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Although sweet tea is rich in bioactive polysaccharides, the knowledge regarding their structures, bioactivities, and gut microbial metabolism is still limited. Therefore, in order to promote the application of sweet tea polysaccharide (STP) in the food industry, the pressurized hot water extraction (PHWE) of STP was optimized, and its structural properties and biological effects as well as microbial fermentation characteristics were investigated. The maximum extraction yield (4.64 % ± 0.03 %) of STP extracted by PHWE was obtained under the optimal conditions. Both homogalacturonan and arabinogalactan might exist as major polysaccharide fragments in STP. Additionally, STP exerted obviously in vitro antioxidant, anti-diabetic, and immunostimulatory effects, which might be related to its chemical properties, such as uronic acids, conjugated polyphenolics, and esterification degree. Furthermore, STP could be consumed by intestinal microbiota, and its fermentability was about 54 % at the end stage of fecal fermentation. Indeed, STP could modulate the microbial composition via improving the growth of several beneficial microbes, causing the release of beneficial short-chain fatty acids. Collectively, the findings indicate that the PHWE is an efficient method for extracting bioactive polysaccharides from sweet tea, and results can also provide a scientific basis for developing STP into functional foods or functional ingredients. • Pressurized hot water extraction of sweet tea polysaccharide (STP) was optimized. • STP was mainly composed of HG and AG fragments. • STP exerted multiple health-promoting effects in vitro. • The potential metabolic behavior of STP by gut microbiota was revealed. • STP could modulate the gut microbial composition to improve intestinal health. [ABSTRACT FROM AUTHOR]

This study assessed the potential prebiotic characteristics of the previously reported Lactiplantibacillus plantarum extracellular polysaccharide (EPS-T1) with immunological activity. EPS-T1 was a novel heteropolysaccharide composed of glucose and galactose (1.00:1.21), with a molecular weight of 1.41 × 106 Da. The monosaccharide composition, molecular weight, fourier transform infrared, and 1H NMR analysis showed that EPS-T1 was well tolerated in the simulated oral cavity, gastric fluid, and small intestinal fluid environments, and was not easily degraded. Meanwhile, EPS-T1 could effectively be used as a carbon source to promote the growth of beneficial Lactobacillus species (Lactobacillus delbrueckii ssp. Bulgaricus , Streptococcus thermophilus , Lacticaseibacillus rhamnose GG, Lactiplantibacillus plantarum , Lacticaseibacillus paracasei and Lactobacillus reuteri). After 24 h of fecal fermentation, EPS-T1(5 mg/mL) effectively reduced the relative abundance of harmful bacteria such as the Escherichia-Shigella , Citrobacter , Fusobacterium , Parasutterella , and Lachnoclostridium. While, the level content of beneficial flora (Bacteroides , Blautia , Phascolarctobacterium , Bifidobacterium , Parabacteroides , and Subdoligranulum) were significantly increased. In addition, EPS-T1 was able to significantly promote the enrichment of short-chain fatty acids such as acetic acid, propionic acid and butyric acid. These results provide some basis for the functional application of EPS-T1 as a potential prebiotic. [Display omitted] • EPS-T1 could be utilized as substrates for Lactobacillus growth. • EPS-T1positively regulated the structure and composition of gut microbiota. • EPS-T1 promotes the proliferation of Bifidobacterium spp. in the intestine • EPS-T1 reduces the abundance of pathogenic genera in the gut. • More SCFAs were produced with combination of EPS-T1. [ABSTRACT FROM AUTHOR]

This study aimed to explore the in vitro simulated digestion and fecal fermentation behaviors of two purified exopolysaccharide fractions (EPS1 and EPS2) from Paecilomyces cicadae TJJ1213 and its effects on human gut microbiota composition. Results showed that EPS1 and EPS2 could not be digested by saliva-gastrointestinal. After fecal fermentation, however, the molecular weight of EPS1 and EPS2 significantly decreased, and the molar ratios of the monosaccharide composition remarkably changed, indicating that EPS1 and EPS2 could be degraded and consumed by human gut microbiota. Notably, EPS1 and EPS2 could significantly modulate the composition, via increasing the relative abundances of Bacteroides and Phascolarctobacterium and decreasing the pathogenic bacteria Escherichia-Shigella, Klebsiella and Fusobacterium. In addition, EPS1 and EPS2 also could promote the production of short-chain fatty acids during fermentation for 24 h. These results suggested that EPS from Paecilomyces cicadae TJJ1213 can be used as a functional food to improve health and prevent diseases by promoting gut health. [Display omitted] • EPS1 and EPS2 from P. cicadae TJJ1213 was mainly composed of mannose and galactose. • EPS1 and EPS2 were not digested in stimulated saliva, gastric and intestinal conditions. • EPS1 and EPS2 were degraded and utilized by intestinal microbiota. • EPS fermentation promoted the production of short chain fatty acids. • EPS fermentation enhanced the relative abundances of beneficial bacteria. [ABSTRACT FROM AUTHOR]

Carboxymethyl chitosan and resistant starch exhibit good performance in diabetes regulation. We prepared carboxymethyl chitosan - resistant starch complex. Test the properties of composite resistant starch by using X-ray diffraction, water contact angle, infrared spectroscopy, and scanning electron microscopy, interactions with intestinal microbiota and mouse experiments were also conducted. The results indicated that the composite resistant starch had a good effect on promoting the proliferation of probiotics on Bifidobacterium and a significant inhibitory effect on Escherichia coli than resistant starch (P < 0.05). After administration, the water intake and weight of diabetic mice were significantly reduced. The blood glucose of diabetic mice was also reduced, and oral glucose tolerance showed that the glucose degradation rates of composite resistant starch were significantly improved compared to model mice. Cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein were significantly lower than those in the diabetes group (P < 0.05). The diversity of the gut microbiota was also proven. • Carboxymethyl chitosan can enhance the efficacy of resistant starch. • Carboxymethyl chitosan-resistant starch complex can adjust the gut flora better the resistant starch. • Carboxymethyl chitosan-resistant starch complex can improve the diabetes mice better the resistant starch. [ABSTRACT FROM AUTHOR]

Through previous study, the three yeast α-mannans (MPS) from various sources of Kluyveromyces marxianus (LZ-MPS, MC-MPS, and G-MPS) were preliminarily characterized. In this study, the advanced structural characterization and the in vitro human fecal fermentation behavior of the three MPS were investigated. According to the results of this study, the polysaccharide molecules of the three MPS were aggregated in solution, supporting their branched chain structure. After in vitro fermentation, the molecular weight and pH of fermentation broth decreased significantly, indicating that the three MPS could be utilized by human gut microbiota. Meanwhile, the production of total short-chain fatty acids (SCFAs) of the three MPS was promoted, especially the production of propionic acid was 45.55, 38.23, and 38.87 mM, respectively. In particular, the three MPS have the ability to alter the composition of human gut microbiota, especially to promote the proliferation of Bacteroidetes, suggesting that the bioactivities of the three MPS can be significantly influenced by intestine Bacteroidetes. In terms of metabolism, all MPS can promote cofactors, vitamins, amino acid metabolism, and glycan biosynthesis and metabolism of bacteria. In consequence, the three MPS were confirmed to regulate the human gut microbiota, increase the level of SCFAs, promote the metabolisms of bacteria on amino acid and glycan, and improve the intestinal health. [Display omitted] • The advanced structure of LZ-MPS, MC-MPS, and G-MPS were characterized. • The three MPS molecular exhibited aggregation due to the highly branched structure. • The three MPS improved the levels of total SCFAs. • Effects of the three MPS on gut microbiota were investigated. • The three MPS can enhance the metabolism of amino acids and glycan. [ABSTRACT FROM AUTHOR]