Effects of drying on the structural characteristics and antioxidant activities of polysaccharides from Stropharia rugosoannulata

Nutritional and Therapeutic Potential of Stropharia rugosoannulata and Macrolepiota procera: From Composition to Health-Promoting Effect

Stropharia rugosoannulata and Macrolepiota procera have garnered considerable attention due to their distinctive flavor profile, culinary versatility, and potential nutritional and therapeutic benefits. They are a rich source of high-quality protein, dietary fiber, vitamins, and minerals, contributing to daily nutritional requirements and promoting overall well-being. Furthermore, they contain a diverse array of bioactive compounds, including polyphenols, flavonoids, and triterpenoids, which have demonstrated antioxidant, anti-inflammatory, and antitumor properties in previous studies. However, comprehensive reviews focusing on these two species remain limited. Therefore, this review summarizes the types of nutrients and bioactive compounds found in Stropharia rugosoannulata and Macrolepiota procera, along with their respective extraction methods. Moreover, the bioactivities of these compounds were discussed, aiming to provide a theoretical framework for the development of novel functional foods and nutraceuticals derived from Stropharia rugosoannulata and Macrolepiota procera.

Physicochemical and colon cancer HT-29 cell inhibitory property of homogeneous polysaccharide from Stropharia rugosoannulata

The development of active polysaccharides from edible mushrooms for antitumor drugs or functional foods has become a research hotspot. In this study, the physicochemical properties and monosaccharide composition of four homogeneous polysaccharides (CASP-0, CASP-1, CASP-2 and CASP-3) purified from alkali-extracted Stropharia rugosoannulata polysaccharides by DEAE-52 column were investigated, and the inhibitory effect against colon cancer HT-29 cell in vitro were explored. Results showed that four polysaccharides were homogeneous with molecular weights of 84.8 KDa (CASP-0), 11.1 KDa (CASP-1), 58.6 KDa (CASP-2) and 97.8 KDa (CASP-3). CASP-0 and CASP-3 contained glucose, mannose and galactose in molar ratios of 83.76:13.96:2.27 and 89.72:4.68:5.59, while CASP-1 and CASP-2 contained glucan. The four polysaccharides significantly reduced the cell viability of HT-29 cell in dose-dependent and time-dependent manner. With the increase of polysaccharide concentration, CASPs significantly inhibited the migration and invasion of HT-29 cell. The four polysaccharides induced HT-29 cell apoptosis by up-regulating the expression of Caspase-3 and Bax protein, and down-regulating the expression of Bcl-2 protein, suggesting that HT-29 cell apoptosis may be a mitochondria-mediated pathway. This study provides a theoretical basis for the potential application in medicine and functional food.

Characterization of gelatin-based composite films loaded with polysaccharide and carbon dots from Stropharia rugosoannulata and their application in pork fresh-keeping

In this study, bio-based composite films with enhanced barrier, mechanical, antioxidant and antimicrobial properties were prepared by incorporating Stropharia rugosoannulata waste (SP)-derived polysaccharides (SPP) and carbon dots (SPCDs) as an active substance into gelatin (GEL) matrix, which were evaluated for their potential application in pork preservation. The effects of varying concentrations of SPCDs on the morphology, microstructure, and overall performance of the films were systematically investigated. The findings demonstrated that the addition of SPCDs to the GEL/SPP matrix significantly improved the mechanical strength, water vapor permeability, and ultraviolet light blocking ability of the composite films. Specially, the GEL/SPP/SPCDs composite films containing 3 % carbon dots exhibited radical scavenging rates of 53.74 % for DPPH and 73.19 % for ABTS, along with inhibition rates of 58.37 % for E. coli and 70.25 % for S. aureus. Preservation experiments revealed that the prepared GEL/SPP/SPCDs-3 % films provided superior preservation effect on pork, highlighting their potential as eco-friendly active food packaging materials.

Structural, Functional, and Bioactive Properties of Sulfated Polysaccharides from Skipjack Tuna Skin as a Function of Drying Techniques

The study aims to investigate the impact of various drying techniques on the quality of sulfated polysaccharides (SP) extracted from Skipjack tuna (Katsuwonus pelamis) skin. Three drying methods, namely microwave drying (M-KPP), freeze-drying (F-KPP), and hot air drying (HA-KPP), are examined. The chemical and monosaccharide compositions of SP are significantly affected by the drying methods. The extraction yields for M-KPP, F-KPP, and HA-KPP are 3.30%, 3.11%, and 2.50%, respectively (P < 0.05). Additionally, HA-KPP, with 10.67% moisture content, exhibits the lowest moisture level among the dried samples (P < 0.05). Furthermore, the structural properties of SP remain consistent across different drying methods, as indicated by FTIR, XRD, and DSC analyses. F-KPP demonstrates the highest antioxidant properties. The functional and antimicrobial activities of SP are significantly influenced by the drying technique, with hot air drying resulting in increased foaming capacity and microwave drying showing enhanced antimicrobial activity. In conclusion, the findings demonstrate that the functionality and bioactivity of SP from tuna skin are greatly influenced by the drying technique employed, suggesting that the selection of the optimal method should be tailored to the desired properties of the SPs and given careful consideration.

Effects of Different Drying Methods on the Structural Characteristics and Multiple Bioactivities of Rosa roxburghii Tratt Fruit Polysaccharides

Drying conditions significantly impact the compositions and microstructures of polysaccharides, leading to various effects on their chemical characteristics and bioactivities. The objective of this study was to investigate how different industrial drying techniques, i.e., hot air drying, infrared drying, microwave vacuum drying, and freeze drying, affect the structural properties and biological activities of polysaccharides extracted from Rosa roxburghii Tratt fruit (RRTP). Results revealed that these drying methods significantly altered the extraction yield, molecular weights, monosaccharide ratios, contents of uronic acid and total sugars, gelling properties, particle sizes, thermal stability, and microstructures of RRTPs. However, the monosaccharide composition and functional groups of polysaccharides remained consistent across the different drying techniques. Biological activity assays demonstrated that RRTPs, particularly those processed through microwave vacuum drying (MVD-RRTP), exhibited excellent anti-linoleic acid oxidation, robust anti-glycosylation effects, and significant α-glucosidase inhibition in vitro. The outcomes of this research demonstrate that microwave vacuum drying serves as an effective pre-extraction drying method for RRTPs, enhancing their biological activities. This technique is particularly advantageous for preparing RRTPs intended for use in functional foods and pharmaceuticals, optimizing their health-promoting properties for industrial applications.

Fungi-derived natural antioxidants

In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.

Impact of high pressure pre-treatment and hot water extraction on chemical properties of crude polysaccharide extract obtained from mushroom (Volvariella volvacea)

An examination of the process of extracting crude polysaccharides from Volvariella volvacea solely through hot water treatment (HWE) at 60, 80, and 100 °C and through an approach involving high pressure processing (HPP) at 200, 400, and 600 MPa followed by HWE. The physiological properties of the polysaccharides could be explained by the structural analysis performed via FT-IR spectroscopy and NMR spectroscopy, which revealed the extract composition of the protein-bound polysaccharides connected by β-glycosidic bonds. Under the extraction conditions investigated in this current study, the recommended extraction condition was a combination of HPP (600 MPa, 10 min) and HWE (60 °C, 2 h). This condition gave high crude polysaccharide yields (with a 2-12% increase), and β-glucan content (with a 15-20% increase) without disrupting the β-glycosidic bond, as compared to using HWE alone. High pressure extraction could be an alternative technique for reduced extraction temperatures of active compounds from mushrooms.

Recent advances in the influences of drying technologies on physicochemical properties and biological activities of plant polysaccharides

Plant polysaccharides, as significant functional macromolecules with diverse biological properties, are currently receiving increasing attention. Drying technologies play a pivotal role in the research, development, and application of various foods and plant polysaccharides. The chemical composition, structure, and function of extracted polysaccharides are significantly influenced by different drying technologies (e.g., microwave, infrared, and radio frequency) and conditions (e.g., temperature). This study discusses and compares the principles, advantages, disadvantages, and effects of different drying processes on the chemical composition as well as structural and biological properties of plant polysaccharides. In most plant-based raw materials, molecular degradation, molecular aggregation phenomena along with intermolecular interactions occurring within cell wall components and cell contents during drying represent primary mechanisms leading to variations in chemical composition and structures of polysaccharides. These differences further impact their biological properties. The biological properties of polysaccharides are determined by a combination of multiple relevant factors rather than a single factor alone. This review not only provides insights into selecting appropriate drying processes to obtaining highly bioactive plant polysaccharides but also offers a fundamental theoretical basis for the structure-function relationship of these compounds.

Nutritional, Bioactive, and Flavor Components of Giant Stropharia (Stropharia rugoso-annulata): A Review

Giant Stropharia (S. rugoso-annulata) is an edible mushroom recommended for consumption by the Food and Agriculture Organization of the United Nations. It possesses significant culinary and medicinal functionalities. The characteristics of this mushroom include high protein content, abundant bioactive compounds, delicious and sweet taste, and pleasant aroma. In recent years, the S. rugoso-annulata industry has seen strong growth, especially in China. This article presents the first comprehensive and systematic review of the nutritional, bioactive, and flavor components of S. rugoso-annulata, as well as their influencing factors. This article provides scientific evidence for the production of high-quality S. rugoso-annulata mushrooms, the extraction of bioactive components, post-harvest storage, and culinary processing, aiming to promote the consumption of S. rugoso-annulata and the health of consumers.

The Nutrients and Volatile Compounds in Stropharia rugoso-annulata by Three Drying Treatments

This study aimed to examine the differences in the nutrients and volatile compounds of Stropharia rugoso-annulata after undergoing three different drying treatments. The fresh mushrooms were dried using hot air drying (HAD), vacuum freeze drying (VFD), and natural air drying (NAD), respectively. After that, the nutrients, volatile components, and sensory evaluation of the treated mushrooms were comparably analyzed. Nutrients analysis included proximate compositions, free amino acids, fatty acids, mineral elements, bioactive compositions, and antioxidant activity. Volatile components were identified by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and analyzed with principal component analysis (PCA). Finally, sensory evaluation was conducted by ten volunteers for five sensory properties. The results showed that the HAD group had the highest vitamin D₂ content (4.00 μg/g) and antioxidant activity. Compared with other treatments, the VFD group had higher overall nutrient contents, as well as being more preferred by consumers. Additionally, there were 79 volatile compounds identified by HS-SPME-GC-MS, while the NAD group showed the highest contents of volatile compounds (1931.75 μg/g) and volatile flavor compounds (1307.21 μg/g). PCA analysis suggested the volatile flavor compositions were different among the three groups. In summary, it is recommended that one uses VFD for obtaining higher overall nutritional values, while NAD treatment increased the production of volatile flavor components of the mushroom.

Three-phase extraction of polysaccharide from Stropharia rugosoannulata: Process optimization, structural characterization and bioactivities

The isolation of Stropharia rugosoannulata polysaccharide (SRP) by three-phase extraction was optimized, and its structure and biological activities were identified. The optimal extraction conditions were: mass fraction of ammonium sulfate, 20%; volume ratio of sample solution to t-butanol, 1:1.5; extraction temperature, 35°C. Under these conditions, the yield of SRP was 6.85% ± 0.13%. SRP was found to be composed of glucose (35.79%), galactose (26.80%), glucuronic acid (9.92%), fructose (8.65%), xylose (7.92%), fucose (4.19%), arabinose (3.46%) and rhamnose (3.26%), with the molecular weight of 27.52 kDa. The results of DPPH, hydroxyl, ABTS⁺ radical scavenging and reducing power tests showed that SRP had good antioxidant capacities. SRP had no cytotoxic effect on RAW264.7 macrophages at the concentrations of 25-200 μg/mL, and could significantly promote phagocytosis activity and cell migration according to CCK-8 assay, phagocytosis assay and cell scratch experiment. SRP can significantly stimulate the transcript expression levels of TNF-α, IL-1β and IL-6, as determined by RT-PCR and Western blot assays. SRP activated the TLR4/NF-κB signaling pathway, and autophagy also occurred. These results suggest that SRP is a safe antioxidant and immunomodulator, and that it can be used in the development of functional foods and/or pharmaceuticals.

Soil meso- and micro-fauna community in response to bamboo-fungus agroforestry management

Bamboo-fungus agroforestry management is an ecological model of sustainable production of moso bamboo forest, and Stropharia rugosoannulata has been widely planted in moso bamboo forest. However, little attention has been paid to soil fauna community in bamboo-fungus agroforestry system. Thus, the aim of this study was to investigate the response of soil fauna communities to agroforestry management, and to explore the relationships between soil fauna communities and soil properties. An experiment with 0, 1, 2 and 3 years of planting was carried out in an existing moso bamboo forest. The community composition of soil meso- and micro-fauna was investigated, and the soil properties were determined. Results showed that a total of 2968 individuals of soil meso- and micro-fauna, belonging to 8 classes and 13 groups were detected. The group number and density of soil fauna was highest right and then decreased. Planting Stropharia rugosoannulata in moso bamboo forest increased the density of dominant groups, but did not change its composition. Shannon-Weiner diversity index (H), Margalef richness index (D) and Density-Group diversity index (DG) were the highest one year after planting the fungus, while Simpson dominance index (C) was the lowest in the meantime. Contents of soil moisture (SMC), organic matter (SOM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) increased first and then decreased with the increase of planting years, peaking at 1 year after planting, while the pH value continued to increase. Responses of soil fauna community were associated with soil physicochemical properties. Redundancy analysis (RDA) showed that SOM was the main environmental factor driving the variation of soil fauna community, followed by TP and TN. In conclusion, planting Stropharia rugosoannulata in moso bamboo increased the diversity and abundance of soil fauna communities due to its contribution to abundance of organic matter and supply of nutrients.

Effect of various drying methods on the physicochemical characterizations, antioxidant activities and hypoglycemic activities of lychee (Litchi chinensis Sonn.) pulp polysaccharides

Suitable drying method is critical for the preservation of physicochemical and pharmacological quality of lychee pulp polysaccharides (LPPs). In current work, the effects of five drying methods, i.e. air drying (A), infrared drying (I), heat pump drying (H), vacuum freeze drying (F) and freeze vacuum drying combined with heat pump drying (FH) on the physicochemical characterizations, antioxidant activities and hypoglycemic activities of LPPs were explored. Results showed all five drying methods led to thermal aggregation of LPPs and the stronger the thermal effect induced by drying, the more serious the aggregations were. Additionally, the thermal aggregation significantly affected the composition, structure and biological activity of LPPs. Less thermal aggregation was observed in LPPF and LPPFH, which exhibited stronger oxygen, DPPH and ABTS radical scavenging activities, higher ferric-reducing power and better α-glycosidase and α-amylase inhibition activities, resulting from their higher contents of neutral sugar, protein and uronic acid and lower molecular weight than LPPA and LPPI. Besides, FH consumed about half drying time and one fifth energy of F. Therefore, from industrial perspective, FH is a promising alternative to F for producing LPPs by comprehensively considering physicochemical characterizations, bioactivity as well as energy consumption.

Whole Genome Sequence of an Edible Mushroom Stropharia rugosoannulata (Daqiugaigu)

Stropharia rugosoannulata, also known as Daqiugaigu in China, is a well-known edible mushroom that has been widely cultivated in China in recent years. Many studies have focused on its nutrients, bioactive compounds, and lignin degradation capacity, although there are few molecular and genetic breeding studies due to the lack of genomic information. Here, we present the 47.9 Mb genome sequence of an S. rugosoannulata monokaryotic strain (A15), which has 20 contigs and an N50 of 3.64 Mb, which was obtained by a combination of Illumina and Nanopore sequencing platforms. Further analysis predicted 12,752 protein-coding genes, including 486 CAZyme-encoding genes. Phylogenetic analysis revealed a close evolutionary relationship between S. rugosoannulata and Hypholoma sublateritium, Psilocybe cyanescens, and Galerina marginata based on single-copy orthologous genes. Proteomic analysis revealed different protein expression profiles between the cap and the stipe of the S. rugosoannulata fruiting body. The proteins of the stipe associated with carbon metabolism, energy production, and stress-response-related biological processes had higher abundance, whereas proteins involved in fatty acid synthesis and mRNA splicing showed higher expression in the cap than in the stipe. The genome of S. rugosoannulata will provide valuable genetic resources not only for comparative genomic analyses and evolutionary studies among Basidiomycetes but also for alleviating the bottlenecks that restrict the molecular breeding of this edible mushroom.