燕麦颗粒中谷粒态β-葡聚糖对淀粉消化以及糖脂代谢的影响

发布时间：2018-05-14 20:05

  本文选题：谷粒态β-葡聚糖 + 存在形式　； 参考：《江南大学》2016年硕士论文

【摘要】：流行病学和临床研究表明,全谷物燕麦的摄入会改善癌症、心血管疾病和糖尿病的症状,而这其中的膳食纤维β-葡聚糖发挥了主要作用,β-葡聚糖是葡萄糖单体通过(1,3)-(1,4)-β-糖苷键连接起来的非淀粉多糖。目前,绝大部分研究都以提取纯化的燕麦β-葡聚糖为研究对象,从其理化性质,比如粘度(分子量和浓度)来考虑其在降血糖,延缓淀粉消化等方面的功能,而以非提取的燕麦β-葡聚糖(保持β-葡聚糖在燕麦颗粒中原有的分布形式和存在状态,称为‘谷粒态’β-葡聚糖)为研究对象的报道比较鲜见。因此,本课题探究了提取的β-葡聚糖和燕麦粉中谷粒态β-葡聚糖对餐后血糖影响的差异以及机理,同时以高脂膳食所喂养的C57BL/6J小鼠为模型,探究两者对糖脂代谢影响的差异以及机理。本实验将燕麦粒磨粉、过筛,按照颗粒大小分级成了四种具有不同谷粒态β-葡聚糖含量的燕麦粉样品,颗粒越大含越多的谷粒态β-葡聚糖和蛋白质,并且两者的含量呈正相关。体外消化实验表明,燕麦粉中淀粉的消化速度随着颗粒的减小而增大;胃蛋白酶和β-葡聚糖酶预处理燕麦粉后,提高了淀粉的水解速度,但外加β-葡聚糖于消化体系时,对所提取纯化淀粉的消化特性无显著影响。燕麦粉糊化特性的研究表明糊化粘度值与颗粒大小呈正相关,且β-葡聚糖酶预处理燕麦粉后,其糊化衰减值以及最终粘度也显著下降。餐后血糖实验显示,大颗粒燕麦粉的餐后血糖曲线峰值比小颗粒燕麦粉的峰值更低,同时添加等量提取的β-葡聚糖到小颗粒燕麦粉体系中,其餐后血糖曲线的峰值与大颗粒燕麦粉的血糖峰值仍存在显著差异。推测燕麦粉中的蛋白质、β-葡聚糖可能对淀粉形成了一种物理包裹结构,降低了消化酶与淀粉的接触度,从而延缓了燕麦粉中淀粉的消化。采用高脂膳食喂养的C57BL/6J小鼠为模型,体内实验结果显示提取的β-葡聚糖和燕麦粉中谷粒态β-葡聚糖对小鼠的血糖、血脂、食欲调控都具有显著影响。β-葡聚糖提高了小鼠肝脏中GK活性,促进肝糖原合成;降低肝脏中G-6-Pase活性;降低了血液中TG和TC的含量以及OGTT曲线的GAUC;降低了GHbA1C含量。进一步的实验显示,β-葡聚糖可以促进小肠糖异生作用,进而提高胰岛素的敏感性,抑制了促进食欲的神经肽NPY的分泌,同时提高了抑制食欲的神经肽POMC的分泌。本文的创新点在于,从全谷物的角度出发,探究了燕麦颗粒(粉)中谷粒态β-葡聚糖的存在形式和结构;开发了一种以物理加工为基础的富集燕麦颗粒中β-葡聚糖的方法;并且首次从小肠糖异生的角度,探究了β-葡聚糖发挥有益生理功能可能的机理。
[Abstract]:Epidemiological and clinical studies have shown that whole-grain oats can improve symptoms of cancer, cardiovascular disease and diabetes. The dietary fiber 尾 -glucan plays a major role in this process. 尾 -glucan is a non-starch polysaccharide which is connected by a glucose monomer through the bond of 尾 -glucan and 尾 -glucan. At present, most of the studies focus on the extraction and purification of oat 尾 -glucan, and consider its function in lowering blood sugar and delaying starch digestion from its physical and chemical properties, such as viscosity (molecular weight and concentration). However, there are few reports on non-extracted oat 尾 -glucan (keeping the original distribution form and existing state of 尾 -glucan in oat granules, called 'grain state' 尾 -glucan). Therefore, the effects of 尾 -glucan and granulated 尾 -glucan on postprandial blood glucose in C57BL/6J mice fed with high fat diet were investigated. To explore the difference and mechanism of their effects on glucose and lipid metabolism. In this experiment, four kinds of oat flour samples with different grain 尾 -glucan content were classified into four kinds of oat flour samples with different grain size by grinding and sifting. The larger the grain size was, the more grain 尾 -glucan and protein were contained, and the two contents were positively correlated. In vitro digestion experiments showed that the digestion rate of starch in oat flour increased with the decrease of grain size, and that pepsin and 尾 -glucanase increased the hydrolysis rate of starch after pretreatment with pepsin and 尾 -glucanase, but when 尾 -glucan was added to the digestion system, There was no significant effect on the digestibility of the purified starch. The gelatinization properties of oat flour showed that the gelatinization viscosity was positively correlated with the particle size, and the gelatinization attenuation value and final viscosity of oat flour pretreated with 尾 -glucanase also decreased significantly. Postprandial blood glucose test showed that the peak of postprandial glucose curve of large granulated oat meal was lower than that of small granulated oat meal, and the same amount of 尾 -glucan was added to the small granulated oat meal system. There was still a significant difference between the peak of postprandial blood glucose curve and that of large granulated oat meal. It is speculated that the protein in oat meal, 尾 -glucan, may form a kind of physical encapsulation structure to starch, which reduces the contact degree between digestive enzyme and starch, thus delaying the digestion of starch in oat meal. C57BL/6J mice fed with high fat diet were used as the model. The results of in vivo experiments showed that the extracted 尾 -glucan and granulated 尾 -glucan in oat meal treated the blood glucose and blood lipid of mice. 尾 -glucan increased the activity of GK in liver of mice, promoted the synthesis of glycogen in liver, decreased the activity of G-6-Pase in liver, decreased the contents of TG and TC in blood and GAUCof OGTT curve, and decreased the content of GHbA1C. Further experiments showed that 尾 -glucan could promote the small intestinal glycosylation, thus increase insulin sensitivity, inhibit the secretion of appetite-promoting neuropeptide NPY, and increase the secretion of appetite-inhibiting neuropeptide POMC. The innovation of this paper is to explore the form and structure of 尾 -glucan in granulated oats from the point of view of whole grain, to develop a method of enriching 尾 -glucan in oat grains based on physical processing. From the point of view of small intestinal glycosylation, the possible mechanism of 尾-glucan's beneficial physiological function was explored for the first time.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R151
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本文编号：1889276