体外模拟柴达木大肥菇胞内多糖在幼龄肠道的消化特征

In vitro simulation of the digestive characteristics of Agaricusbitorquis (Quél.) Sacc. intracellular polysaccharides in the intestinal tract of children

该文以柴达木大肥菇胞内多糖(intercellular polysaccharides, IPS)为研究对象,借助3~5岁年龄段人群的肠道菌群构建体外肠道酵解模型,通过液相色谱法、气相色谱法和苯酚-硫酸法测定单糖及醛酸、短链脂肪酸的组分和含量变化以及总糖含量变化等指标探究IPS的体外酵解特征。结果显示,在体外酵解48 h过程中,胞内多糖不断被肠道菌群降解,在酵解12 h时酵解率已达100%;多糖降解产生葡萄糖、甘露糖、葡萄糖醛酸、半乳糖醛酸、阿拉伯糖5种单糖及醛酸,其总量随着酵解时间的延长呈先上升后下降趋势,在酵解6 h时达到含量最高峰,与对照组相比差异显著(P<0.05);单糖及醛酸被微生物群落进一步酵解后产生乙酸、丙酸、正丁酸、异丁酸、异戊酸及正戊酸6种短链脂肪酸,其总量随着酵解时间的延长呈持续上升趋势,与对照组相比差异显著(P<0.05);丰富的短链脂肪酸含量使发酵体系中的pH逐渐下降,最终稳定在3.56±0.01,与对照组相比差异显著(P<0.05)。综上,解析柴达木大肥菇IPS在肠道中的酵解、消化特性,可拓展柴达木大肥菇多糖开发为功能因子的营养健康内核。

Agaricusbitorquis(Quel.) Sacc. intracellular polysaccharide was used as the research object to construct its effect in children in vitro intestinal glycolysis model. The change in the pH value, monosaccharide and uronic acid, total sugar and short-chain fatty acids of polysaccharide fermentation products were respectively determined by potentiometric method, liquid chromatography, phenol-sulphuric acid assay and gas chromatography to explore the characteristics of IPS. The results showed that intracellular polysaccharides were continuously degraded by intestinal flora during 48 h of in vitro fermentation, and the hydrolysis rate reached 100% at 12 h of fermentation. Five monosaccharides and uronic acid(glucose, D-mannoose, glucuronic acid, galacturonic acid, arabinose) were produced by polysaccharide degradation, and the total amount of the monosaccharides increased firstly and then decreased with the increase of the fermentation time, and reached the highest content at 6 h of fermentation. This difference was significant compared with the control group(P<0.05). Then the monosaccharide and uronic acid were further fermented by the microbial community to produce six kinds of short-chain fatty acids, including acetic acid, propionic acid, n-butyric acid, isobutyric acid, iso-valeric acid and n-valeric acid. The total amount of these fatty acids showed a continuously increasing trend with the increase of the fermentation time, and the difference was significant compared with the control group(P<0.05). The abundance of short-chain fatty acids made pH value of the fermentation system decreased gradually and finally stabilized at 3.56(0.01, which was significantly different from that of the control group(P<0.05). To sum up, the analysis of the characteristics of intestinal fermentation and digestion of Agaricusbitorquis(Quel.) Sacc. intracellular polysaccharides in the intestine could expand the development of intracellular polysaccharides as a nutritional and healthy core of functional factors.