疏水性褐变抑制剂协同/竞争界面乳液的构建及其对果蔬酶促褐变影响

Enzymatic browning is the main reaction which induces the occurrence of browning in fruits and vegetables during their storage, transportation and processing. At present, the application of natural browning inhibitors in inhibiting browning of fruits and vegetables becomes a research hotspot. As noted in previous researches, lots of natural browning inhibitors such as apigenin exhibited good inhibitory activities of polyphenol oxidase, but the poor aqueous solubility and instability of these inhibitors limit their application in fruits and vegetables. Although the aqueous solubility and stability of hydrophobic browning inhibitor could be improved by encapsulating in emulsion delivery systems, the principle of fabrication of hydrophobic browning inhibitor loaded emulsion delivery systems is still unknown, and the influence of hydrophobic browning inhibitor loaded emulsion delivery systems on enzymatic browning of fruits and vegetables should be further discussed. Therefore, staple fruits and vegetables (pear, Chinese yam and lotus root) will be employed as research objects, apigenin will be employed as model of hydrophobic browning inhibitor, and synergetic/ competitive interface emulsion delivery system will be fabricated from the regulation of the composition and microenvironment in the present project. The change in the structure, physico-chemical and stability properties of synergetic/ competitive interface emulsion delivery system will be characterized. Meanwhile, dissipation dynamics simulation will be carried out to explore the inner relationship and feedback adjustment among structure, physico-chemical and stability properties, which aims to achieve ideal fabrication of hydrophobic browning inhibitor loaded synergetic/ competitive interface emulsion delivery system. The difference in enzymatic browning reaction of fruits and vegetables light processing products treated by above emulsion delivery system will be monitored, and the data mining model will be established to explore the influence of above emulsion delivery systems on the enzymatic browning of fruits and vegetables light processing products. It could provide theory and technical reference for the influence of hydrophobic browning inhibitor encapsulated in emulsion delivery system on enzymatic reaction and its application in fruits and vegetables.

酶促褐变是引起果蔬贮运加工中褐变发生的主要反应。目前关于天然褐变抑制剂用于果蔬酶促褐变抑制是国内外研究的热点。课题组前期发现芹黄素等疏水性褐变抑制剂虽有较好的多酚氧化酶抑制活性，但其低水溶性与不稳定性极大地限制了其在果蔬中应用。乳液递送体系虽可提高疏水性褐变抑制剂的水溶性和稳定性，但疏水性褐变抑制剂乳液递送体系的构建基础及其对果蔬的酶促褐变影响尚不明确。为此，本项目拟以大宗果蔬为对象，芹黄素等为疏水性褐变抑制剂模型，通过组分差异和微环境变化制备疏水性褐变抑制剂协同/竞争界面乳液递送体系；表征其结构物化与稳定特性，结合耗散动力学模拟探讨其内在匹配关系和反馈调节，实现乳液递送体系的理想构建；表征处理果蔬轻加工制品酶促褐变特性参数的差异，构建数据挖掘模型阐明协同/竞争界面乳液递送体系对果蔬酶促褐变影响，为乳液递送体系中疏水性褐变抑制剂的酶促反应影响提供理论参考及其在果蔬保鲜领域应用提供技术支持。

天然的疏水性褐变抑制剂用于果蔬酶促褐变抑制是国内外研究热点。然而天然的疏水性褐变抑制剂存在水溶性低和稳定性差的问题，极大地限制了其在果蔬中应用。本研究通过乳液组分和微环境变化调控组分间相互作用构筑高稳定性的协同/竞争界面乳液，高效负载疏水性褐变抑制剂，并考察其应用于不同易褐变果蔬上对果蔬颜色、酶活性和活性氧代谢等品质的影响，进而评估该保鲜乳液的抗褐变机制和应用前景。主要内容有（1）调整复合纳米粒子的颗粒大小和组成改变乳液界面吸附性质和稳定性；微环境变化可调控不同乳化剂的界面吸附能力，调整其负载能力和粒子特性等；通过改变精油比例调控甜橙精油与酪蛋白酸钠之间的协同/竞争吸附性质，优化乳液物理稳定性和氧化稳定性等；通过组分差异和微环境变化构建甜菜果胶-单宁酸-壳聚糖三元复合物的协同/竞争界面高内相乳液，高含量包埋和释放姜黄素。（2）低含量刺梨原浆可有效控制常温鲜榨苹果汁的酶促褐变，归咎于其较高的抗坏血酸、酚酸和黄酮；水杨酸对多酚氧化酶的抑制作用受酸化和结合作用共同影响；4-羟基肉桂酸与柚皮素作为模型疏水抑制剂，表明pH对酚酸的影响远大于黄酮。（3）肉桂精油表面活性剂界面吸附乳液和抗坏血酸可协同抑制鲜榨苹果汁的酶促褐变；负载高良姜精油的表面活性剂界面吸附乳液的性质稳定并可改善菠萝汁稳定性、色泽和抑制微生物生长；负载肉桂精油的协同/竞争界面乳液可有效改善芒果颜色和总酚含量等指标，且效果优于常规乳液；挤压造粒法制备的复合精油负载的固体颗粒可有效改善鲜切百合鳞茎的褐变、外观品质和活性氧代谢等；负载肉桂酸、肉桂精油和水杨酸的协同/竞争界面的双重乳液可抑制苹果汁褐变和延长芒果保鲜效果。项目探究协同/竞争界面乳液稳定特性、结构物化与界面性质间的反馈调节，实现疏水性褐变抑制剂乳液递送体系的理想构建，阐析疏水褐变抑制剂乳液运载体系对果蔬褐变酶活性和代谢途径的影响，为其在果蔬保鲜领域的应用提供技术支持。