Advances in the in vitro digestion and fermentation of polysaccharides

In vitro digestion models are widely used to study the structural changes, digestion and release of food components under simulated gastrointestinal conditions. As compared to the in vivo digestion tests, the in vitro digestion reflects the digestion and utilisation of food after ingestion and has the advantages of being time consuming, inexpensive, reproducible and free from moral and ethical restrictions. This study reviewed the current research studies on the in vitro simulated digestion of polysaccharides conducted in the last 5 years and focused on the oral, gastric and intestinal digestion models, with the aim of providing a basis for the further testing of changes in the content, structure and active ingredients of polysaccharides before and after digestion.     

功能性碳水化合物通过调节肠道菌群和代谢物改善非酒精性脂肪肝的作用机制

目的：探究双胞菇膳食纤维以及双胞菇粉对肠道菌群的调节功能。方法：通过水提醇沉的方法提取双胞菇膳食纤维和双胞菇粉末进行肠道微生物体外发酵,测定代谢产物中pH、产气量、短链脂肪酸的含量,采用IlluminaPE250测序平台对粪便微生物V4区进行富集测序,探究双胞菇膳食纤维和双胞菇粉对于肠道菌群中短链脂肪酸产生菌相对丰度的影响。结果：以低聚果糖为阳性对照组,不加膳食纤维为空白对照组,体外发酵过程中,随着时间的增加,双胞菇膳食纤维组pH从6.93下降到4.48,双胞菇粉末pH从6.93下降至4.86;随着时间的增加,与空白组相比,双胞菇膳食纤维组和双胞菇粉末组的产气量分别增加了3.4和1.9 mL;在体外发酵24 h后发现,与阳性对照组相比,双胞菇膳食纤维组和双胞菇粉末组的肠道菌群丰富度和多样性更高;双胞菇膳食纤维组和双胞菇粉末组均能被肠道微生物利用产生短链脂肪酸,与空白组相比,双胞菇膳食纤维组更有利于被肠道微生物利用产生乙酸（34.3 mmol/L）和丙酸（7.6 mmol/L）,促进有益菌属双歧杆菌属的生长,双胞菇粉末组更有利于产生乙酸（39.4 mmol/L）,促进肠杆菌属的生长;与阳性对照组相比,双胞菇膳食纤维组和双胞菇粉末组的丙酸产量更高。结论：双胞菇膳食纤维和双胞菇粉末均能被肠道菌群有效利用,产生短链脂肪酸,提高有益菌的相对丰度,与空白组相比,添加双胞菇膳食纤维的实验组效果最佳,对人体肠道菌群存在有效的益生调节功能。     

不同干燥方法对金针菇多糖抗氧化活性的影响

以金针菇为原料,利用传统水提法提取金针菇多糖（polysaccharides from Flammulina velutipes,FVP）,分别对传统热风干燥多糖（FVP-H）、真空干燥多糖（FVP-V）和冷冻干燥多糖（FVP-F）的成分和抗氧化活性进行研究。结果表明,FVP为酸性多糖,不同干燥方法对其单糖种类没有影响,但会改变单糖的构成比例和糖醛酸含量,FVP-H、FVP-V和FVP-F相对分子质量变化不明显,分别为2342309、2375843和2358437 Da。FVP-H、FVP-V和FVP-F具有较强的清除DPPH自由基、羟基自由基、超氧阴离子自由基的能力和还原力,在一定浓度范围内,多糖与抗氧化活性及还原能力之间呈正相关关系,干燥方法对FVP抗氧化活性具有不同的影响,其中FVP-F抗氧化活性最强,其次是FVP-V和FVP-H,冷冻干燥是制备FVP适宜的干燥方法。      

多糖、肠道微生物与免疫之间的相互影响

多糖具有免疫活性,也可调节肠道微生物菌群,而肠道微生物对宿主的多糖代谢与免疫功能起到重要作用,同时机体免疫又对肠道微生物产生影响。本文综述了多糖、肠道微生物与免疫之间相互影响的相关研究进展,为探究多糖、肠道微生物、免疫三者之间的内在关系及作用机理提供了参考。      

金针菇锌多糖分离纯化及其结构特征

目的：以金针菇为原料,经过逐步分离纯化得到两个锌多糖组分并研究其理化性质、光谱学特性及结构特征。方法：金针菇锌多糖采用热水浸提的方法提取,经DEAE纤维素-52和Sephadex G-100凝胶色谱柱逐步分离纯化后通过火焰原子吸收法测定多糖中锌的含量,高效凝胶过滤色谱法鉴定组分的均一性,并测定其分子质量及单糖组成,采用紫外光谱、红外光谱和刚果红实验对锌多糖的结构特征进行相关研究。结果：通过分离纯化得到两个锌多糖组分CF1、CF2,纯品提取率分别为20.97%与12.25%,其中锌含量分别为191、429 μg/g,平均分子质量分别为890、1 244 kD。CF1组分由葡萄糖、半乳糖等6 种单糖组成;CF2组分主要由甘露糖、葡萄糖、岩藻糖等8 种单糖组成,且两个多糖组分均具有三股螺旋分子结构。     

水浴法和微波法提取金针菇下脚料多糖的优化及比较研究

采用水浴法和微波辅助法对金针菇下脚料多糖的提取工艺进行了研究。实验结果表明,水浴料液比、提取温度和提取时间对金针菇下脚料多糖提取率有显著影响,优化的水浴提取工艺条件为料液比1:20,提取温度为80℃,提取时间2.0h,提取率达13.68%;微波提取料液比、微波功率和微波时间对金针菇下脚料多糖提取率有显著影响,优化的微波提取工艺为料液比为1:25,微波功率320W,微波提取时间80s,提取率达13.80%。与传统的水浴法相比,微波提取法效率高、节约能源,应用前景广阔。     

Effects of Flammulina velutipes polysaccharides on gut microbiota composition and metabolism in vitro fermentation

Food Science and Biotechnology - Flammulina velutipes polysaccharides (FVP) exhibit many biological activities, but the effects on gut microflora and metabolism were still unclear. Here, we...     

响应面法优化微波提取金针菇下脚料多糖的工艺

采用微波提取法对金针菇下脚料多糖的提取工艺进行研究。单因素和Box-Behnken设计试验结果表明,微波提取时间、液料比、微波功率对金针菇下脚料多糖提取率有显著影响;优化的提取工艺为微波提取时间85s、液料比23:1(mL/g)、微波功率320W,在此条件下提取率达13.12%。     

Metabolic and microbial modulation of phenolic compounds from raspberry leaf extract under in vitro digestion and fermentation

Raspberry leaves, by-products in raspberry production, are also a rich source of bioactive phytochemicals. In this study, the changes of phenolic compounds in raspberries leaf extract (RLE) under in vitro digestion and colonic fermentation were further studied by HPLC-MS analysis and 16S rRNA. The results showed that the phenolic compounds in RLE were relatively stable during in vitro gastric digestion; however, in the subsequent intestinal digestion and colonic fermentation, their content decreased sharply. A large amount of hydroxyphenylpropionic acid, hydroxyphenylacetic acid and urolithins were produced under the action of gut microbiota. Moreover, compared with corresponding control, RLE significantly reduced the ratio of Firmicutes/Bacteroidetes in all volunteers, increased the relative abundances of some beneficial bacteria, Enterococcus, Prevotella, and decreased the relative abundances of potential pathogens, Clostridium and Faecalibacterium. These findings suggest that RLE during in vitro digestion and fermentation has positive effects on gut microbiota and potential value of maintaining intestinal health.     

Physicochemical characterisation and α‐amylase inhibitory activity of tea polysaccharides under simulated salivary,gastric and intestinal conditions

Tea polysaccharides (TPS) are one of the main components of tea with various bioactivities. Digestion could result in the changes of the physicochemical properties and bioactivities of polysaccharides. The objective of this study was to determine the changes in physicochemical properties and α‐amylase inhibitory activities of TPS after simulated digestion. The structure of TPS determined by UV, IR and SEM showed that no obvious changes after salivary digestion, but significant changes after gastrointestinal digestion were observed. After intestinal digestion, the contents of reducing sugar were increased from 0.650 ± 0.011 to 1.594 ± 0.078 mm , and the centre molecular weight was decreased from 540.57 to 375.35 KDa. The molar ratio of monosaccharide was changed after digestion. And α‐amylase inhibition rate was significantly increased (P < 0.05). The results could provide information on the digestibility of TPSin vitro and contribute to the development of related functional foods or medicines.     

Beneficial effects of three brown seaweed polysaccharides on gut microbiota and their structural characteristics: An overview

The gut microbiota appears critical in the metabolic health and anti-disease activity. In this review, we discuss three brown seaweed polysaccharides (alginate, laminarin, fucoidan) for their structural information, the digestive behaviour and the effects on gut microbiota. Bioactivities are associated with various physicochemical properties, like solubility, viscosity, hydration properties, molecular weight, monosaccharide composition, and so on. Brown seaweed polysaccharides can be completely utilised by microbes in the large bowel, and they can regulate the gut microbiota. The ultimate metabolite of these polysaccharides is mainly short-chain fatty acids, which are able to regulate the ecology of the gut microbiota by increasing the growth of beneficial bacteria and inhibiting the growth of some harmful bacteria. In addition, this article also discusses the relationship between the structure and activity of modulating the gut microbiota. Results show that polysaccharides with low molecular weight are more conductive to modulate gut microbiota.     

超声辅助提取金针菇中麦角甾醇及其HPLC测定方法

采用超声辅助提取方法,通过单因素实验和正交实验,对影响麦角甾醇提取效果的主要因素提取溶剂、提取时间、料液比和提取温度进行研究,并建立金针菇中麦角甾醇HPLC测定方法。结果表明,各因素对金针菇中麦角甾醇得率的影响程度依次为提取次数、料液比、提取温度和提取时间。最佳提取条件为无水乙醇超声提取2次,每次20 min,料液比1∶50,提取温度50℃,在该提取条件下,麦角甾醇得率高达2.28 mg·g^-1。麦角甾醇的线性范围为10.00¹00.00μg·m L^-1,相关系数为0.9998,平均回收率（n=9）为100.31%,RSD（n=9）为2.69%,分析周期11 min。该法与传统皂化回流提取相比,提取效率及重现性均较好。      

Health effects of dietary sulfated polysaccharides from seafoods and their interaction with gut microbiota

Various dietary sulfated polysaccharides (SPs) have been isolated from seafoods, including edible seaweeds and marine animals, and their health effects such as antiobesity and anti-inflammatory activities have attracted remarkable interest. Sulfate groups have been shown to play important roles in the bioactivities of these polysaccharides. Recent in vitro and in vivo studies have suggested that the biological effects of dietary SPs are associated with the modulation of the gut microbiota. Dietary SPs could regulate the gut microbiota structure and, accordingly, affect the production of bioactive microbial metabolites. Because of their differential chemical structures, dietary SPs may specifically affect the growth of certain gut microbiota and associated metabolite production, which may contribute to variable health effects. This review summarizes the latest findings on the types and structural characteristics of SPs, the effects of different processing techniques on the structural characteristics and health effects of SPs, and the current understanding of the role of gut microbiota in the health effects of SPs. These findings might help in better understanding the mechanism of the health effects of SPs and provide a scientific basis for their application as functional food.     

发酵金针菇多酚的提取、纯化及抗油脂氧化能力研究

为探究发酵对金针菇多酚提取、纯化及抗油脂氧化能力的影响,以金针菇和发酵金针菇为原料,探讨以超临界CO2流体萃取法提取金针菇多酚的工艺条件,以及以柱层析法纯化多酚的工艺条件,并测定金针菇多酚(FVP)和发酵金针菇多酚(FFVP)的抗油脂氧化能力.结果 表明:金针菇多酚的最佳提取条件为萃取时间140 min、萃取压力30 ...     

肠道微生物体外发酵模型研究进展及其在食品中的应用

随着分子微生态学,特别是高通量测序技术的快速发展,人们对肠道微生物的作用有了进一步认识。肠道不仅是消化吸收的场所,其微生物菌群现更被认为是一个高度特异化的\     

蚕蛹蛋白和蚕蛹短肽的模拟胃肠道消化特性研究

研究了蚕蛹蛋白和蚕蛹短肽的氨基酸组成,并分析了其在模拟胃肠道消化过程中的消化特性和氮释放量,探究蚕蛹蛋白和短肽在人类营养支持方面的应用。使用自动氨基酸分析仪测定蚕蛹蛋白和蚕蛹短肽的氨基酸含量,并计算氨基酸评分(AAS)、化学评分(CS)和必需氨基酸指数(EAAI)。蚕蛹蛋白和蚕蛹短肽的消化特性和氮释放量通过体外模拟胃肠道消化实验和凯氏定氮法进行评价的计算。结果表明,蚕蛹蛋白和蚕蛹短肽含有人体所需的18种氨基酸,而且必需氨基酸的组成合理。蚕蛹蛋白和蚕蛹短肽在体外模拟胃肠道消化实验中有良好高效的消化率和较高的氮释放量(约90%)。因此在今后将蚕蛹蛋白和蚕蛹短肽作为优质且经济的蛋白质原料,在动物饲料和人类肠内营养支持制剂方面有巨大的应用潜力。      

Solvent extraction and in vitro simulated gastrointestinal digestion of phenolic compounds from purple sweet potato

The total content of phenolic compounds in purple sweet potato (PSP) was determined and the release of such compounds from PSP in gastrointestinal digestion was studied in vitro. The extraction conditions for the maximum recovery of free phenol (FP) and bound phenol (BP) from PSP were determined by response surface methodology (RSM). The maximum recovery of FPPSP was 14.16 ± 0.87 mg GAE per g short for dry weight (DW), which was obtained using 60% (v/v) ethanol maceration with a liquid–solid ratio of 57.21:1 (mL g⁻¹) at 51.93 °C for 2.12 h. The maximum recovery for BPPSP was 7.54 mg GAE per g DW, which was obtained upon hydrolysis with 1.87 mol L⁻¹ NaOH at a liquid–solid ratio of 35.93:1 (mL g⁻¹) for 4.74 h. The maximum phenolic content was released after 1 and 2 h for the in vitro gastric and intestinal digestion respectively. The release of the phenolics was promoted by pepsin and gastric acid during gastric digestion, while it was further promoted by trypsin during intestinal digestion.     

发酵金针菇菇根多糖提取、结构及抗氧化活性

为探究发酵对金针菇菇根多糖提取、结构及抗氧化活性的影响,首先将金针菇菇根进行固态厌氧发酵,然后分别提取普通菇根和发酵菇根的多糖,研究pH值、超高压压力和超高压时间对得率的影响,并用响应面法优化,最后分析2种多糖的结构及抗氧化活性.结果 表明,发酵使金针菇菇根多糖提取得率提高9.13％;相比普通菇根多糖,发酵菇根多糖呈板...     

Influence of fermentation with different lactic acid bacteria and in vitro digestion on the change of phenolic compounds in fermented kiwifruit pulps

The present study aimed to evaluate the effect of fermentation and gastrointestinal digestion of three kinds of fermented kiwifruit pulps with different Lactobacillus (Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus casei). The changes in bioactive substances (total phenolic acid, total flavonoid, vitamin C and the viable count), antioxidant capacity (DPPH, ABTS, hydroxyl radical and superoxide anion radical scavenging activity) and phenolic profiles (protocatechuic acid, protocatechualdehyde, chlorogenic acid, caffeic acid and p-coumaric acid) were detected. The result showed, compared to non-fermented kiwifruit pulp, fermentation with LP and LA had higher content of TPA, TF and V_C, as well as antioxidant capacity. Fermentation with LP and the content of protocatechualdehyde, p-coumaric acid and chlorogenic acid were increased. However, after digestion, LP showed more effect in maintaining the content of antioxidants, antioxidant capacity and the viable count rather than LA. During digestion, the content of protocatechualdehyde and p-coumaric acid was increased in fermented samples compared with non-fermented samples. Overall, compared with LA and LC, LP is more suitable for the fermentation of kiwifruit pulp.