高强度脉冲电场作用下蛋白质分子的去折叠、复折叠与聚集行为及稳定方法

Pulsed electric fields (PEF) is one of the most promising non-thermal food processing technologies as the potential complement to or replacement of thermal pasteurization. Although the PEF equipment with capacity of 20m3/h has been built, there is still a doubt for the commercial application, because the mechanisms and effects of PEF processing on food ingredients, food quality and safety are not fully clear. This study is to investigate the process and dynamics of protein unfolding under PEF treatments. The characterization of precise structures of partly unfolded protein, thermodynamic and kinetic analysis of unfolding, refolding of protein, molecular interaction and aggregation under PEF would be involed in this study. Accordingly, the mechanisms and process of the unfolding of protein under PEF would be proposed. The detail of molecular motion and the more accurate information about the structure and function of protein without the disturbance of protein aggegates under PEF could be further obtained. Finally, the more accurate relationship beween the structure and function of protein under PEF would be established. The protein-protein interaction, aggregation in different protein systems and the nature of the chemical bonds involved would be clear. Finally, the relationship between PEF treatments, unfolding, refolding and aggregation of protein and food processing characteristics would be established. The methods to stabilize the protein in PEF processing would be proposed, making a very effective guidline for the PEF processing of protein-based foods.

高强度压脉冲电场（pulsed electric fields, PEF）杀菌技术是正在发展的适合于大宗热敏性流体食品连续杀菌的非热食品加工技术。本课题通过对PEF作用下蛋白质去折叠的动态结构变化及动力学分析，PEF作用产生部分折叠蛋白质中间体的精确结构分析，PEF作用后的蛋白质的去折叠、复折叠的热力学和动力学分析、分子聚集行为分析，获得PEF作用下蛋白质去折叠过程与规律，揭示蛋白质分子运动的细节与蛋白质结构改变全貌；获得消除蛋白质聚集干扰的更精确的PEF 作用下蛋白质结构与功能变化信息，构建更加准确的构效关系模型；明确PEF作用不同蛋白质体系的蛋白质聚集行为、聚集驱动力；明确PEF作用后的蛋白质的去折叠、复折叠、聚集规律，最终建立PEF作用、蛋白质去折叠、复折叠、聚集、食品加工特性的关系模型，提出PEF处理过程中蛋白质的稳定方法，形成对复杂食品体系PEF加工具有普遍指导意义的结论。

高压脉冲电场（pulsed electric fields，PEF）杀菌技术与传统巴氏杀菌技术相比，具有处理时间短、能耗小且加工过程中食品组分变化小等优势，是一项有希望应用于大宗流体食品连续杀菌的非热加工技术。液态蛋使用方便，运输简单，目前的巴氏杀菌工艺往往会使鸡蛋中的热敏性成分发生聚集絮凝，降低产品品质。因此，将PEF技术应用于液态蛋的加工具有广阔的市场前景。但是，高压脉冲电场技术的研究主要集中在液态食品如果蔬汁的杀菌保鲜以及对固体食品的物质转移两个方面，而蛋白质在PEF作用下的聚集机理与稳定机制尚未得到充分研究。因此本项目侧重于对PEF处理下蛋清蛋白溶液的稳定性进行研究，对聚集形成的机制进行探讨并研究抑制聚集形成的方法，推进PEF技术在液态蛋等富含蛋白质食品加工中的应用。以蛋清溶液中3种主要蛋白质——卵白蛋白、溶菌酶和卵铁传递蛋白为对象，研究在PEF处理过程中模拟体系中的蛋白质之间的相互作用以及所形成的聚集体类型，并对聚集体之间的作用力进行了研究。以稀释蛋清溶液为研究对象，比较蛋清蛋白体系在热处理与PEF处理下发生聚集的机制异同，对蛋清中不同组分对聚集行为的影响进行考察，为后续对抑制聚集行为的研究奠定基础。分别以蛋白质和多蛋白胶体为研究对象，根据得到的理论，提出PEF作用下蛋白质的稳定方法与机制。以高浓度蛋清溶液为研究对象，研究了柠檬酸的加入对PEF杀菌效果的影响，此外，研究了柠檬酸的添加对产品的功能性质的影响，为PEF技术在实际蛋清制品加工中的应用提供建议和参考。