热加工中海参体壁胶原蛋白组织原位变化及物性影响机制

Due to unique nature of the processing, sea cucumber would have good texture if the heat treatment is appropriated; the inadequate or excessive heat treatment would make sea cucumber too hard or too soft. The physical property changes of heat treatment of sea cucumber were generally considered as associated with collagen. But how does the structural change of collagen in the heat treatment affect the physical property of sea cucumber? How does the glycosaminoglycan existing between the collagen fibers affect the structural changes of collagen, in turn, affect the physical property of sea cucumber? This project aims to systematically study the above problems. Firstly, using HPLC-MS/MS, fourier transform Infrared spectroscopy, rheometer and texture analyzer, in vitro denaturation-renaturation behavior of the collagen molecules and collagen fibers will be studied to clarify the relationship between the changes of collagen protein molecular structure and physical properties. The in vitro-behavior study of the degeneration of the collagen fibers will clear the effects of glycosaminoglycan on the degradation of collagen fibers and the effects of gel-forming ability. And then, Using infrared microscopy imaging techniques, the in-situ dynamic changes of the distribution and the structure change of collagen and glycosaminoglycan, which are the major components of sea cucumbers body wall will be studied in the thermal processing, which will reveal the regular pattern of the in-situ molecular structure of sea cucumber body wall. The results of this study will further reveal the regulatory mechanism of the change of the main components and the texture of the sea cucumber body wall in thermal processing, which will provide the theoretical basis for deep processing of sea cucumber.

海参加工性质独特，鲜海参热处理适宜，产品具有良好质构；热处理不充分或过度，产品则过硬或软烂。海参热加工中的物性变化，普遍认为与其胶原蛋白密切相关。但热加工中胶原蛋白结构变化如何影响海参物性变化？存在于胶原纤维间的粘多糖如何影响胶原蛋白结构的变化进而影响海参物性？本项目拟对上述问题进行系统研究。首先，利用液相串联四极杆质谱、傅立叶变换红外光谱、流变仪、质构仪等，研究胶原纤维的变性-复性行为，以及粘多糖对胶原纤维降解和凝胶形成能力的影响，明确胶原分子结构变化与海参物性变化的关系。然后，在组织原位水平，利用红外显微成像技术，研究热加工中海参胶原蛋白和粘多糖的动态分布及结构变化，明确其变化规律，与已建立的海参物性变化规律进行相关性研究，进而揭示热加工中海参胶原蛋白变化对海参物性的影响机制，为海参深加工提供理论依据。

海参加工性质独特，鲜海参热处理适宜，产品具有良好质构；热处理不充分或过度，产品则过硬或软烂。海参热加工中的物性变化，普遍认为与其胶原蛋白密切相关。本项目分别提取海参体壁中的粗胶原纤维和酶促溶性胶原蛋白，对两种胶原热处理过程中的结构和性质变化进行了对比；其次，考察了胶原蛋白与粘多糖不同比例混合后的理化特性变化；最后，利用红外显微成像分析不同加工条件下海参体壁中胶原蛋白的原位分布变化。结果发现，海参胶原纤维的变性温度为46.1 ℃，酶促溶性胶原蛋白的变性温度为35.3 ℃，说明胶原纤维热稳定性较酶促溶性胶原蛋白要高。加热过程中粗胶原纤维和酶促溶性胶原蛋白的酰胺I带遭到严重破坏，α-螺旋结构逐渐向β-折叠等其他二级结构转化，β-折叠结构的变化先于α-螺旋结构的变化；在冷却过程中，二级结构会随温度的降低有所回复，胶原纤维的复性能力强于酶促溶性胶原蛋白。海参酶促溶性胶原蛋白与粘多糖共混后，粘多糖会使胶原蛋白与水的结合能力发生变化，从而影响胶原蛋白的变性温度，促进胶原蛋白的成纤维能力，使胶原蛋白的有序高级结构发生重组。以上研究成果发表SCI收录论文4篇，EI收录论文1篇，中文核心期刊论文1篇，培养硕士研究生3名，申报中国发明专利1项，为进一步揭示热加工中海参质构变化机制奠定了很好的基础。