蒸汽闪爆纤维状蛋白质非专一性酶高效降解机制研究

High-value utilization of low value protein materials through enzymatic modification is an active research field in the food science presently. It has been proven that proper pretreatment will obveriously enhance the enzymatic efficiency of protein, which is one of the key points to keep under controllable state. In our preliminary research, steam flash explosion (SFE) could efficiently depolymerize the aggregation structure of fibrous protein such as feather keratin. Thus, we speculate that SFE might improve the non-specific enzymolysis of fibrous protein. This study focuses on two key scientific problems: the effect of SFE on the structure of fibrous protein such as fish scale and fish skin, and how changes in the structure affect the enzymatic hydrolysis of the pretreated materials. The effects of SFE on the protein structure will be mainly investigated, such as the spectral characteristics and microstructural features of protein molecules, and then establish the relationship between the structural features and enzymolysis characteristics of the protein. With the study of factors of enzymolysis and the reaction kinetics of enzyme catalysis, the reason why SFE could improve non-specific enzymatic hydrolysis could be revealed at the molecular level. Finally, an applicable pretreatment for fish scale and fish skin materials would be proposed, establishing an effective method for the promotion of non-specific enzymolysis of low value aquatic protein.

大宗低值蛋白资源通过酶解改性高值化利用是目前国际上活跃的研究领域。国内外研究表明适当的预处理可显著提高原料的酶解效率。本项目基于申请者前期发现蒸汽闪爆可解聚羽毛角蛋白等纤维状蛋白质聚集态结构的实验结果，以鱼鳞、鱼皮等代表性纤维状蛋白质为研究对象，围绕蒸汽闪爆对纤维状蛋白质结构的影响及其促进非专一性酶降解机制两个关键科学问题，重点评价蒸汽闪爆处理的酶解效果，通过研究蒸汽闪爆对纤维状蛋白质分子波谱特性与微观结构特征的影响，建立蛋白质的波谱特性、结构特性与其酶解特性之间的关系，并结合蒸汽闪爆处理后蛋白质酶解影响因素、酶促反应动力学研究，从分子水平和化学反应动态学角度揭示蒸汽闪爆促进纤维状蛋白质非专一性酶高效降解的原因，进而提出适合于鱼鳞、鱼皮原料的蒸汽闪爆预处理方式和酶解工艺，为提高低值水产蛋白资源酶解效率提供理论依据。

大宗低值蛋白资源可通过酶解改性处理提高资源利用率。水产品加工过程中会产生大量的鱼皮、鱼鳞、鱼骨等下脚料，含有大量纤维状蛋白质。这一蛋白资源的独特结构使其难以被直接酶解利用。如何对原料进行预处理提高其酶解特性尤为关键。本项目以水产品加工中产生的鱼皮、鱼骨等代表性纤维状蛋白质为研究对象，研究汽爆处理对纤维状蛋白质结构解离及其促进非专一性酶降解机制，获得对纤维状蛋白资源降解规律，从而实现提高水产品加工中难利用蛋白资源利用率的目的。研究发现汽爆处理可弱化纤维状蛋白质与羟基磷灰石等基质间的交联程度，增大纤维蛋白分子链间距，改变肽段间分子间相互作用模式，破坏胶原三螺旋结构。尿素体系凝胶电泳分析表明汽爆压力超过0.4 MPa时，肽链开始大量断裂，纤维状蛋白质在解离的同时发生聚集。研究发现0.6 MPa汽爆处理能够有效促进鱼皮、鱼骨中蛋白的溶出和肽段的解离，提高纤维状蛋白质的酶解特性，其中蛋白质溶出率和水解度是未处理样品的5~8倍。经汽爆处理鱼皮、鱼骨暴露出更多的酶切位点，使其对非专一性蛋白酶具有较高的酶解敏感性，进而可显著改善纤维状蛋白酶解物的性能。本项目采用汽爆处理对纤维状蛋白质进行适当预处理，提高非专一性蛋白酶酶解敏感性，再利用商品蛋白酶控制酶解，可显著改善鱼皮、鱼骨酶解物性能。本研究为汽爆处理引起纤维状蛋白质结构及酶解特性的改变提供依据，也为低值蛋白资源开发及其食品加工性能的改善提供了新途径。