超高压诱导鸭肝蛋白熔球态形成对腥味物质结合能力的影响机制

作为肉鸭分割环节的主要副产物，鸭肝营养丰富、质地柔嫩，但腥味强烈已成为制约其消费与加工的关键因素。申请人前期研究发现超高压力场显著削弱腥味感知，且蛋白熔球态（MGs）转变过程与鸭肝腥味削弱相关，推测MGs形成增强了腥味化合物的结合能力，但结合机制有待探索。本项目在表征鸭肝特征腥味物质的基础上，通过对比典型蛋白态与特征腥味物质结合曲线、结合位点与结合方式等特性的差异，明确MGs蛋白二级结合位点形成及其去腥效应；基于多谱学表征系列差异化MGs蛋白多级结构特征及其对应的腥味物质结合行为，分析MGs形成与特征腥味组分结合前后的熵焓效应，阐明构象熵参与的MGs蛋白与腥味组分结合行为的关联机制；采用纯蛋白构象扰动体系与分子模拟验证两者的关联机制。研究结果有助于理解蛋白与风味物质相互作用的共性机制，为非热场定向调控肉类风味及鸭肝高值化应用奠定基础。

Duck liver (DLv), as a major byproduct of duck segmentation, presents highly nutritional and tender characteristics, but strong off-flavor limits its consumption and industrial development as a key factor. Our previous results have demonstrated that DLv samples subjected to ultra-high pressure field (UhpF) presented a decreased off-flavor perception. And it was also confirmed that the formation process of molten globule-state (MGs) protein was related to the off-flavor decease. Thus, it is inferred that MGs formation increases the binding capability of off-flavor components from DLv samples under high-pressure conditions, but the specific binding mechanism requires further investigation. This project first identifies qualitatively and quantitatively the characteristic off-flavor compounds in DLv samples; and the interactions between the characteristic off-flavor compounds and the typical protein structures, including native, MGs and completely unfolded proteins, are investigated. Thus, the binding curves, binding sites, and binding patterns are precisely described, to clarify and confirm the role of MGs in off-flavor perception reduction, as well as the formation of secondary binding sites. Then, based on the multi-spectrum characterization, the multi-level microstructures of a series of differentiated MGs proteins are characterized, as well as their corresponding binding behavior, and simultaneously thermodynamic effects before and after MGs formation and volatiles binding are analyzed, in order to clarify the conformational entropy-mediated correlation mechanisms between MGs protein and binding behavior of characteristic off-flavor components. Finally, the correlation mechanisms are validated by employing the conformational disruption of the pure protein system and molecular simulation. Research results will help to obtain an in-depth understanding of general mechanisms governing the interaction between protein and flavor compounds, as well as to provide a theoretical basis for nonthermal physical field-based meat flavor regulation and the development of high value-added DLv products.