鱼糜蛋白质与脂质交互作用对凝胶脆性形成的影响及其机制研究

The production of fish surimi and surimi seafoods is one of the most important industry of the world's aquatic products fine processing industry. However, the marketing degree of surimi products processing and circulation is very low in China, and the main reason is that the current high visco-elasticity pursuit of surimi products originating from Japan doesn’t meet domestic consumers, who traditionally love surimi products with both good fracturability and elasticity, just like pork balls. The development of new surimi product which is suitable for the domestic consumers is imminent. Preliminary studies showed that the addition of lipids could dramatically improve the fracturability of surimi gels, but the mechanism underlies is still not clear. The present project aims to study the effect of different lipids on the gel properties of surimi gels firstly, and then study the changes of lipids on the surimi protein globular micelle interface, surimi protein secondary structure, water distribution of surimi gels and the interaction between lipid and protein of surimi gels. The results will reveal the structure-activity relationships among the surimi gel’s microstructure, surimi protein conformations, and and fracturability of surimi, and clarify the inducing effects of lipids on the fracturability of surimi gel and the underlying mechanism. Through the present study, the development of surimi products with novel texture properties catering for domestic consumers will be promoted, and the domestic demand of surimi products will be expanded. Moreover, the results of the present study will provide theoretical basis and technical support for the full development and utilization of fish resources in China.

鱼糜及其制品是世界水产品精深加工最重要的内容之一，但我国的鱼糜制品加工和流通市场化程度较低，其主要原因是当前日式鱼糜制品追求的高弹性无法迎合我国消费者对富有一定弹性下兼具贡丸样脆性产品的传统特色要求，开发适于我国消费市场的新型鱼糜制品迫在眉睫。课题组前期的研究表明，脂质类物质的添加可显著改善鱼糜制品的凝胶脆性，但目前对其形成机理仍未有相关研究。本课题拟在研究不同脂质对鱼糜蛋白-脂质复合凝胶特性影响的基础上，分别从脂质对鱼糜蛋白质球状胶束界面影响、脂质对鱼糜蛋白质构象及凝胶体中水分分布影响、脂质与鱼糜蛋白质分子间交互作用等多角度展开分析研究，揭示新颖鱼糜制品微观结构及蛋白质构象与凝胶脆性的构效关系，阐明鱼糜蛋白质与脂质互作对鱼糜凝胶脆性形成的影响及其机制。通过本研究将促进广受我国消费者喜爱的优良凝胶特性新颖鱼糜制品开发、扩大鱼糜制品内需，为充分开发利用我国鱼糜资源提供理论依据和技术支持。

本研究着重阐明了不同脂质对鱼糜凝胶脆性等质构特性的影响及其作用机制。主要取得以下四个方面的研究成果：（1）以冷冻鱼糜为原料，分析了不同脂质（动物、植物油脂、磷脂、鱼油等）以及不同脂质浓度对鱼糜复合凝胶特性的影响，阐明了鱼糜乳化稳定性、流变特性、微观结构及鱼糜凝胶脆性等质构特性的变化规律；（2）通过油脂表面的蛋白界面膜研究，探究了鱼糜蛋白质凝胶形成过程中肌原纤维蛋白与油脂相互作用的机制，阐明了脂质对鱼糜蛋白质球状胶束界面的作用规律及其改变界面膜的扩张流变特性；（3）揭示了脂质添加对鱼糜蛋白质构象与凝胶水分分布的影响，脂质添加后蛋白质分子的疏水残基暴露，蛋白质分子发生聚集，鱼糜凝胶中的蛋白质二级结构α-螺旋含量降低，β-折叠含量升高，凝胶体系中的自由水向结合水和不易流动水转化；（4）分析了鱼糜蛋白质与脂质大分子间的交互作用，阐明了脂质与鱼糜蛋白质互作对鱼糜凝胶脆性形成的影响及其机制，相关性分析表明，鱼糜凝胶脆性的增加主要与蛋白质二级结构α-螺旋的含量呈显著性负相关，与β-折叠、β-转角、无规则卷曲的含量及疏水相互作用呈显著性正相关。该研究可为改善鱼糜凝胶特性，提高鱼糜制品市场占有率、高值化利用我国鱼糜资源提供可靠的理论依据和技术保障。