基于空间构象的岩藻聚糖硫酸酯-蛋白质静电自组装机制及复合物消化行为研究

The electrostatic self-assembly system of polysaccharides and proteins has an important application in the field of food processing, however, to clarify the mechanism of assembly as well as the regularity of digestion behavior is the key to achieve precise structural designs and targeting utilizations. This project intends to conduct in-depth studies on fucoidan (FUC) and sodium caseinate (NaCS) electrostatic self-assembly system based on the conformation of polysaccharide. First of all, we try to analyze the chain conformational differences of various FUC in the assembled environment, using HPSEC-MALLS-Visc-RI, dynamic light scattering, atomic force microscopy and other techniques; And, the electrostatic self-assembly system of FUC-NaCS will be constructed, to elucidate the microstructure and mechanism of the assembly by means of CLSM, Cryo-TEM, ITC, etc; Then, we will establish the interlinkages between the chain conformation parameters of FUC and the microstructure of the assembled complex based on the artificial neural network model. After that, this project will continue to explore the digestion behaviors of FUC-NaCS complex as following aspects: digestibility, microstructure changes, and the interactions between complex and gastric mucus layer. This project aims to reveal the internal relationship among FUC chain conformation, the microstructure of electrostatic assembly system and gastric digestion behavior of the complex from the view of the chain conformational differences of FUC, laying the theoretical foundation for realizing the targeted food microstructure and improving its digestion behavior.

多糖和蛋白质静电自组装体系在食品加工领域具有重要的应用价值，而明确其组装机制及其消化行为规律是实现复合结构精准设计和靶向应用的关键。本项目拟以多糖空间构象为切入点，对海参岩藻聚糖硫酸酯(FUC)与酪蛋白酸钠(NaCS)静电自组装体系展开深入研究。首先采用HPSEC-MALLS-Visc-RI、动态光散射、原子力显微镜等技术解析多种FUC在组装环境中的空间构象差异；同时构建FUC-NaCS静电自组装体系，利用CLSM、Cryo-TEM、ITC等手段阐明复合物的微观结构和组装机制，并基于人工神经网络建立FUC空间构象参数与复合物微结构的内在关联；最后利用体外胃消化和胃粘液层模型，考察FUC-NaCS复合物消化率、微观结构的变化及其与胃粘液层的作用方式。本研究旨在建立FUC空间构象、FUC-NaCS体系微结构与复合物胃内消化行为的相互联系，为实现调控食品微结构、提高品质与营养性能奠定理论基础。

多糖和蛋白质静电自组装体系在食品加工领域具有重要的应用价值，而明确其组装机制及其消化行为规律是实现复合结构精准设计和靶向应用的关键。本项目拟以多糖空间构象为切入点，对海参岩藻聚糖硫酸酯(也称岩藻多糖，FUC)与酪蛋白酸钠(NaCS)静电自组装体系展开深入研究。首先采用HPSEC-MALLS-Visc-RI、动态光散射、原子力显微镜等技术解析多种FUC在组装环境中的空间构象差异，发现FUC在溶液中表现为刚性链或柔顺链构象，一级结构中支链存在会显著影响其链构象参数；在此基础上构建FUC-NaCS自组装体系，利用CLSM、TEM和Nanosizer等手段阐明复合物的微观结构和组装机制，发现FUC与NaCS在酸性环境中可通过静电组装的方式形成纳米复合物，粒径分布在100-600 nm范围， FUC的分子量和链构象的刚性均会影响与复合物微结构的稳定；最后利用体外胃消化，考察FUC-NaCa复合物消化率、微观结构的变化及产物分子量和形态，结果表明，FUC与NaCS形成的纳米复合物可降低在胃蛋白消化过程中对蛋白水解度。长链FUC与NaCS形成的纳米复合物结构有助于原始NaCS结构的保持及降解过程中5-10 kDa肽段的积累。而低分子量多糖与NaCa形成的纳米复合物结构有助于5-10 kDa多肽的积累。本项目的结果建立了FUC空间构象、FUC-NaCS体系微结构与复合物胃内消化行为的相互联系，为实现调控食品微结构、提高品质与营养性能奠定理论基础。