Rheological and microstructural properties of polysaccharide obtained from the gelatinous Tremella fuciformis fungus

Rheological property and thermodynamic parameters of Ficus carica Linn. pectin: A natural low-methoxyl pectin (LMP) with excellent pseudoplasticity

With the annual increase in the production of fig fruit (Ficus carica Linn.) in China, the processing and utilization of its by-products have become an important topic in fig research. In this study, a new type of natural low-methoxyl pectin (LMP) was obtained from figs by acid extraction (DE = 44.42 %). Fig pectin was an acidic heteropolysaccharide with a molecular weight of 75.9 kDa, and it was composed of galacturonic acid (248.09 mg/g), and neutral sugars including galactose (15.37 mg/g), arabinose (13.23 mg/g), rhamnose (6.74 mg/g), glucuronic acid (6.27 mg/g), xylose (0.78 mg/g), and fucose (0.26 mg/g). Shear-thinning behavior was shown at the concentration between 20 g/L - 60 g/L and the temperature between 5 °C - 50 °C of pectin solution, power law rheology model was used to describe the flow behavior of pectin solution. The apparent viscosity of pectin gradually raised with increasing concentration (at 25 °C, K is from 39.72 to 4140.39 Pa·sn, and n is from 0.85 to 0.42) and decreasing temperature (at 50 g/L, K is from 2233.55 to 17,549.48 Pa·sn, and n is from 0.37 to 0.47). Interestingly, pseudoplastic behavior was observed in all samples. Pectin solution exhibited thixotropic behavior, through the hysteresis loop through an up-down cycle in the shear rate-shear stress curve. The elastic modulus (G') and viscous modulus (G") of the pectin gradually reduced with decreasing concentration (20 g/L - 60 g/L) and increasing temperature (5°C - 50°C). Pectin exhibited a transition from elasticity (G' > G") to viscosity (G' < G") at higher concentration. The thermal degradation of pectin was mainly divided into three stages at different heating rate (5, 10, 15, 20 K-1). With the increasing of the heating rate, melt temperature (Tm) (240.66 °C - 250.69 °C) and enthalpy change (ΔH) (28.65 J/g - 90.43 J/g) increased. These results enriched understanding of the rheological property and thermodynamic parameters of fig pectin and were conducive to expanding the application of fig pectin in food processing.

Augmentation of exopolysaccharide synthesis and its influence on biofunctional properties of polysaccharide in Sanghuangporus vaninii via targeted overexpression of phosphoglucomutase

Phosphoglucomutase (PGM) is considered an essential catalyst in polysaccharide biosynthesis, plays a pivotal role in the early stage of carbon metabolism and the synthesis of nucleotide sugars. Polysaccharides are important active components of Sanghuangporus vaninii. Based on the transcriptomic data, the successful cloning and re-annotation of the putative 1353 - bp PGM took place, which encodes a protein of 49.45 kDa. In order to elucidate the function of this gene, overexpression and interference transformation systems were constructed in S. vaninii. The results revealed that the PGM is primarily responsible for regulating the interconversion between glucose-1-phosphate and glucose-6-phosphate. An up - regulation of PGM expression resulted in a significant increase in extracellular polysaccharide content, quantified at 7.72 % and 15.15 %, whereas a down - regulation of PGM expression resulted in a significant increase in intracellular polysaccharide content (33.68 % and 38.24 %). The antioxidant capacity of intracellular polysaccharide in strain, including hydroxyl radical scavenging, superoxide anion radical scavenging, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, ABTS+ radical scavenging and FRAP scavenging was significantly increased by RNA interference with the expression of PGM, while the overexpression of PGM was found to enhance the antioxidant capacity of extracellular polysaccharide to a certain degrees. Furthermore, the modulation of PGM expression had a significant impact on polysaccharide metabolic pathways, resulting in alterations in monosaccharide composition and impacting the content of cell wall components, and the microstructure of polysaccharides. These findings elucidate the polysaccharide biosynthetic pathway in S. vaninii, highlighting the PGM as a prime target for the propagation of high-yield polysaccharide-producing strains. This study stands as a basic reference for amplifying polysaccharide production via strategic metabolic regulation.

Rheological, functional, thermal and physicochemical properties of mucilage extracted from gelatinous pulp of Dillenia indica.L (elephant apple)

Dillenia indica L., commonly known as elephant apple and belongs to Dilleniaceae family, contains mucilagenous substances. This study investigates the rheological, functional, thermal, and physicochemical properties of mucilage derived from the gelatinous pulp of Dillenia indica as a novel hydrocolloid. The yield of freeze-dried mucilage powder obtained from gelatinous pulp was 4.20 %. The proximate composition analysis revealed contents of moisture (9.96 %), ash (7.84 %), protein (5.84 %), fat (0.08 %) and carbohydrate (36.64 %). Sugar composition analysis identified the presence of xylose (34.1 %), fucose (6 %), glucose (4.76 %), and cellobiose (3.45 %). FTIR spectra displayed characteristic peaks of polysaccharide in the extracted mucilage. The mucilage exhibited notable functional properties in terms of emulsion capacity (80.291 %) and stability (98.295 %), foaming capacity (17.863 %) and stability (61.79 %), water (16.005 g of water/g of sample) and oil holding capacity (1.543 g of oil/g of sample). Steady shear measurements at different concentrations (1, 2 and 3 % w/v) exhibited shear thinning behaviour. Frequency sweep experiments indicated the dominance of storage modulus(G') than loss modulus (G″) at mucilage concentrations (2 % and 3 %), suggesting weak gel formation capability. SEM and XRD pattern confirmed the amorphous nature of mucilage, while DSC and TGA analysis revealed high thermal stability up to 170 °C. These findings suggest that the remarkable properties of Dillenia indica mucilage make it a potential ingredient for food industry applications as a thickner, emulisifier, binder, and gelling agent.

Phased characterization of soy protein gel modified by lactobacillus plantarum JYLP-326 in cooperation with acidic tremella fuciformis fruiting body polysaccharide: Focus on structural network, interaction and gel properties

Soybean protein isolate (SPI) and acidic tremella fuciformis fruiting body polysaccharide (AP) were used to prepare phased products "sterilized soft gel (SPI-AP)" and "fermented strong gel (FSPI-AP)" to study the structural network, interaction and gel characteristics. The contents of α-helix (20.43 % to 25.36 %) and β-sheet (31.24 % to 35.12 %) of FSPI-AP increased compared with that of SPI. The introduction of AP and microorganisms improved the orderliness of peptide chain through non-covalent and covalent interactions, with hydrophobic (33.33 %), electrostatic (26.77 %), and disulfide bonds (24.45 %) being the dominant forces in the formation of gels. Furthermore, AP could decrease the crystallinity and disrupt the regular rigid structure of protein molecules, so FSPI-AP had stronger cohesion to resist external force. FSPI-AP had the highest proportion of interaction (12.57 %) in the interaction network, while SPI-AP was 9.07 %. This study will provide a new idea for innovating the application of protein-polysaccharide gel systems.

Instantaneous self-recovery and ultra-low detection limit hydrogel electronic sensor for temporomandibular disorders intelligent diagnosis

Temporomandibular disorders (TMD) intelligent diagnosis promises to elevate clinical efficiency and facilitate timely TMD management for patients. However, development of TMD intelligent diagnostic tools with high accuracy and sensitivity presents challenges, particularly in sensing minute deformations and ensuring rapid self-recovery. Here we report a biocompatible hydrogel electronic sensor with instantaneous self-recovery (within 2.1 s) and ultra-low detection limit (0.005% strain). It could efficiently diagnose disc displacement with reduction (DDwR) with satisfactory accuracy of 90.00%, and also had a clear indication of the typical clinical manifestations of DDwR and the timing of temporomandibular joint (TMJ) clicking, with a sensitivity of up to 100% in human compared to the diagnostic criteria for TMD (DC/TMD). Furthermore, a predictive model based on waveform features achieved 84.4% accuracy and 86% sensitivity, reducing dependence on physicians. In summary, the hydrogel sensor is expected to become a radiation-free, non-invasive, practical and effective tool for future TMD diagnosis.

A Novel Exopolysaccharide Produced by Sphingomonas sp. MT01 and Its Potential Application in Enhanced Oil Recovery

Sphingan is a crucial exopolysaccharide (EPS) produced by Sphingomonas genus bacteria with wide-ranging applications in fields such as food, medicine, and petroleum. In this study, a novel sphingan, named MT gum, was overproduced from the wild-type strain Sphingomonas sp. MT01 at a yield of 25.6 g/L in a 5 L fermenter for 52 h at 35 °C. The MT gum was mainly composed of D-glucose (65.91%) and L-guluronic acid (30.69%), as confirmed by RP-HPLC, with Mw 7.24 × 105 Da. The MT gum exhibited excellent rheology and pseudoplasticity characteristics while maintaining function in high-temperature and high-salinity environments. The viscosity retention rates of MT gum (0.1%, w/v) were 54.06% (80 °C, 50,000 mg/L salinity) and 34.78% (90 °C, 50,000 mg/L salinity), respectively. The apparent viscosity of MT solutions (0.1%, w/v) was much higher than that of welan solutions under the same conditions. The MT gum also had the property of instant dissolution and completely swelled in 40 min. Meanwhile, the MT gum was resistant to 3-10 mg/L Fe2+ in the reservoir conditions, ensuring its application in offshore oil fields. These findings suggested that the biopolymer MT gum produced by the strain MT01 had significant potential in enhanced oil recovery (EOR) of high-temperature and high-salinity oil reservoirs.

Glucono-δ-lactone induced Auricularia auricula polysaccharide-casein composite gels for curcumin loading and delivery

Polysaccharides could be used to form the network structure of casein (CA) gel, and affect its gelling properties. Auricularia auricula polysaccharide (AAP) has good gel properties and activity, however, how the AAP affects gelling properties of CA gels remains unclear. In this study, AAP and CA were acid-induced by glucono-δ-lactone (GDL) to prepare composite gels for curcumin loading. The effects of different AAP additions on the gel structure were emphasized. Water holding capacity, rheology, texture profile analysis, sulfhydryl content, surface hydrophobicity and gel microstructure showed that the composite gels were most structurally stable upon addition of 0.4 % AAP. The composite gels exhibited a higher strength and a more regular network structure compared to the CA gels. The results of turbidity studies showed that CA and AAP formed gels through electrostatic interactions due to pH < pI. The results of FT-IR, X-ray diffraction, fluorescence spectroscopy, and UV-Vis spectroscopy indicated that curcumin interacted with the CA and was successfully encapsulated within the gel. In addition, in vitro simulated digestion experiments demonstrated that the composite gels exhibited better protection against curcumin than the single CA gel. The results suggested that composite gels can be used as a curcumin carrier, which may enhance its wider application in the food and health industries.

Physicochemical and processing properties and in vitro fecal fermentation characteristics of Prunus cerasifera Ehrhart polysaccharide

Prunus cerasifera Ehrhart fruit polysaccharide (PCP) was obtained after determining the optimal extraction conditions for complex enzyme-assisted hot buffer extraction based on single-factor experiments and response surface methodology, followed by characterization of its physicochemical, processing, rheological, and biological properties. PCP was a thermally stable carbohydrate with acidic functional groups and a molecular weight of 1398.69 kDa, exhibiting smooth, dense flake and honeycomb network microstructures. PCP had favorable hygroscopicity, moisturizing properties, water and oil-holding capacity, proemulsification capability, and in vitro antioxidant activity. The apparent viscosity of PCP in an aqueous system was dependent on concentration and temperature and was altered by the variety and amount of metal ions added; its aqueous solutions exhibited strong viscosity and hydrogel-forming tendencies at suitable concentrations, along with excellent hydrogel properties after gelation. Furthermore, PCP favored the growth of beneficial gut microbiota and associated microbes responsible for producing essential short-chain fatty acids. Overall, PCP displayed high potential as a multifunctional additive for applications in the food, pharmaceutical, and cosmetic industries.

Low molecular weight polysaccharide of Tremella fuciformis exhibits stronger antioxidant and immunomodulatory activities than high molecular weight polysaccharide

Low molecular weight polysaccharides had higher bio-activity and bioavailability compared to ultra-high molecular weight polysaccharides, this study aimed to obtain low molecular weight polysaccharides from Tremella fuciformis (TFLP) by using high-temperature and high-pressure assisted hydrochloric acid method to degrade Tremella fuciformis polysaccharides (TFP), and the structural characteristics, in vivo antioxidant and immune enhancing activities of TFP and TFLP was explored through Caenorhabditis elegans (C. elegans) and mice model. It was found that TFP and TFLP were acidic polysaccharides with molecular weights of 2238 kDa and 3 kDa, respectively. The glycosidic bonding of TFP and TFLP was mainly composed of different configurations of mannopyranose. TFP and TFLP had excellent in vivo antioxidant activity and stress resistance by regulating the mRNA transcription level and metabolites in C. elegans. Results also showed that TFP and TFLP could enhance the antioxidant capacity and immunity of serum, spleen and small intestine tissues in normal mice and cyclophosphamide-induced immunosuppressive mice through regulating the relative transcription and expression levels of anti-inflammatory related signaling factors, and it has found that TFLP showed better immune enhancement and antioxidant activity than TFP. In addition, Akkermansia, Bacteroides and Alloprevotella were characteristic bacteria at the genus level in immunosuppressed mice intervened with TFLP, with a significant increase in relative abundance. The content of SCFAs significantly increased in immunosuppressed mice by TFLP. These results indicated that TFP and TFLP had potential in vivo antioxidant and immune enhancing activities.

Fabrication and characterization of oxidized starch-xanthan gum composite nanoparticles with efficient emulsifying properties

This study involved the preparation of nanoparticles by combining oxidized starch (OS) with xanthan gum (XG), and emulsions were prepared from this nanoparticle. The physical and chemical characteristics, as well as the emulsification properties of oxidized starch-xanthan gum composite nanoparticles (OGNP), were analyzed. The findings revealed that the OGNP retained spherical shape after the addition of XG, although their diameter increased from approximately 50-150 to 200-400 nm. Zeta potential decreased with XG content. Moreover, emulsions prepared from OGNP exhibited outstanding thermal stability, also showing enhanced storage stability. In addition, emulsions had different rheological properties at different pH values. The apparent viscosity and shear stress of emulsions under alkaline conditions were lower than that of neutral conditions. NaCl increased the apparent viscosity of OGNP-stabilized emulsions while reducing their thermal stability. The nanoparticles prepared in this study have efficient emulsification properties and can extend the application of OS.

Effect of tremella polysaccharides on the quality of collagen jelly: insight into the improvement of the gel properties and the antioxidant activity of yak skin gelatin

BACKGROUND

The present study aimed to investigate the effects of tremella polysaccharides on the gel properties and antioxidant activity of yak skin gelatin with a view to improving the quality of collagen jellies. The preparation of composite gels were performed by yak skin gelatin (66.7 mg mL-1) and tremella polysaccharides with different concentrations (0, 2, 4, 6, 8 mg mL-1), and finally the collagen jelly was prepared by composite gel (yak skin gelatin: 66.7 mg mL-1; tremella polysaccharides:6 mg mL-1) with the best performance.

RESULTS

Tremella polysaccharides not only improved the hardness, springiness, gel strength, water holding capacity and melting temperature of yak skin gelatin, but also enhanced the composite gel's scavenging activity against ABTS radicals, DPPH radicals, O2 and OH radicals. The filling of tremella polysaccharides into the gelatin network increased the number of crosslinking sites inside the gel, which resulted in the gel network structure becoming dense and orderly. The gel particles became finer and more uniform, and the thermal stability was improved. Furthermore, the sensory score of commercially available gelatin jelly decreased more rapidly during storage compared to the composite gel jelly.

CONCLUSION

The gel properties and antioxidant activity of yak skin gelatin were improved by adding tremella polysaccharides, and then the quality and storage properties of the jelly were improved, which also provided technical reference for the development of functional gel food. © 2024 Society of Chemical Industry.

Effect of sanxan as novel natural gel modifier on the physicochemical and structural properties of microbial transglutaminase-induced mung bean protein isolate gels

Mung bean protein isolate (MBPI) has attracted much attention as an emerging plant protein. However, its application was limited by the poor gelling characteristics. Thus, the effect of sanxan (SAN) on the gelling behavior of MBPI under microbial transglutaminase (MTG)-induced condition were explored in this study. The results demonstrated that SAN remarkably enhanced the storage modulus, water-holding capacity and mechanical strength. Furthermore, SAN changed the microstructure of MBPI gels to become more dense and ordered. The results of zeta potential indicated the electrostatic interactions existed between SAN and MBPI. The incorporation of SAN altered the secondary structure and molecular conformation of MBPI, and hydrophobic interactions and hydrogen bonding were necessary to maintain the network structure. Additionally, in vitro digestion simulation results exhibited that SAN remarkably improved the capability of MBPI gels to deliver bioactive substances. These findings provided a practical strategy to use natural SAN to improve legume protein gels.

Controlled dissolution of physically cross-linked locust bean gum - κ-carrageenan hydrogels

Most hydrogels swell but do not dissolve in water since their chains are tied to each other. Nevertheless, some hydrogels disintegrate under physiological conditions, a property that could be beneficial in emerging applications, including sacrificial materials, 3D bioprinting, and wound dressings. This paper proposes a novel approach to control the dissolution rate of hydrogels based on the integration of kappa carrageenan nanoparticles (KCAR-NPs) into kappa carrageenan (KCAR) and locust bean gum (LBG) hydrogels to obtain a three-component hybrid system. KCAR and LBG are known to have synergistic interactions, where physical interactions and chain entanglements lead to their gelation. We hypothesized that integrating the bulky nanoparticles would disturb the three-dimensional network formed by the polysaccharide chains and enable manipulating the dissolution rate. Compression, water absorption, rheology, and cryo-scanning electron microscopy measurements were performed to characterize the physical properties and structure of the hydrogels. The hybrid hydrogels displayed much faster dissolution rates than a control system without nanoparticles, which did not completely dissolve within 50 days and offered a cutting-edge means to finely adjust hydrogel dissolution through modulation of KCAR and KCAR-NPs concentrations. The new hydrogels also exhibited shear-thinning and self-healing properties resulting from the weak and reversible nature of the physical bonds.

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.

A review of the fungal polysaccharides as natural biopolymers: Current applications and future perspective

As a unique natural resource, fungi are a sustainable source of lipids, polysaccharides, vitamins, proteins, and other nutrients. As a result, they have beneficial medicinal and nutritional properties. Polysaccharides are among the most significant bioactive components found in fungi. Increasing research has revealed that fungal polysaccharides (FPS) contain a variety of bioactivities, including antitumor, antioxidant, immunomodulatory, anti-inflammatory, hepatoprotective, cardioprotective, and anti-aging properties. However, the exact knowledge about FPS and their applications related to their future possibilities must be thoroughly examined to enhance a better understanding of this sustainable biopolymer source. Therefore, FPS' biological applications and their role in the food and feed industry, agriculture, and cosmetics applications were all discussed in this work. In addition, this review highlighted the mode of action of FPS on human diseases by regulating gut microbiota and discussed the mechanism of FPS as antioxidants in the living cell. The structure-activity connections of FPS were also highlighted and explored. Moreover, future perspectives were listed to pave the way for future studies of FPS applications. Hence, this study can be a scientific foundation for future FPS research and industrial applications.

Development of soy protein isolate gels added with Tremella polysaccharides and psyllium husk powder as 3D printing inks for people with dysphagia

The aim of this study was to investigate the feasibility of soy protein isolate (SPI) gels added with Tremella polysaccharides (TPs) and psyllium husk powder (PHP) as 3D printing inks for developing dysphagia-friendly food and elucidate the potential mechanism of TPs and PHP in enhancing the printing and swallowing performance of SPI gels. The results indicated that the SPI gels with a TP : PHP ratio of 3 : 7 could be effectively used as printing inks to manufacture dysphagia-friendly food. The addition of TPs increased the free water content, resulting in a decrease in the viscosity of the SPI gels, which, in turn, reduced the line width of the 3D-printed product and structural strength of the gel system. The addition of PHP increased disulfide bond interactions and excluded volume interactions, which determined the mechanical strength of SPI gels and increased the line width of the printed product. The synergistic effects between TPs and PHP improved the printing precision and structural stability. This study presents meaningful insights for the utilization of 3D printing in the creation of dysphagia-friendly food using protein-polysaccharide complexes.

Preparation technologies, structural features, and biological activities of polysaccharides from Mesona chinensis Benth.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Mesona chinensis Benth. (or Platostoma palustre (Blume) A. J. Paton) is an important medicinal and edible plant also known as the Hsian-tsao in China and Southeast Asian countries. It is cold in nature and sweet in taste, with the effects of clearing heat, relieving heatstroke and diuretic, and traditionally used to treat heatstroke, erysipelas, hypertension, joint pain and other diseases in folk medicine. It is also a popular supplement with the function of detoxifying and heat-clearing use in Asia. It is used to be processed into the popular tea, Bean jelly, and so on. Published studies have demonstrated that polysaccharides from M. chinensis (MCPs) are one of the principal bioactive ingredients with a variety of health-promoting effects in the prevention and treatment of diseases, including antioxidant, immunomodulation, anti-inflammatory, hepatoprotective, anti-tumor, hypoglycemic, regulation of gut microbiota, and other pharmacological properties.

AIM OF THE REVIEW

This review aims to compile the extraction and purification methods, structural characteristics, pharmacological activities including the mechanism of action of MCPs, and to further understand the applications of M. chinensis in order to lay the foundation for the development of MCPs.

MATERIALS AND METHODS

By inputting the search term "Mesona chinensis polysaccharides", relevant research information was obtained from databases such as PubMed, Google Scholar, Web of Science, and China National Knowledge Infrastructure (CNKI).

RESULTS

More than 40 polysaccharides have been extracted from M. chinensis, different extraction and purification methods have been described, as well as the structural features and pharmacological activities of MCPs have been systematically reviewed. Polysaccharides, as important components of M. chinensis, were mainly extracted by methods such as hot water dipping method, hot alkali extraction method, enzyme-assisted extraction method and ultrasonic-assisted extraction method, subsequently obtained by decolorization, deproteinization, removal of other small molecules and separation on various chromatographic columns. The chemical composition and structure of MCPs show diversity and have a variety of pharmacological activities, including antioxidant, immunomodulation, anti-inflammatory, hepatoprotective, anti-tumor, hypoglycemic, regulation of gut microbiota, and so on.

CONCLUSIONS

This article systematically reviews the research progress of MCPs in terms of extraction and purification, structural characteristics, rheological gel properties, pharmacological properties, and safety assessment. The potentials and roles of M. chinensis in the field of medicine, functional food, and materials are further highlighted to provide references and bases for the high-value processing and utilization of MCPs.

Novel Post-Harvest Preservation Techniques for Edible Fungi: A Review

Edible fungi are well known for their rich nutrition and unique flavor. However, their post-harvest shelf-life is relatively short, and effective post-harvest preservation techniques are crucial for maintaining their quality. In recent years, many new technologies have been used for the preservation of edible fungi. These technologies include cold plasma treatment, electrostatic field treatment, active packaging, edible coatings, antimicrobial photodynamic therapy, and genetic editing, among others. This paper reviews the new methods for post-harvest preservation of mainstream edible fungi. By comprehensively evaluating the relative advantages and limitations of these new technologies, their potential and challenges in practical applications are inferred. The paper also proposes directions and suggestions for the future development of edible fungi preservation, aiming to provide reference and guidance for improving the quality of edible fungi products and extending their shelf-life.

The Emulsification and Stabilization Mechanism of an Oil-in-Water Emulsion Constructed from Tremella Polysaccharide and Citrus Pectin

The objective of this study was to investigate the feasibility of the mixture of tremella polysaccharide (TP) and citrus pectin (CP) as an emulsifier by evaluating its emulsifying ability/stability. The results showed that the TP:CP ratio of 5:5 (w/w) could effectively act as an emulsifier. CP, owing its lower molecular weight and highly methyl esterification, facilitated the emulsification of oil droplets, thereby promoting the dispersion of droplets. Meanwhile, the presence of TP enhanced the viscosity of emulsion system and increased the electrostatic interactions and steric hindrance, therefore hindering the migration of emulsion droplets, reducing emulsion droplets coalesce, and enhancing emulsion stability. The emulsification and stabilization performances were influenced by the molecular weight, esterified carboxyl groups content, and electric charge of TP and CP, and the potential mechanism involved their impact on the buoyant force of droplet size, viscosity, and steric hindrance of emulsion system. The emulsions stabilized by TP-CP exhibited robust environmental tolerance, but demonstrated sensitivity to Ca2+. Conclusively, the study demonstrated the potential application of the mixture of TP and CP as a natural polysaccharide emulsifier.

The Effects of Tremella fuciformis Polysaccharide on the Physicochemical, Multiscale Structure and Digestive Properties of Cyperus esculentus Starch

In this study, we have investigated the effects of Tremella fuciformis polysaccharide (TP) on the pasting, rheological, structural and in vitro digestive properties of Cyperus esculentus starch (CS). The results showed that the addition of TP significantly changed the pasting characteristics of CS, increased the pasting temperature and pasting viscosity, inhibited pasting, reduced the exudation of straight-chain starch and was positively correlated with the amount of TP added. The addition of the appropriate amount of TP could increase its apparent viscosity and enhance its viscoelasticity. The composite system of CS/TP exhibited higher short-range ordered structure and solid dense structure, which protected the crystal structure of CS, but was related to the amount of TP added. In addition, the introduction of TP not only decreased the in vitro digestion rate of CS and increased the content of slow-digestible starch (SDS) and resistant starch (RS), but also reduced the degree of digestion. Correlation studies established that TP could improve the viscoelasticity, relative crystallinity and short-range order of the CS/TP composite gel, maintain the integrity of the starch granule and crystalline structure, reduce the degree of starch pasting and strengthen the gel network structure of CS, which could help to lower the digestibility of CS.

The effect of sequential extraction on the physicochemical and rheological properties of Naematelia aurantialba polysaccharides

To overcome the difficulty of separation and low rate of extraction caused by highly viscous polysaccharides from Naematelia aurantialba (NA), four N. aurantialba polysaccharides (NAPs) were sequentially extracted using water (enzyme-/ultrasound-assisted extraction), alkali (0.1 mol/L NaOH), and acid (0.1 mol/L HCl), and named E-NAP, U-NAP, Al-NAP, and Ac-NAP. The properties of four NAPs were different. The yields of NAPs were 26.05 % (Ac-NAP) > 20.33 % (Al-NAP) > 17.99 % (U-NAP) > 12.77 % (E-NAP), respectively. The monosaccharide composition of NAPs was composed primarily of mannose, xylose, glucose, glucuronic acid, and galactose. Sequential extraction improved the purity and solubility of NAPs, but decreased the particle size, thermal stability, water retention, and crystallinity. Two polysaccharides, U-NAP and Al-NAP, had a triple helix structure. All the NAPs were pseudoplastic fluids with concentration/frequency-dependent entangled structure. Al-NAP with the highest viscosity exhibited an elastic gel, while Ac-NAP with the lowest viscosity was a viscous gel. The behavior of NAPs differed from that predicted using the Cox-Merz rule, and in particular, E-NAP and U-NAP more significantly deviated from the rule. In this study, four NAPs with different properties were extracted sequentially, which provided a theoretical basis for the down-stream processing with high added-value and utilization of NA and NAP.

Polysaccharide from Clitocybe squamulosa: Gel-forming properties and its compound effect with food thickener

To study the gel-forming properties of polysaccharide from the fruiting body of Clitocybe squamulosa (CSFP) and its degradation product (UH-CSFP), the changes in steady-state and dynamic rheological properties of CSFP and UH-CSFP under different conditions (polysaccharide mass fraction, temperature, pH, and salt ion concentration) were studied. Polysaccharides with good gel-forming properties were selected and mixed with common edible thickeners (gelatin, guar gum, and locust bean gum), after which the properties of the composite gel were assessed. The steady-state rheological results showed that CSFP and UH-CSFP were pseudoplastic fluids, their apparent viscosity decreased with increasing temperature, the viscosity was greatest when the pH was 7. The addition of Na+ and Ca2+ could increase the viscosity, and the viscosity of UH-CSFP was lower than that of CSFP at the same mass fraction. The results of dynamic rheology indicated that G´ and G´´ of CSFP and UH-CSFP increased with increasing mass fraction, pH, and ion concentration (0.01 M to 1 M), and G´´ was always smaller than G´ indicating weak gel behavior. The thixotropy-related experimental results showed that the thixotropy ring area of CSFP and UH-CSFP increased with increasing mass fraction, the ring area of CSFP was larger than that of UH-CSFP, and the gel strength of CSFP was greater than that of UH-CSFP. The results of CSFP and three types of edible gels showed that the composite gels were pseudoplastic fluids, and their apparent viscosity was ranked (in descending order) as follows: guar bean gum, locust bean gum, and gelatin. The addition of CSFP improved the gel-forming properties of guar gum but did not significantly improve the gel properties of locust bean gum and gelatin. This study provides a theoretical basis for the selection of processing methods and the application of polysaccharides.

Effect of polysaccharide concentration on heat-induced Tremella fuciformis polysaccharide-soy protein isolation gels: Gel properties and interactions

The formation of a single soybean protein isolate (SPI) gel is limited by the processing conditions, and has the disadvantages of poor gel property, and it is usually necessary to add other biomacromolecules to improve its property. In this study, we investigated the effects of polysaccharide concentration on gel properties and interaction mechanisms of Tremella fuciformis polysaccharide (TFP)-SPI complexes. It was found that (1) the rheological properties, texture properties, water-holding properties, and thermal stability of TFP-SPI composite gels were improved with the addition of TFP (0.25-2.0 %, w/v) in a concentration-dependent manner; (2) hydrogen bond, the electrostatic interaction, hydrophobic interaction, and disulfide bond in the gel system increased with the increase of TFP concentration; (3) the electrostatic and hydrophobic interactions played an important role in the formation of the TFP-SPI composite gel while hydrogen bond formation was the least contributor to the binary composite gel network. Overall, TFP is not only a critical health food but also a promising structural component for improving the gel properties of SPI.

Fabrication of resveratrol-loaded soy protein isolate-glycyrrhizin nanocomplex for improving bioavailability via pH-responsive hydrogel properties

Resveratrol (RES) is a functional polyphenol that suffers from low water solubility and poor bioavailability. A novel RES-loaded soy protein isolate-dipotassium glycyrrhizinate (SPI-DG) nanocomplex (RES@SPI-DG) was designed and evaluated in this study. RES@SPI-DG was prepared using a simple but novel self-assembly ultrasonic-assisted pH-driven method. The interactions between RES and SPI-DG were non-covalent bonds, including hydrophobic interactions, hydrogen bonds, and van der Waals interactions. RES@SPI-DG exhibited high encapsulation efficiency (97.60 ± 0.38 %) and loading capacity (8.74 ± 0.03 %) of RES with a uniform small size (68.39 ± 1.10 nm). RES in RES@SPI-DG was in an amorphous state and demonstrated a 24-h apparent solubility 482.53-fold higher than bare RES. RES@SPI-DG also showed strong in vitro antioxidant properties. The pH-responsive hydrogel character of SPI-DG makes it an effective intestine-targeted delivery system that could retard the release of RES in a simulated stomach and accelerate it in a simulated intestine. In animal experiments, the bioavailability of RES@SPI-DG was 5.17 times higher than that of bare RES, and the biodistribution was also significantly improved. RES@SPI-DG demonstrated a strong hepatoprotective effect against overdose acetaminophen-induced liver injury. The SPI-DG complex might be a promising nano-platform for enhancing the bioavailability and efficacy of hydrophobic polyphenols such as RES.

Effects of Lactobacillus plantarum FM 17 fermentation on jackfruit polysaccharides: Physicochemical, structural, and bioactive properties

Fermentation is a novel technology for modifying polysaccharides in fruits and improving their bioactivities. In this work, we introduced Lactobacillus plantarum FM 17 to ferment jackfruit pulp and subsequently purified polysaccharides from unfermented (JP) and fermented jackfruit pulp (JP-F). Furthermore, the physicochemical, structural, and bioactive properties of JP and JP-F were investigated. Results showed fermentation dropped the glucuronic acid, molecular weight, and particle size of JP-F by 15.62 %, 23.92 %, and 39.43 %, respectively, compared with those of JP. JP-F showed higher solubility than JP but lower apparent viscosity and thermal stability. Additionally, FT-IR spectra and X-ray diffraction analysis showed that fermentation did not alter the different types of glycosidic bonds and the fundamental polysaccharide structure. Moreover, JP-F exhibited stronger DPPH and ABTS free radical scavenging properties than JP and stronger stimulation on macrophage secretion of NO and IL-6 in RAW 264.7 cells. Therefore, using L. plantarum FM 17 for fermentation can alter physical and chemical properties of jackfruit pulp polysaccharides, enhancing their bioactivities.

Structural Characterization and Anti-Inflammatory Activity of Polysaccharides from Tremella fuciformis on Monosodium Urate-Stimulated RAW264.7 Macrophages

The structural characteristics and anti-inflammatory activity of Tremella fuciformis polysaccharides (TFPs) were investigated. The study showed that TFPs were mainly composed of mannose, rhamnose, glucuronic acid, glucose, galactose, xylose, and fucose. TFPs significantly inhibited monosodium urate (MSU)-induced inflammation of RAW264.7 cells, as well as the secretion levels of TNF-α, IL-1β, and IL-18 cytokines. The concentrations of malondialdehyde and reactive oxygen species in RAW264.7 macrophages were reduced, but superoxide dismutase activity was increased. RNA-Seq technology was applied to explore the mechanisms of TFPs ameliorating MSU-induced inflammation of RAW264.7 macrophages. Results revealed that TFPs significantly reduce MSU-stimulated inflammatory damage in RAW 264.7 cells by inhibiting signaling pathways like the hypoxia inducible factor-1 (HIF-1) signaling pathway and erythroblastic oncogene B (ErbB) signaling pathway. This study provides a foundation for TFPs to be developed as novel anti-inflammatory drugs.

Antitumor Activity of Carboxymethyl Pachymaran with Different Molecular Weights Based on Immunomodulatory and Gut Microbiota

Carboxymethyl pachymaran (CMP) was treated via high-temperature and cellulase hydrolysis to obtain HTCMP, HTEC-24, and HTEC-48. The chemical structure and in vivo antitumor activities of the four types of CMPs were investigated. Compared with CMP (787.9 kDa), the molecular weights of HTCMP, HTEC-24, and HTEC-48 were decreased to 429.8, 129.9, and 68.6 kDa, respectively. The viscosities and particle sizes of the CMPs could also decrease with the decline in the molecular weights. All the CMPs showed antitumor abilities, but HTEC-24 exhibited the best activity. In the animal study, when curing the spleen and thymus, CMPs displayed immunomodulatory effects by increasing the secretion of IFN-γ and IL2 in mice. The CMPs also exerted an antitumor ability by regulating the gut microbiota in tumor-bearing mice. Our results established a foundation to develop an antitumor drug with CMP.

Preparation of low molecular weight polysaccharides from Tremella fuciformis by ultrasonic-assisted H2O2-Vc method: Structural characteristics, in vivo antioxidant activity and stress resistance

Different methods were used to degrade Tremella fuciformis polysaccharides (TFP) and prepare low molecular weight polysaccharides of Tremella fuciformis (TFLP) to improve their bioavailability. It was found that the TFLP prepared by ultrasonic-assisted H2O2-Vc method showed the highest level of antioxidant activity and stress resistance in C. elegans. The structural characteristics, in vivo antioxidant and stress resistance of TFLP-1 were evaluated after isolation and purification of TFLP, it was found that TFLP-1 was an acid polysaccharide with a molecular weight of 75770 Da, which mainly composed of mannose. Meanwhile, it could regulate the antioxidant activity and stress resistance in C. elegans by upregulating the transcription of fat-5, fat-7, acs-2, glp-1, hsf-1, hsp-1, mtl-1, nhr-49, skn-1 and sod-3 mRNA. The improvement effects were closely related to the significant regulation of galactose metabolism, alpha linolenic acid metabolism, and pantothenate and CoA biosynthesis metabolic pathways. These results provided insights into the high value application of Tremella fuciformis in the food industry and the development of antioxidant related functional foods.