不同热处理对全谷燕麦膳食纤维组分结构及其胃肠道健康效应的影响

Oats is a healthy whole grain rich in dietary fiber (DF). The whole grain dietary fiber structures are an important factor affecting the gastrointestinal health. Studies have shown that thermal processing can affect the characteristics and structures of the DF. However, the structural changes of the whole-grain oats DF with different thermal processing methods and its impact on the gastrointestinal health have not been studied systematically. This project use different thermal processing methods processing oats grain, employing high-performance liquid chromatography (HPLC), multi-angle light scattering, high performance anion exchange chromatography (HPAEC) with specific enzymatic hydrolysis and nuclear magnetic resonance (NMR) to study the effects of thermal processing on the molecular weight distribution, degree of polymerization and sugar chain structure changes of the whole-grain oats DF components; use atomic force microscopy (AFM) and scanning electron microscopy (SEC) to observe microstructure of the DF and further study the nature changes. On this basis, we compare the effects of whole-grain oats DF with different structures on gastric emptying, chyme viscosity, nutrient digestibility and degradation characteristics of colonic fermentation using enzymatic digestion in vitro simulating the upper gastrointestinal tract and continuous colonic fermentation model; focuses on the impacts of DF on the intestinal microflora and differences of metabolites produced in the colonic fermentation. The results will reveal the mechanism of thermal processing causing oats DF structural changes, express the relationship of DF structure and gastrointestinal healthy, and provide a theoretical basis for understanding the nutritional effects of whole-grain products.

燕麦是一种含有丰富膳食纤维（DF）的健康全谷，全谷物DF结构变化是影响胃肠道健康的重要因素。研究表明热加工会影响DF的结构及性质，但不同热加工方式下全谷燕麦膳食纤维的结构变化及其对胃肠道健康效应影响的研究较少。本项目以不同热加工方法处理燕麦全谷，采用高效液相色谱（HPLC）、特异性酶水解结合高效液相离子色谱法（HPAEC）、核磁共振（NMR）等方法研究热加工对燕麦DF组分的分子量分布、聚合度和糖链结构变化；并用扫描电镜（SEC）和原子力显微镜（AFM）等观察其形貌和构象；进一步研究DF的性质。在此基础上，采用体外模拟上消化道对食物酶促消化以及连续结肠发酵模型比较不同结构全谷燕麦DF对胃排空、食糜黏度、营养物质消化性及在结肠发酵降解特性的影响；重点研究DF对肠道菌群的影响和结肠发酵产生代谢产物的差异。研究成果将揭示热加工引起燕麦DF结构变化的机制，明确DF结构与胃肠道健康的关系。

燕麦是一种含有丰富膳食纤维（DF）的健康全谷，全谷物DF结构变化是影响胃肠道健康的重要因素。研究表明热加工会影响DF的结构及性质，但不同热加工方式下全谷燕麦DF的结构变化及其对胃肠道健康效应影响的研究较少。本项目以不同热加工方法处理全谷燕麦，分别得到了燕麦水溶性膳食纤维（SDF）、β-葡聚糖和戊聚糖；采用微波复合酶法制备得到燕麦抗性淀粉（即燕麦淀粉脂质复合物）；采用酸复合湿热方法制备得到燕麦抗性糊精。分别研究了这些不同燕麦DF组分的分子量分布、糖苷键变化以及微观形貌；进一步研究了热处理对DF组分溶解性、乳化性和对葡萄糖、胆酸钠等的吸附特性；在此基础上，采用体外模拟上消化道对食物酶促消化以及连续结肠发酵模型等方法比较了不同结构全谷燕麦DF组分在结肠发酵降解特性，重点揭示膳食纤维组分对不同条件益生菌存活的影响以及代谢的变化。阐明了热加工对燕麦DF结构功能影响与体内营养功效之间的内在联系，为燕麦功能性食品以及健康全谷物产品的研发提供了理论依据。

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