Velutipes Polysaccharides Research Articles

Modulation of gut microbiota and metabolites by Flammulina velutipes polysaccharides during in vitro human fecal fermentation: Unveiling Bacteroides as a potential primary degrader

Flammulina velutipes, a widely cultivated species of edible fungus, exhibits diverse functional activities attributed to its polysaccharides. In this study, we employed an in vitro model to investigate the impact of F. velutipes polysaccharides (FVP) fermentation on gut microbiota, with a particular focus on Bacteroides. FVP fermentation resulted in the proliferation of microbiota associated with short-chain fatty acid (SCFA) metabolism and suppression of Escherichia-Shigella. Bacteroides emerged as potential primary degraders of FVP, with species-level analysis identifying the preference of B. thetaiotaomicron and B. intestinalis in FVP degradation. Metabolomics analysis revealed significant increases in hypoxanthine and 7-methyladenine contents, with histidine metabolism emerging as the most enriched pathway. B. nordii and B. xylanisolvens exhibited the most influence on amino acid and SCFA metabolism. Understanding the mechanisms by which gut microbiota metabolize FVP can provide valuable insights into the potential of FVP to promote intestinal health and disease prevention.

Effect of two different Flammulina velutipes polysaccharides on the physicochemical and digestive properties of rice starch and their interaction mechanisms

This study investigated the interaction mechanisms between rice starch (RS) and two different Flammulina velutipes polysaccharides (FPs) obtained through water-extracted (WEFP) and alkali-extracted (AEFP) methods regarding the pasting, gelatinization, retrogradation, and in vitro digestive properties. The WEFP, with a majority of α-glucan and lower MW, and the AEFP, a high MW trihelix β-glucan, distinctly affected the physicochemical and digestive properties of RS in a dose-dependent manner. Both FPs reduced the leached amylose content, retrogradation, and digestibility of RS, and increased the shear stress, storage modulus, and loss modulus of RS. The swelling power and pasting viscosities of RS were inhibited by WEFP and enhanced with AEFP. Compared with the control RS gel, WEFP increased the gelatinization temperatures while AEFP accelerated the gelatinization of RS. Fourier-transform infrared analysis revealed WEFP enhanced the hydrogen bonding with starch and water molecules which increased the short-range ordered structures, and a more compact, wrinkle, and ordered network structures could be visualized in RS-WEFP gel, which attributed to the decreased glycemic responses of RS-WEFP gels. However, reduced hydrogen bonds were observed in RS-AEFP systems, and entanglement effect of viscous AEFP on starch granules resulted a thicker and more disordered RS-AEFP gel structure, which was the main factor restricted the digestion rates of RS. This study provides a theoretical insight about the application of FPs on RS-based hypoglycemic foods.

Effects of Flammulina velutipes polysaccharide with ice recrystallization inhibition activity on the quality of beef patties during freeze-thaw cycles: An emphasis on water status and distribution

The antifreeze activity of Flammulina velutipes polysaccharide (FVP) autoclave-extracted with dilute alkaline and effects of FVP on moisture status, size of ice crystals, physical and chemical characteristics of beef patties during repeated freeze-thaw (F-T) cycles were investigated. Results showed that FVP exhibited ice recrystallization inhibition activity and was able to alter the onset freezing/melting temperature of beef patties. 0.01% FVP significantly alleviated (P < 0.05) the decrement in water holding capacity by inhibiting water migration, restraining the mobility of water, and reducing the size of ice crystals of beef patties during the repeated F-T cycles. In addition, FVP could effectively inhibited oxidation reaction and protein aggregation of beef patties with significant decreases in TBARS value, protein turbidity, contents of total sulfhydryl and carbonyl of myofibrillar protein, and an increase in protein solubility during the repeated cycles. These results suggest FVP could be developed to be a promising cryoprotectant in frozen patties.

Study on the physicochemical properties and antioxidant activities of Flammulina velutipes polysaccharide under controllable ultrasonic degradation based on artificial neural network

The polysaccharide fraction (FVP2) with molecular weight of 1525.09 kDa and intrinsic viscosity of 3.43 dL/g was isolated and purified from Flammulina velutipes (F. velutipes), and the ultrasonic degradation model of FVP2 was established to predict the molecular weight and intrinsic viscosity at the same time based on artificial neural network. FVP2U1 (1149.11 kDa, 1.78 dL/g), FVP2U2 (618.91 kDa, 1.19 dL/g) and FVP2U3 (597.35 kDa, 0.48 dL/g) with different molecular weights or viscosity were produced by this model to explore the effect of ultrasound on the physicochemical properties and antioxidant activity of FVP2. The results showed that ultrasonic treatment did not change the types of characteristic functional groups, monosaccharide composition and glycosidic bond of FVP2, but changed the chemical composition ratio and the degree of polymerization. Under ultrasonic treatment, the intrinsic viscosity of FVP2 still decreased significantly when the molecular weight did not decrease. Compared to other components subjected to ultrasonic degradation, FVP2U1 demonstrated higher molecular weight and viscoelasticity, while exhibiting lower antioxidant activity. In the case of no significant difference in molecular weight and monosaccharide composition, FVP2U3 with lower intrinsic viscosity has stronger hydration ability, higher crystallization index, lower viscoelasticity and stronger antioxidant capacity than FVP2U2.

Structure and immunostimulatory activity studies on two novel Flammulina velutipes polysaccharides: revealing potential impacts of →6)-α-D-Glcp(1→ on the TLR-4/MyD88/NF-κB pathway.

Two novel Flammulina velutipes (F. velutipes) polysaccharides, FVPH1 and FVPH2, were isolated and purified after hot water extraction. The structural characterization revealed that the backbone of FVPH1 consisted mainly of →6)-α-D-Glcp(1→, →3,4)-α-D-Galp(1→, →4)-α-L-Fucp(1→, and →4)-β-D-Manp(1→, while the backbone of FVPH2 consisted of →3)-α-D-Galp(1→, →3,4)-α-D-Manp(1→,→6)-α-D-Glcp(1→. The branches of FVPH1 contained →6)-α-D-Glcp(1→ and α-D-Glcp(1→ and the branches of FVPH2 consisted of →3)-α-D-Galp(1→, →6)-α-D-Glcp(1→, and β-L-Fucp(1→. FVPH2 exhibited significantly better immunostimulatory activity than FVPH1 (P < 0.05), as evidenced by the increased expression of NO, IL-1β, IL-6, and TNF-α and pinocytic activity of RAW264.7 cells. As the most abundant structure in the polysaccharides of F. velutipes, the content of →6)-α-D-Glcp(1→ might play a crucial role in influencing the immunostimulatory activity of F. velutipes polysaccharides. The F. velutipes polysaccharide with a lower content of →6)-α-D-Glcp(1→ and a higher branching degree could significantly enhance the immunostimulatory activity of F. velutipes polysaccharides via activating the TLR-4/MyD88/NF-κB pathway more effectively.

Flammulina velutipes polysaccharides regulate lipid metabolism disorders in HFD-fed mice via bile acids metabolism

Our recent study demonstrated that the dynamic changes of gut microbiota mediated by Flammulina velutipes polysaccharide (FVP) could effectively regulate the lipid metabolism in high fat diet-fed (HFD-fed) obese mice model. In this paper, further research was carried out by examining the bile acid (BAs) profiles, as well as the BAs metabolic pathways changes in obese mice. Furthermore, the regulatory effect of BAs on lipid metabolism was verified by 3 T3-L1 preadipocyte differentiation model. The FVP administration resulted in lower BAs content in plasma of obese mice. From the qRT-PCR analysis, FVP could relieve cholestasis in obese mice through altering the BAs metabolic pathways, changing the related genes expressions in mice liver and ileum. The cholic acid (CA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA) and ursodeoxycholic acid (UDCA) were selected in cell experiment which all reduced the intracellular triglyceride content and increased the expression of AMPKα1 in 3 T3-L1 adipocytes. Furthermore, CA and CDCA were found increased the expression of PPARα. In combination with our previous research, we further confirmed in this paper that the changes of BAs metabolism caused by FVP showed a positive effect on lipid metabolism, both in obese mice and 3 T3-L1 adipocytes.

Effect of ultrasonic modification on the protective activity of Flammulina velutipes polysaccharide to prevent ethanol-induced injury on GES-1 cells

Flammulina velutipes (F. velutipes) polysaccharides were modified by ultrasound at the rated power of 150 W and 900 W. The monosaccharide composition, ultraviolet-visible, and Fourier transform infrared spectral characteristics of F. velutipes polysaccharides (FVP) and their ultrasonic modification products (U-FVPs) were determined. The protective effects of FVP and U-FVPs on human gastric mucosal cells GES-1 were confirmed for the first time. The mole ratios of glucose and galactose were decreased and the mole ratio of mannose was increased after ultrasonic modification. Compared with the original FVP and the FVP modified by ultrasound of 150 W (U-FVP1), the FVP modified by ultrasound of 900 W (U-FVP2) could better prevent ethanol-induced damage to GES-1 cells. With increasing ultrasound intensity, the protective effect of FVPs on GES-1 cells was significantly enhanced by more effective prevention of intracellular reactive oxygen species (ROS) production and more promotion of expression of triglyceride factor 2 (TFF2), prostaglandin E2 (PGE2), epidermal growth factor (EGF), and transforming growth factor β1 (TGF-β1) mRNA. The ultrasonic modification might be an effective way to develop novel F. velutipes polysaccharides that could effectively resist the gastric injury caused by excessive alcohol consumption.

Flammulina velutipes polysaccharide counteracts cadmium-induced gut injury in mice via modulating gut inflammation, gut microbiota and intestinal barrier

Cadmium (Cd), as Group I carcinogen, can induce damage to various organs including the gut. It is of great importance to meet the rising demand for effective therapies against Cd-induced damage and investigate the mechanism. Flammulina velutipes is a popular edible mushroom, despite the well-known health benefits of Flammulina velutipes, little is known about the effect of its polysaccharide (FVP) against CdCl2-intestinal injury. In this study, a FVP (uronic acid, 5.10 %; degree of methylation, 41.24 %) was produced via hot water extraction (85 °C) and ethanol precipitation. The FVP contained eight major monosaccharides and exhibited good thermal stability at temperatures lower than 139.73 °C. FVP (100 mg/kg b. w., gavage for 4 weeks) alleviated CdCl2 (1.5 mg/kg b. w., gavage for 4 weeks)-induced intestinal inflammation and apoptosis, intestinal permeability alteration and intestinal barrier disruption. FVP increased the abundance of Bacteroides, whilst decreasing the abundance of Desulfovibrionales and Clostridium. FVP also restored the levels of short-chain fatty acids (SCFAs), including acetic, propionic, isobutyric, butyric, isovaleric and valeric acids. Correlation analysis indicated the interplays among the FVP, gut microbes, SCFAs, intestinal barrier/cells and gut inflammation. FVP enhances the metabolic functions of gut microbiota via functional pathways analyzed by KEGG database. Furthermore, gut microbial transplantation of FVP + CdCl2 group mice partially alleviated CdCl2 caused-gut damage. Thus, FVP may be an effective therapeutic agent against CdCl2-induced gut damage via SCFA-mediated regulation of intestinal inflammation and gut microbiota-related energy metabolism. This study may open a new avenue for developing alternative strategies to prevent CdCl2-caused injury.

Effect of Flammulina velutipes polysaccharides on endoplasmic reticulum stress-mediated apoptosis by activating PLC-IP3 pathway in HepG2 cells.

Flammulina velutipes polysaccharides (FVP) have been proven to induce apoptosis in HepG2 cells. It is well known that endoplasmic reticulum stress (ERS) is involved in apoptosis. However, ERS mediates FVP-induced apoptosis in HepG2 cells remains unclear. In our study, the results indicated that FVP caused ERS in HepG2 cells. They showed that FVP were water-soluble polysaccharides with the weight average molecular weight of 1972kDa, which were mainly composed of mannose, gluconic acid, glucose, galactose, xylose and fructose in a molar ratio of 6.6 : 1.3 : 79.9 : 7.4 : 3.4 : 1.5. After FVP treatment, the expression levels of genes and proteins related to ERS were upregulated. The inhibition of ERS by 4-phenylbutyric acid (4-PBA) pretreatment could significantly reduce the role of FVP in inducing apoptosis. We further found the results of immunofluorescence and flow cytometry showing that Ca2+ in the ERS leaked out, and the intracellular Ca2+ concentration increased after FVP treatment. The pretreatment with the phospholipase C (PLC) inhibitor U73122 proved that FVP caused excessive intracellular Ca2+ concentration by activating the phospholipase C-inositol-1,4,5-triphosphate (PLC-IP3) pathway, resulting in ERS, and ultimately leading to apoptosis. In summary, our results indicated that FVP induced ERS-mediated apoptosis by activating PLC-IP3 pathway in HepG2 cells. PRACTICAL APPLICATION: This work may suggest that FVP could be used as an adjuvant therapy to anticancer drugs, providing new application prospects and possibilities.

3D printing properties of Flammulina velutipes polysaccharide-soy protein complex hydrogels

Food 3D printing targets special consumers, such as children, elderly individuals and patients. For food 3D printing, soy protein isolate hydrogels are widely used but have obstacles in hydrogel reshaping. To improve the physical properties of the hydrogel for 3D printing, soy protein isolate can form composites with other hydrocolloids, such as Flammulina velutipes polysaccharide. Therefore, we evaluated the 3D printing accuracy and stability of the composite between soy protein isolate and Flammulina velutipes polysaccharide. The hydrogel of the composite with thermal treatment after 3D printing was accurate (>99.7%) and stable (>99.9%). Adding Flammulina velutipes polysaccharide and thermal treatment made the hydrogel less viscous and stronger, with a more uniform and denser microstructure. Thermal denaturing soy protein and introducing –OH from Flammulina velutipes polysaccharide to enhance β-sheets were the likely reasons for the improved hydrogel characteristics. Our findings suggested that adding Flammulina velutipes polysaccharide and thermal treatment could improve food 3D printing. • • Flammulina velutipes polysaccharide (FVP) improved the 3D printability of soy protein. • • Heated FVP and soy protein isolate (h-FVP-SPI) showed high accuracy via 3D printing. • • More β-sheets in h-FVP-SPI leaded to increased G′ and better stability. • • Strong networks of h-FVP-SPI leaded to a uniform surface and low free water.

Prevention of quality characteristic decline in freeze-thawed cultured large yellow croaker (Larimichthys crocea) using flammulina velutipes polysaccharide.

To investigate the cryoprotective effect of flammulina velutipes polysaccharide (FVP) on the quality characteristics in freeze-thawed cultured large yellow croaker, 0.050%, 0.075%, and 0.100% FVP was used before freezing and the quality after thawing was compared with water soaking (WS) and commercial cryoprotectant (CC) treatment. Quality attributes were comprehensively determined instrumentally and organoleptically after thawing at 4°C. Results showed that FVP effectively reduces the quality deterioration of body color and water-holding capacity, while no obvious effects were observed in texture and flavor. As for body color, both FVP and CC treatment could maintain the b* value to a large extent. Among them, 0.075% FVP shows the highest value in two sample points, with 55.2% and 21.0% increases seen in the values in WS. FVP-dose-dependent trends were found in water-holding capacity, where a reduction of 28.26% and 14.38% in thawing loss and cooking loss was observed in the 0.100% FVP group. Low-field nuclear magnetic resonance (LF-NMR) also revealed that immobilized water and free water were more tightly retained in the muscle tissue with FVP addition. The results of the sensory evaluation are essentially in line with the above observations. These findings indicate that FVP has the potential to partially replace commercial cryoprotectants in aquatic products during frozen storage.

Flammulina velutipes polysaccharide improves the water-holding capacity in the dorsal muscle of freeze-thawed cultured large yellow croaker (Larimichthys crocea)

To investigate the effect of Flammulina velutipes polysaccharide (FVP) on the water-holding capacity (WHC) in the dorsal muscle of freeze-thawed large yellow croaker, fresh fish were treated with FVP, commercial cryoprotectant (CC), and distilled water before freezing. The water-holding capacity (WHC) and related influencing factors were analyzed. The results showed that FVP was able to effectively improve the WHC by reducing thawing loss and cooking loss, and the effect was similar to that of the CC group. Smaller and rounder ice crystals and less damaged muscle tissue were observed in FVPs. FVP also significantly retarded the protein denaturation revealed by Ca2+-ATPase activity, ultraviolet–visible absorption spectra, and SDS-PAGE of the myofibrillar protein. Furthermore, protein oxidation was inhibited by FVP treatment, as demonstrated by the sulfhydryl group and intrinsic fluorescence intensity. In summary, FVP can effectively improve the WHC by inhibiting the growth of ice crystals, protein denaturation, and potentially protein oxidation.

Effect of ionic strength and mixing ratio on complex coacervation of soy protein isolate/Flammulina velutipes polysaccharide

Soy protein isolate (SPI) is a commercial protein with balanced amino acids, while the poor solubility impedes its use in traditional foods. To overcome the problem, the complex coacervation of SPI/Flammulina velutipes polysaccharide (FVP) were investigated. Initial results revealed that the suitable amounts of FVP contributed to reducing the turbidity of SPI solution. Under electrostatic interaction, the formation of SPI/FVP coacervates were spontaneous and went through a nucleation and growth process. Low salt concentration (CNaCl = 10, 50 mmol/L) led to an increase in the critical pH values (pHc, pHφ1) while the critical pH values decreased when CNaCl ≥ 100 mmol/L. The concentration of NaCl ions increased the content of α-helix. With the increase of FVP, the critical pH values decreased and the content of β-sheet increased through electrostatic interaction. At SPI/FVP ratio of 10:1 and 15:1, the complex coacervation of SPI/FVP were saturated, and the coacervates had the same storage modulus value. SPI/FVP coacervates exhibited solid-like properties and presented the strongest storage modulus at CNaCl = 50 mmol/L. The optimal pH, SPI/FVP ratio and NaCl concentration of complex coacervation were collected, and the coacervates demonstrated a valuable application potential to protect and deliver bioactives and food ingredients.

The Effect of Flammulina velutipes Polysaccharide on Immunization Analyzed by Intestinal Flora and Proteomics

Proteomics and intestinal flora were used to determine the mechanism of immune modulatory effects of Flammulina velutipes polysaccharide on immunosuppressed mice. The results showed that compared with the model group, F. velutipes polysaccharide could increase thymus and spleen indices and improve thymus tissue structure in mice; IL-2 and IL-4 contents were significantly increased and IL-6 and TNF-α contents were significantly decreased; serum acid phosphatase (ACP), lactate dehydrogenase (LDH) and total antioxidant capacity (T-AOC) activities were increased (P < 0.05); in the liver, superoxide dismutase (SOD) and catalase (CAT) activities were increased (P < 0.001), while malondialdehyde (MDA) content was decreased (P < 0.001). Proteomics discovered that F. velutipes polysaccharides may exert immune modulatory effects by participating in signaling pathways such as immune diseases, transport and catabolism, phagosomes and influenza A, regulating the immune-related proteins Transferrin receptor protein 1 (TFRC) and Radical S-adenosyl methionine domain-containing protein 2 (RSAD2), etc. Gut microbial studies showed that F. velutipes polysaccharides could increase the abundance of intestinal flora and improve the flora structure. Compared to the model group, the content of short-chain fatty acids (SCFAs) and the relative abundance of SCFA-producers Bacteroides and Alloprevotella were increased in the F. velutipes polysaccharide administration group, while Lachnospiraceae_NK4A136_group and f_Lachnospiraceae_Unclassified decreased in relative abundance. Thus, F. velutipes polysaccharide may play an immunomodulatory role by regulating the intestinal environment and improving the balance of flora.

Effects of ultrasound on the degradation kinetics, physicochemical properties and prebiotic activity of Flammulina velutipes polysaccharide

The controllable ultrasonic modification was hindered due to the uncertainty of the relationship between ultrasonic parameters and polysaccharide quality. In this study, the ultrasonic degradation process was established with kinetics. The physicochemical properties and prebiotic activity of ultrasonic degraded Flammulina velutipes polysaccharides (U-FVPs) were investigated. The results showed that the ultrasonic degradation kinetic models were fitted to 1/Mt-1/M0 = kt. When the ultrasonic intensity increased from 531 to 3185 W/cm2, the degradation proceeded faster. The decrease of polysaccharide concentration contributed to the degradation of FVP, and the fastest degradation rate was at 60 °C. Ultrasound changed the solution conformation of FVP, and partially destroyed the stability of the triple helix structure of FVP. Additionally, the viscosity and gel strength of FVP decreased, but its thermal stability was improved by ultrasound. Higher ultrasonic intensity led to larger variations in physicochemical properties. Compared with FVP, U-FVPs could be more easily utilized by gut microbiota. U-FVPs displayed better prebiotic activity by promoting the growth of Bifidobacterium and Brautella and inhibiting the growth of harmful bacteria. Ultrasound could be effectively applied to the degradation of FVP to improve its physicochemical properties and bioactivities.

Effects of Flammulina velutipes polysaccharides on quality improvement of fermented milk and antihyperlipidemic on streptozotocin-induced mice

Flammulina velutipes polysaccharide (FVP) has become a focus of attention due to its extensive physiological activity, and the addition of polysaccharides to probiotic fermented milk is a hot research topic in functional dairy products in recent years. In the present work, the physicochemical property and bioactivities of fermented milk contained with FVP isolated from fruiting body were evaluated. Our results indicated that fermented milk contained with FVP had better qualities and sensory scores. Moreover, in vivo data manifested that fermented milk contained with FVP could ameliorate hyperglycemia against diabetes by reducing blood glucose and insulin levels, and regulating dyslipidemia and the disorder of glycometabolism via the PI3K/Akt signaling pathway. Taken together, the study demonstrated that fermented milk contained with F. velutipes polysaccharides might be bioactive compounds for diabetes prevention, providing the basic theory for developing novel fermented drinks.

The biological regulatory activities of Flammulina velutipes polysaccharide in mice intestinal microbiota, immune repertoire and heart transcriptome

The effects of a novel Flammulina velutipes polysaccharide (FVP) on intestinal microbiota, immune repertoire and heart transcriptome were investigated in this study. The results showed that FVP treatment could effectively regulate the abundance of colonic microbiota. And FVP exhibited obvious immunoregulatory effect by influencing V gene and J gene fragments usage on TCRα chain. The usage frequency of TRBV1, TRBJ1-6 and TRBJ1-5 were significantly altered, and 41 V-J pairs were identified with obvious difference after FVP treatment. Furthermore, the mRNA of mice heart was analyzed by transcriptome assay. Total 525 genes and 1587 mRNA were significantly changed after FVP treatment. KEGG annotation indicated that the up-regulated mRNA was enriched in 17 pathways including adherens junction, mTOR signaling pathway, insulin signaling pathway, mitophagy, tight junction, PPAR signaling pathway and TNF signaling pathway, etc. Meanwhile, the down-regulated mRNA was gathered in AMPK signaling pathway, metabolism of xenobiotics by cytochrome P450, apelin signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, insulin signaling pathway, cardiac muscle contraction, adrenergic signaling in cardiomyocytes, Fc gamma R-mediated phagocytosis, etc. The great potential exhibited by FVP could make it an ideal candidate as complementary medicine or functional food for promotion of health.

Characterization of soy protein isolate/Flammulina velutipes polysaccharide hydrogel and its immunostimulatory effects on RAW264.7 cells

Soy protein isolate (SPI) is a nutritional commercial product, while the poor solubility and gelling restricts its applications for functional foods. To surmount the challenge presented by this poor solubility, the gelling polysaccharide shows potential in ameliorating SPI. In this study, SPI/Flammulina velutipes polysaccharide (FVP) hydrogels were prepared under four mixing ratios (32:1, 20:1,15:1 and 10:1, w/w) at both pH6.5 and pH3.5, respectively. The stability of hydrogels and its immunostimulatory impact on RAW264.7 cells were assessed. Initial results revealed that water holding capacity increased when increasing the mixing ratios, likely to be the results of enhanced electrostatic interaction between SPI and FVP. The addition of FVP contributed to the improved swelling ratio and lowered the degradation ratio. Such structure feature was shown to be favorable for hydrogels to culture cells. More importantly, SPI/FVP hydrogels demonstrated no cytotoxic effect on cell metabolic activity. The culture of SPI/FVP hydrogels enhanced the immunostimulatory capacity in RAW264.7 cells by increasing phagocytosis and inducing the production of pro-inflammatory cytokines. The performances of the hydrogels made at pH3.5 were superior to those prepared at pH6.5. Our results suggested SPI/FVP hydrogels may provide application potential for the development of functional foods.

Molecular Properties of Flammulina velutipes Polysaccharide-Whey Protein Isolate (WPI) Complexes via Noncovalent Interactions.

Whey protein isolate (WPI) has a variety of nutritional benefits. The stability of WPI beverages has attracted a large amount of attention. In this study, Flammulina velutipes polysaccharides (FVPs) interacted with WPI to improve the stability via noncovalent interactions. Multiple light scattering studies showed that FVPs can improve the stability of WPI solutions, with results of radical scavenging activity assays demonstrating that the solutions of the complex had antioxidant activity. The addition of FVPs significantly altered the secondary structures of WPI, including its α-helix and random coil. The results of bio-layer interferometry (BLI) analysis indicated that FVPs interacted with the WPI, and the equilibrium dissociation constant (KD) was calculated as 1.736 × 10−4 M in this study. The in vitro digestibility studies showed that the FVPs protected WPI from pepsin digestion, increasing the satiety. Therefore, FVPs effectively interact with WPI through noncovalent interactions and improve the stability of WPI, with this method expected to be used in protein-enriched and functional beverages.

Green fabrication of seedbed-like Flammulina velutipes polysaccharides–derived scaffolds accelerating full-thickness skin wound healing accompanied by hair follicle regeneration

A novel seedbed-like scaffold was firstly fabricated by the “frozen sectioning” processing method using Flammulina velutipes as a raw material. The Flammulina velutipes polysaccharides scaffold is composed of a natural structure imitating the “ground” (connected and aligned hollow tubes with porous walls). Meanwhile, its biologically active components include polysaccharides and proteins, mimicking the “plant nutrition” in the seedbed. To further optimize the ground and nutrition components, Flammulina velutipes polysaccharides–derived scaffolds (FPDSs) were fabricated via the treatment of original Flammulina velutipes polysaccharides scaffold (labeled FPS) by NaOH, cysteine (labeled as FPS/NaOH, FPS/Cys, respectively). FPDSs were characterized by SEM, FTIR, XRD, water absorption and retention, and mechanical evaluations. From the results, FPS/NaOH and FPS/Cys lost the characteristic big tubes of original strips and had higher water absorption capacities comparing to FPS. Simultaneously, FPS/NaOH had better ductility, FPS/Cys had showed increased stiffness. Biological activities of FPDSs were tested against different types of bacteria exhibiting excellent anti-bacterial activity, and FPS/NaOH and FPS/Cys had dramatically higher anti-bacterial activity than FPS. The cytocompatibility of FPDSs was evaluated utilizing mouse fibroblast cell line (L929), and all FPDSs showed good cytocompatibility. The FPDSs were further applied to a rat full-thickness skin wound model, and they all exhibited obviously accelerated re-epithelialization, among which FPS/NaOH showed the greatest efficiency. FPS/NaOH could shorten the wound-healing process as evidenced by dynamic alterations of the expression levels of specific stagewise markers in the healing areas. Similarly, FPS/NaOH can efficiently induce hair follicle regeneration in the healing skin tissues. In summary, FPDSs exhibit potential functions as seedbeds to promote the regeneration of the “seed” including hair follicles and injured skin, opening a new avenue for wound healing.