant not reach the demand of food industry. This research will introduce soluble soy peptide into soy nano-particles to frabricate mixed emulsifiers in order to resolve the creaming of emulsions stabilized by soy nano-particles. The effect of conditions of enzymatic hydrolysis and the structure of peptides on the stability of the emulsion will be investigated, imploying oil-droplet size, creaming-index and peroxide value as the indictors. The adsorption behaviors, including adsorption rate, arrangement model and net structure, will be studied by interface tensiometry, confocal laser scanning microscopy and scanning electron microscopy. The compisition, morphology and viscoelasticity of interfacial films will be studied using high-performance liquid chromatography and interfacial rheometer. At last, the relationships among interfacial adsorption behavior, rheological behavior of the interfacial films and emulsion stability will be analysed to elucidate the stability mechanism of the emulsion. This investigation will provide some theoretical basis on development of new emulsifers.

植物蛋白分子的颗粒化剂逐渐成为食品领域的研究热点。然而，现有技术制备的植物蛋白颗粒乳化剂普遍存在着缺陷，不能满足行业需求。本项目针对大豆肽纳米颗粒稳定的乳状液抗分层稳定性差的问题，将可溶性肽引入大豆肽纳米颗粒构建复合乳化剂，利用二者在界面上的优势来修饰界面膜结构以达到改善乳状液稳定性的目的。拟以酶水解度、肽段结构为参数，研究乳状液在储藏过程中粒径、分层指数、过氧化值的变化，阐明乳状液稳定性的变化规律；利用界面张力仪、激光共聚焦显微镜、扫描电镜等分析技术表征蛋白质颗粒在油水界面的吸附速率、排布规律、网络结构等吸附行为；采用高效液相色谱、凯氏定氮仪、界面流变仪研究乳状液界面膜的组成、形貌、zata-电位、粘弹性等性质；将酶水解度、肽段分子结构与乳状液稳定性、界面吸附行为、界面膜性质进行关联，探讨可溶性酶解物结构对肽纳米颗粒乳状液稳定性的影响机制，为新型食品乳化剂的开发提供理论依据。

植物蛋白分子的颗粒化剂逐渐成为食品领域的研究热点。然而，现有技术制备的植物蛋白颗粒乳化剂普遍存在着缺陷，不能满足行业需求。本项目针对大豆肽纳米颗粒稳定的乳状液抗分层稳定性差的问题，将可溶性肽引入大豆肽纳米颗粒构建复合乳化剂，利用二者在界面上的优势来修饰界面膜结构以达到改善乳状液稳定性的目的。研究结果表明低水解度的可溶性肽适量添加能够降低大豆肽纳米颗粒的平均粒径，增大其界面吸附速率及吸附后重排程度，增强大豆肽纳米颗粒的乳化活性，增强乳液的黏度，增强界面膜的粘弹性，进而增强乳液的分层稳定性。小分子量肽段会使大豆肽纳米颗粒发生聚集从而降低其乳化活性和乳化稳定性。界面膜厚度不是引起大豆肽颗粒乳液分层的关键因素。另外，本项目在研究中发现乳液液滴疏水聚集是引起乳液失稳的重要原因，因此本项目在大豆肽纳米颗粒乳液中引入壳聚糖制备大豆肽纳米颗粒-壳聚糖双层乳液，该双层乳液具有良好的絮凝稳定性和分层稳定性，环境因素对乳液性质影响较小，可以用于脂溶性化合物的保护。本项目为大豆肽纳米颗粒在稳定的食品、药品及化妆品乳液中的应用提供了重要数据支撑。