Effects of in vitro digestion and fecal fermentation on physico-chemical properties and metabolic behavior of polysaccharides from Clitocybe squamulosa

Functional Properties, Rheological Characteristics, Simulated Digestion, and Fermentation by Human Fecal Microbiota of Polysaccharide from Morchella importuna

Morchella importuna polysaccharide (MIP) has been proven to have obvious hypoglycemic effects on mice with type 2 diabetes (T2DM). This study looked at the functional and rheological characteristics of MIP, and investigated the effects of MIP on the human fecal microbiota through in vitro fermentation experiments. The outcomes demonstrate the excellent oil-holding capacity, emulsifying, foaming, and rheological characteristics of MIP. After salivary gastrointestinal digestion, the Mw of MIP decreased from 398.2 kDa and 21.5 kDa to 21.9 kDa and 11.7 kDa. By 16S rRNA sequencing of bacteria fermented in vitro, it was found that MIP did not improve the richness and diversity of intestinal microorganisms, but it may exert an anti-T2DM function by significantly increasing the relative abundance of Firmicutes and promoting Ruminococcaceae_UCG_014, Bacteroides, and Blautia proliferation. Escherichia-Shigella could also be inhibited to improve the intestinal microenvironment. In addition, the fermentation of MIP increased the total short-chain fatty acid (SCFA) concentration from 3.23 mmol/L to 39.12 mmol/L, and the propionic acid content increased significantly. In summary, MIP has excellent processing performance and is expected to exert potential anti-T2DM activity through the human intestinal microbiota, which has broad market prospects.

All-natural polysaccharide and protein complex nanoparticles from Clitocybe squamulosa as unique Pickering stabilizers for oil-in-water emulsions

This study aimed to develop novel nanoparticles that can serve as an excellent oil-in-water (O/W) Pickering stabilizer. The polysaccharide-protein complex nanoparticles (PPCNs-20 and PPCNs-40) were prepared at different ultrasonication amplitudes (20 % and 40 %, respectively) from the polysaccharide-protein complexes (PPCs) which were extracted from the residue of Clitocybe squamulose. Compared with PPCs and PPCNs-20, the PPCNs-40 exhibited dispersed blade and rod shape, smaller average size, and larger zeta potential, which indicated significant potential in O/W Pickering emulsion stabilizers. Subsequently, PPCNs-40 stabilized Pickering emulsions were characterized at different concentrations, pHs, and oil phase contents. The average size, micromorphology, rheological properties, and storage stability of the emulsions were improved as the concentration of PPCNs-40, the ratio of the soybean oil phase and pH value increased. Pickering emulsions showed the best stability when the concentration of PPCNs-40 was 3 wt%, and the soybean oil fraction was 30 % under both neutral and alkaline conditions. The emulsions demonstrated shear thinning and gelation behavior. These findings have implications for the use of eco-friendly nanoparticles as stabilizers for Pickering emulsions and provide strategies for increasing the added value of C. squamulosa.

In vitro digestion and fermentation behaviors of polysaccharides from Choerospondias axillaris fruit and its effect on human gut microbiota

Choerospondias axillaris fruit has attracted more and more attention due to its various pharmacological activities, which are rich in polysaccharides. This study investigated the in vitro saliva-gastrointestinal digestion and fecal fermentation behaviors of polysaccharides from Choerospondias axillaris fruit (CAP), as well as its impact on human gut microbiota. The results showed that CAP could be partially degraded during the gastrointestinal digestion. The FT-IR spectra of the digested CAP didn't change significantly, however, the morphological feature of SEM changed to disordered flocculent and rod-like structures. 16S rRNA sequencing analysis found that after in vitro fermentation, CAP could increase the relative abundances of beneficial bacteria including Megasphaera, Megamonas and Bifidobacterium to produce short-chain fatty acids (SCFAs), while it can also reduce the abundances of harmful bacteria of Collinsella, Gemmiger, Klebsiella and Citrobacter, suggesting that CAP could modulate the composition and abundance of gut microbiota. These results implied that CAP can be developed as a potential prebiotic in the future.

In vitro fermentation characteristics of polysaccharides from coix seed and its effects on the gut microbiota

Coix seed polysaccharides had received increasing attention due to their diverse biological activities. In this study, a homogeneous polysaccharide (CSPW) was extracted and purified from coix seed. Furthermore, the saliva-gastrointestinal digestion and fecal fermentation behavior of CSPW were simulated in vitro. The results showed that CSPW was mainly composed of glucose. It cannot be degraded by the simulated salivary and intestinal digestive system, but can be degraded by the simulated gastric digestive system. After fermentation for 24 h, CSPW promoted the production of short-chain fatty acids (SCFAs), with acetic acid, propionic acid and n-butyric acid being the main metabolites. In addition, CSPW could significantly regulate the composition and microbial diversity of gut microbiota by increasing the relative abundance of beneficial bacteria, such as Limosilicactobacillus, Bifidobacterium and Collinsella. Finally, further analysis of functional prediction revealed that amino acid metabolism, nucleotide metabolism and carbohydrate metabolism were the most important pathways for CSPW to promote health. In summary, our findings suggested that CSPW could potentially be used as a good source of prebiotics because it can be used by gut microbiota to produce SCFAs and regulate the gut microbiota.

In vitro digestion and fecal fermentation of basidiospore-derived exopolysaccharides from Naematelia aurantialba

Mushroom polysaccharides exhibit numerous health-enhancing attributes that are intricately linked to the breakdown, assimilation, and exploitation of polysaccharides within the organism. Naematelia aurantialba polysaccharides (NAPS-A), highly prized polysaccharides derived from mushrooms, remain shrouded in uncertainty regarding their characteristics pertaining to gastrointestinal digestion and gut microbial fermentation. The study aimed to understand the digestion and fecal fermentation patterns of NAPS-A. After simulated digestion, NAPS-A's physicochemical properties remained unchanged. However, during in vitro fecal fermentation, indigestible NAPS-A underwent significant changes in various properties, such as reducing sugar, chemical composition, constituent monosaccharides, Molecular weight, apparent viscosity, FT-IR spectra, and microscopic morphology. Notably, NAPS-A was effectively utilized by the gut microbiota, with unchanged properties after digestion but altered after fermentation. It influenced gut microbe composition by increasing beneficial bacteria (Lactobacillus, Faecalibacterium, and Roseburia), lowering pH, and producing short-chain fatty acids. NAPS-A fermentation enriches carbohydrate, fatty acid, and amino acid metabolic pathways through PICRUSt prediction analysis. Overall, these findings emphasize NAPS-A's role in regulating gut bacteria and their metabolic functions, despite its challenging digestibility.

Physicochemical properties of tiger nut (Cyperus esculentus L) polysaccharides and their interaction with proteins in beverages

This study aimed to extract tiger nut polysaccharides (TNPs) by the cellulase method which were graded using the DEAE-cellulose ion exchange method to obtain neutral (TNP-N) and acidic (TNP-A) polysaccharide classes. Analysis of the physical structures and monosaccharide compositions of TNP-A (3.458 KDa) and TNP-N (10.640 KDa) revealed lamellar and dense flocculent structures, with both primarily containing the monosaccharides glucose, galactose, and arabinose (Glc, Gal, and Ara). Single-factor and orthogonal tests were used to select three hydrocolloids, and the optimal ratio of the composite hydrocolloids was determined. Peanut protein drinks with a centrifugal sedimentation rate of 9.71% and a stability factor of 69.28% were obtained by adding 2.78% polysaccharide extract, 0.1% monoglyceride, and peanut pulp at a ratio of 1:15.5 g/mL. Polysaccharide protein drinks are more stable than commercially available protein drinks, with nutritional parameters either comparable to or better than those of the non-polysaccharide protein drinks.