低温长时间热处理对刺参体壁质构特性的影响及分子机理研究

The body wall of sea cucumber is a type of mutable collagenous tissue (MCT), which has unique processing property and its texture is hardly to be controlled. Low-temperature long-time (LTLT) heat treatment can effectively control the textural properties and then improve the edible quality of sea cucumber bodywall. Our previous studies have shown that both heat and endogenous enzymes under processing conditions result in changes of microstructures and the phase state and distribution of water of MCT during heat treatment, which is the ultimate cause of the texture development. However, the molecular mechanism and enzymological mechanism for texture development during LTLT heat processing of sea cucumber is still unclear. According to the above problem, the present project is aimed to investigate the relationships between changes of the hierarchical structures from molecules to macromolecules level of MCT, changes of content and distribution of water of different phases, and changes of textural and mechanical properties by utilizing TEM histochemistry, IMI, SHGI, HPLC-MS, LF-NMR, texture profile analysis, rheology analysis, etc. In this way, the molecular mechanism for texture development during LTLT heat-induced processing of sea cucumber will be revealed. At the same time, enzymological mechanism of action for texture development during LTLT heat-induced processing of sea cucumber will also be elucidated by demonstrating the changes of endogenous enzymes activity and their effects on the structural changes in protein molecules, macromolecules and microstructures. The knowledge gained in this project is expected to innovate the texture research method of LTLT heat-induced sea cucumber, and provide theoretical support for establishing the texture control technology and improving of texture properties of LTLT heat treatment sea cucumber.

海参体壁属可变胶原组织（MCT），加工性质独特，质构不易控制。采用低温长时间（LTLT）热处理技术可有效控制海参质构、提升食用品质。前期研究表明，在热和内源酶的共同作用下，热加工海参体壁MCT的微观结构和水分状态均发生改变，是其质构变化的根本原因。然而，LTLT热加工海参质构形成的分子机理和酶学机制尚不清楚。针对上述问题，本项目拟采用电镜及组织化学、红外显微成像、二次谐波成像、高效液相色谱质谱联用、低场核磁共振波谱、质构仪、流变仪等技术手段，研究LTLT热处理过程中刺参体壁MCT从分子到超分子的各层级结构阶段式变化、各相态水分含量及流动性变化与质构特性变化间的内在联系，阐明质构形成的分子机理；通过揭示内源酶活力变化及其在MCT各层级结构变化中发挥的作用，阐明质构形成的酶学机制。通过本研究，将创新LTLT加工食品质构研究方法，为建立热加工海参质构调控技术、改善热加工海参质构特性提供理论支撑。

海参体壁属可变胶原组织（MCT），加工性质独特，质构不易控制。低温长时间（LTLT）热处理技术可有效控制海参质构，提升食用品质。热处理过程中，在热、内源酶和氧的共同作用下，海参体壁MCT质构特性发生变化，但其形成机制尚不明确。本项目以此为研究背景，对不同条件热处理后的海参体壁采用质构仪、低场核磁共振波谱、扫描电镜（SEM）、透射电镜（TEM）、二次谐波成像（SHGI）、红外光谱（FTIR）、电子自旋共振波谱（ESR）、差式扫描量热（DSC）、电泳、高效液相色谱（HPLC）、化学分析等技术，从感官品质、质构特性、水分相态和分布、微观结构、超分子结构、胶原蛋白二级结构、胶原变性、凝胶化和氧化及关键结构因子降解溶出等多维度多层次，综合分析探究了海参体壁LTLT热处理过程中质构特性的形成机制；采用在组织原位抑制内源酶活性的方式，通过总酶活力测定、酶活性荧光染色和组织化学染色、质构分析、水分分析、微观结构观察、胶原变性降解溶出等多维度多层次指标，初步探究了内源酶在LTLT热处理海参体壁质构形成过程中的作用机制；以胶原纤维为模型，分别氧化或/和加热处理不同时间，通过SEM、DSC、ESR、FTIR、HPLC及化学分析等方法，从微观结构、变性程度、氧化程度、二级结构、溶出性成分分子量排布及关键结构因子降解溶出等层面，综合分析了氧化对LTLT热处理过程中海参体壁胶原纤维的影响。本研究结果为创新LTLT热加工食品质构的研究方法，建立热加工海参质构调控技术、改善热加工海参质构特性提供理论基础。截止目前，项目相关研究内容发表SCI论文2篇，授权实用新型专利1件，培养硕博研究生4名。此外，以项目相关研究结果为基础，申报获批市级项目1项。