超高压对荞麦球蛋白调节肠道菌群结构的影响及机理研究

There has been a close relation between health and gut microbiota. The latest studies revealed that buckwheat globulin as one of unique food resources in china had functional property of regulation of gut microbiota. However, the activities of buckwheat globulin were sensitive to be negatively affected during hot processing. Meanwhile, the regulation mechanism for relationship between gut microbiota and buckwheat globulin has not been fully clear. Ultra-high pressure treatment is one kind of new food processing technologies that could affect slightly flavor compounds and thermal sensitive compounds in foods, owing to low temperature, rapid speed, and homogeneity, which has a good application prospect. Therefore, the technological conditions of ultra-high pressure will be established and optimised for buckwheat globulin in the applied research project. The buckwheat globulin treated by ultra-high pressure will be focused on the stabilization for the globulin structure and the gut microorganism regulation. The low digestion and gut flora regulation of the globulin will be confirmed clearly via both in vitro simulated digestive tract model and mice model, in order to reveal the dose-effect and structure-activity relationship between structure and regulation of intestinal flora of the globulin treated by ultra-high pressure. Furthermore, the integration analysis among multi-omics technology, including metagenomics, signal pathway transcriptomics and metabonomics will be used, and then the further mechanism will be elucidated for gut flora regulation by the ultra-high pressure-treated buckwheat globulin, providing a theoretical foundation for benefit to health. This study will provide scientific basis for the development of high-quality buckwheat production with regulation of gut flora and for its quality control of ultra-high pressure.

肠道菌群结构的平衡与人体健康有着密切关系。我国独特资源荞麦所含球蛋白具有调节肠道菌群的活性功能，但该蛋白受热加工后其活性功能会降低，且其对肠道菌群结构两者间相互影响的作用机理尚未研究透彻。超高压作为非热加工的新技术，对食品风味以及热敏性活性物质影响较小，有着独特的优势与应用前景。本项目为提高荞麦球蛋白的活性功能和稳定性，将重点聚焦超高压处理对荞麦球蛋白调节肠道菌群结构的影响规律及机理。通过建立体外胃肠道消化模型与小鼠模型，明晰其类纤维素活性功能；并采用分子动力学的理论计算方法，解析超高压处理各技术参数与荞麦球蛋白结构及性质变化的规律，阐释超高压荞麦球蛋白结构与其类纤维素活性之间的量效与构效关系；通过多组学技术联用（宏基因组+代谢组+转录组），为揭示荞麦球蛋白调节肠道菌群结构，有益健康的机理奠定分子理论基础，为完善调节肠道菌群荞麦食品的超高压加工品质控制机理，开发高品质荞麦食品提供科学依据。

本项目针对荞麦13S球蛋白与降低胆固醇、抑制脂肪蓄积、抗氧化等独特功效间的构效关系不清晰，以及独特的生物活性稳定性差难于产业化的实际问题。以食品非热改性技术-UHP处理技术为切入点，不仅建立并优化了UHP处理荞麦13S球蛋白（BW13SG）的技术条件，并揭示了UHP处理能够改变BW13SG的羰基、巯基、二硫键、表面疏水性指数等结构表征，从而改善BW13SG蛋白疏水与水合性、乳化性、凝胶性等加工特性。同时，通过建立细胞氧化应激和脂代谢紊乱模型以及高脂膳食小鼠模型，从细胞水平和分子水平发现，超高压处理后BW13SG细胞存活率显著提升，并且超高压处理后BW13SG可显著降低厚壁菌门丰度，提高拟杆菌门的丰度，导致Escherichia-shigella增多，同时能够提高Bacteroidales、Blautia等产生短链脂肪酸菌群的丰富度。综合代谢组学、转录组学和肠道菌群结构分析可知，超高压处理后的荞麦13S球蛋白（BW13SG）能够降低小鼠血脂并提高机体抗氧化能力，增加胆酸排泄、降低脂肪与胆固醇吸收、提高肠道内短链脂肪酸含量，并可有效抑制炎性反应，从而干预脂代谢。最终揭示了超高压荞麦球蛋白对改变肠道菌群结构与其对脂类吸收代谢作用的内在关联的调控机制，为进一步发挥我国荞麦蛋白所独特的调节血脂活性功能奠定了重要的理论基础。