金花茶多糖的体外消化及酵解特性研究

龚雯; 唐婕; 韦雅渊; 宁恩创; 韦璐

doi:10.13386/j.issn1002-0306.2021040059

金花茶多糖的体外消化及酵解特性研究

In vitro Digestion and Fermentation Characteristics of Polysaccharides from Camellia nitidissima Chi

摘要

摘要: 采用水提醇沉法提取金花茶多糖，并通过DEAE-52纤维素柱层析对其分级纯化；通过模拟人体胃肠道消化模型对金花茶多糖进行体外消化，并检测消化过程中多糖分子量及消化产物中还原糖含量和游离单糖，探索金花茶多糖的消化特性；通过建立人体粪便酵解模型对金花茶多糖进行体外酵解，并测定酵解过程中酵解产物的pH、总糖和还原糖含量、SCFAs含量及乳酸杆菌、双歧杆菌、大肠杆菌的菌落总数，探索金花茶多糖的酵解特性。结果表明：金花茶多糖经DEAE-52纤维素柱层析纯化后，得到多糖级分TPS1、TPS2和TPS3。体外消化过程中，模拟唾液、模拟肠液没有改变TPS1、TPS2和TPS3的分子量，消化产物中还原糖含量也未见显著变化；而模拟胃液致使TPS1、TPS2和TPS3的分子质量略微降低，且还原糖含量由0.129±0.016、0.155±0.026、0.147±0.017 mmol/L增加为0.223±0.018、0.319±0.013、0.294±0.030 mmol/L；体外消化结束后未检测到游离单糖产生。体外酵解过程中，添加了TPS1、TPS2和TPS3的酵解液组的pH相较空白对照组均明显降低，总糖消耗率分别为91.4%、89.0%、94.5%，且还原糖含量在0~18 h期间升高，18~8 h期间降低；乙酸、丙酸、丁酸的浓度相较对照组都得到明显提升，增加倍数TPS3组>TPS2组>TPS1组；另外，TPS1、TPS2和TPS3均能够促进乳酸杆菌、双歧杆菌的增殖，并抑制大肠杆菌的生长，且益生效果TPS3>TPS2>TPS1。综上，金花茶多糖在体外消化模型中不易被消化，并能够被人体肠道菌群分解利用，产生大量乙酸、丙酸、丁酸等，具有潜在的益生作用，且TPS3较TPS2、TPS1具有更好的益生效果。

Abstract: Polysaccharides were isolated from Camellia nitidissima Chi by water extraction and alcohol precipitation, then the polysaccharide extract was separated and purified by using DEAE-52 cellulose chromatography column. The digestion characteristics of the polysaccharides were studied in vitro by employing a simulated upper gastrointestinal model and analyzing molecular weight, reducing sugar and free monosaccharide ontents of digested products at different digestion times. The fermentation characteristics of polysaccharides were studied in vitro by using human fecal fermentation model and analyzing pH, total sugar, reducing sugar and short chain fatty acid content, as well as the Lactobacillus, Bifidobacterium and Escherichia coli number. The results showed that, TPS1, TPS2, and TPS3 were obtained after purification of the polysaccharide from Camellia nitidissima Chi. During in vitro digestion, the molecular weight of TPS1, TPS2, TPS3 and the reducing sugar content did not changed by simulated saliva and simulated intestinal juice. Simulated gastric juice caused a slight decrease in the molecular weight of TPS1, TPS2, and TPS3, and the content of reducing sugar increased from 0.129±0.016, 0.155±0.026, 0.147±0.017 mmol/L to 0.223±0.018, 0.319±0.013, 0.294±0.030 mmol/L. Free monosaccharides were not detected during the digestion. During the fermentation process, the pH of the group added with TPS1, TPS2, and TPS3 was significantly lower than that of the blank control group, the sugar consumption rate was 91.4%, 89.0%, 94.5%, and the reducing sugar content increased during 0~18 h, reduced during 18~48 h. Compared with the blank control group, the levels of acetic acid, propionic acid, and butyric acid were all significantly increased and the order of increasing multiple size was TPS3>TPS2>TPS1. Further, TPS1, TPS2 and TPS3 could promote the growth of Lactobacillus and Bifidobacterium, inhibit the growth of Escherichia coli, and the order of probiotic effects was TPS3>TPS2>TPS1. In summary, the polysaccharides were isolated from Camellia nitidissima Chi were not digested in vitro, and could be used by fecal microflora to produce a large amount of acetic acid, propionic acid and butyric acid, which had potential probiotic effects. And TPS3 had better probiotic effects than TPS2 and TPS1.