低碳农产品芭蕉芋源膳食木质素作用消化酶的机理研究

In comparison with potato, Canna edulis Ker cultivated mainly in poor mountainous area at Southwest of China is an important low-carbon agricultural product with good development prospect. To our best knowledge, up to now, a great deal of dietary lignins found in Canna edulis Ker residue obtained after starch extraction have not been well utilized and its effects and mechanisms on digestive enzyme activities have not also been studied. Our project will explore the binding mode of Canna edulis Ker lignins on the enzymes and the mechanism that the lignins affect the enzymes at the molecular level. We will study dietary lignins with different molecular weights, which will be extracted from Canna edulis Ker residue, and the enzymes which digest carbohydrate, protein, and lipid. Through the combination of modern analytical techniques and the theories, we will test, calculate, and analyze the structural properties of the lignins and the enzymes themselves, their binding parameters including the binding force, the binding distance, and the binding sites, and the changes of enzymes properties such as the particle sizes, aggregation state, special conformation, and stability et al. The techniques referred include molecular fluorescence spectroscopy, total reflection Fourier transform infrared spectroscopy, circular dichroism, dynamic light scattering, small-angle X-ray scattering, and differential scanning and the theories contain thermodynamics, quantum chemistry, molecular mechanics, and molecular simulation. In a word, our project will provide a scientific basis for the development of high value-added Canna edulis Ker residues, reduction of environmental pollution caused by Canna edulis Ker processing, and the application of dietary lignins in the food field.

芭蕉芋为主产于我国西南贫困山区的一种比马铃薯更具发展前景的重要低碳农产品，课题针对提取淀粉后的芭蕉芋废弃残渣中含有大量膳食木质素未被利用且污染环境，而膳食木质素对消化酶活性的作用机制又尚不清楚的现状，在已有的芭蕉芋系列研究基础上，进一步以从芭蕉芋残渣中提取得到的不同分子量膳食木质素分别与碳水化合物、蛋白质及脂肪消化酶形成的体系为研究对象，采用荧光光谱、全反射傅里叶转换红外光谱、圆二色谱、动态光散射、小角X射线散射等多种现代分析技术，结合热力学、量子化学、分子动力学、分子模拟等理论方法，通过测试、计算、分析木质素与各酶蛋白的结构性质，相互作用的结合力、结合位点、结合距离，及酶蛋白在作用前后聚集状态、空间构象和稳定性的变化等，找寻木质素-消化酶的结合方式，在分子水平上揭示膳食木质素作用消化酶的机理，为芭蕉芋残渣高附加值开发、减轻芭蕉产业的环境污染，及膳食木质素在食品领域的应用普及提供科学依据。

芭蕉芋作为我国重要的食物原料和经济作物，主要用于工业中淀粉的生产，其提取淀粉后会产生大量的残渣。芭蕉芋残渣中含有大量的膳食木质素，近年来，虽然国内外学者逐渐认识到膳食木质素能有效延缓人体对葡萄糖的吸收，调节血糖水平等生物学功能。但是对于其在生物体内如何影响三大宏量营养素，即碳水化合物、蛋白质和脂肪的代谢，特别是其本身不被消化酶所分解，而反过来却影响消化酶的活性，其作用机制是什么这个基本核心问题，相关研究迄今为止还是空白。因此，揭示膳食木质素与消化酶作用机制，深入全面了解其对代谢的作用，对正确认识木质素的生物学功能具有重要的科学价值。.本项目提取、分离、鉴定芭蕉芋残渣膳食木质素，采用荧光光谱、红外光谱、圆二色谱、核磁共振等分析技术手段，结合热力学、分子动力学等理论方法，综合分析木质素与酶蛋白的作用性质（结合力、结合位点、结合距离，及酶蛋白在作用前后的空间构象变化），探究木质素——消化酶的结合方式，从分子水平上揭示膳食木质素与消化酶的作用机制，为芭蕉芋残渣的开发应用提供理论基础。