A Review on the Potential Reuse of Functional Polysaccharides Extracted from the By-Products of Mushroom Processing

Steam Explosion-Assisted Extraction of Ergosterol and Polysaccharides from Flammulina velutipes (Golden Needle Mushroom) Root Waste

In this work, steam explosion (SE) was applied to prompt the rapid extraction of ergosterol and polysaccharides from Flammulina velutipes root (FVR) waste. Ultrasound-assisted saponification extraction (UASE) followed by water extraction was used to prepare ergosterol and polysaccharides. The results indicated that SE destroyed the complicated structure of FVR and increased its internal porosity and surface roughness. SE caused the thermal degradation of FVR's structural components and increased the polysaccharide content 0.97-fold. As a result, the extraction yield and efficiency of ergosterol and polysaccharides were improved. The theoretical maximum extraction concentration (C∞) and diffusion coefficient (D) were increased by 34.10% and 78.04% (ergosterol) and 27.69% and 48.67% (polysaccharides), respectively. The extraction yields obtained within 20-30 min of extraction time exceeded those of untreated samples extracted after several hours. For polysaccharides, SE led to a significant reduction in the average molecular weight, increased the percentage of uronic acids and decreased the neutral sugar percentage. The monosaccharide composition was changed by SE, with an increase in the molar ratio of glucose of 64.06% and some reductions in those of other monosaccharides. This work provides an effective method for the processing of fungi waste and adds to its economic value, supporting its high-value utilization in healthcare products.

An Overview on Mushroom Polysaccharides: Health-promoting Properties, Prebiotic and Gut Microbiota Modulation Effects and Structure-function Correlation

Mushroom polysaccharides are recognized as "biological response modifiers". Besides several bioactivities, a growing interest in their prebiotic potential has been raised due to the gut microbiota modulation potential. This review comprehensively summarizes mushroom polysaccharides' biological properties, structure-function relationship, and underlying mechanisms. It provides a recent overview of the key findings in the field (2018-2024). Key findings and limitations on structure-function correlation are discussed. Although most studies focus on β-glucans or extracts, α-glucans and chitin have gained interest. Prebiotic capacity has been associated with α-glucans and chitin, while antimicrobial and wound healing potential is attributed to chitin. However, further research is of utmost importance. Human fecal fermentation is the most reported approach to assess prebiotic potential, indicating impacts on intestinal biological, mechanical, chemical and immunological barriers. Gut microbiota dysbiosis has been directly connected with intestinal, cardiovascular, metabolic, and neurological diseases. Concerning gut microbiota modulation, animal experiments have suggested proinflammatory cytokines reduction and redox balance re-establishment. Most literature focused on the anticancer and immunomodulatory potential. However, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemic, antilipidemic, antioxidant, and neuroprotective properties are discussed. A significant overview of the gaps and research directions in synergistic effects, underlying mechanisms, structure-function correlation, clinical trials and scientific data is also given.

Impacts of preparation technologies on biological activities of edible mushroom polysaccharides - novel insights for personalized nutrition achievement

Edible mushroom polysaccharides (EMPs) as a natural macromolecular carbohydrate have a very complex structure and composition. EMPs are considered ideal candidates for developing healthy products and functional foods and have received significant research attention due to their unique physiological activities such as immunomodulatory, anti-inflammatory, anti-tumor/cancer, gut microbiota regulation, metabolism improvement, and nervous system protection. The structure and monosaccharide composition of edible mushroom polysaccharides have an unknown relationship with their functional activity, which has not been widely studied. Therefore, we summarized the preparation techniques of EMPs and discussed the association between functional activity, preparation methods, structure and composition of EMPs, laying a theoretical foundation for the personalized nutritional achievements of EMP. We also establish the foundation for the further investigation and application of EMPs as novel functional foods and healthy products.

Sustainable Utilization of Mushroom By-Products Processed with a Combined Osmotic Dehydration Pretreatment and a Hot-Air-Drying Step

Mushroom production and consumption are gaining increased interest due to their unique flavor and nutritional value. However, in the mushroom industry, large amounts of by-products are generated, which have a high negative environmental and economic impact. In this study, an osmotic dehydration process followed by hot-air-drying was applied to mushroom stems to produce dried mushrooms as the end product. The osmotic dehydration conditions (concentration of hypertonic solution, specifically, 10-30% maltodextrin and 20-40% oligofructose; a treatment time of 40-80 min; and a temperature range of 30-50 °C) were optimized using response surface methodology (RSM). The results showed that a four-factor three-level Box-Behnken experimental design was effectively implemented to evaluate the effect of the process parameters and identify the optimal osmotic dehydration conditions for producing osmotically dehydrated mushrooms. The main factor affecting mass transfer was the osmosis temperature, and the optimal conditions were found to be 38 °C, 40% oligofructose and 19.3% maltodextrin as the osmotic agents, and 80 min of immersion time. Moreover, the results showed that osmotic pretreatment, in the optimal conditions, significantly reduced the required drying time of the by-products compared to traditional hot-air-drying, especially at milder drying temperatures. Consequently, the required energy was also reduced by at least 40% at 50 °C.

Active pullulan-based coatings incorporated with Auricularia auricular extracts for preserving potato fresh-cuts

In the present study, Auricularia auricular polysaccharides (AAP) and Auricularia auricular proteins (AAPR) obtained from the waste products of Auricularia auricular were incorporated into pullulan (PUL) to obtain active packaging films/coatings. Results showed that incorporating AAP/AAPR into PUL-based films decreased their transparency, but increased the compactness, thermal stability, antioxidant, and antimicrobial properties. Adding 2% PUL films with 10%:10% of AAP/AAPR exhibiting good mechanical properties were applied to fresh-cut potatoes to avoid spoilage during eight days of storage, with significantly decreased in browning index, weight loss, microbial growth prevention and the total soluble solids was maintained. These results substantiated that pullulan containing AAP/AAPR as an active film/coating with antioxidant and antimicrobial properties has significant potential for maintaining safety and quality of fresh-cut potatoes and extending their shelf life.

Optimization of Plasma Activated Water Extraction of Pleurotus ostreatus Polysaccharides on Its Physiochemical and Biological Activity Using Response Surface Methodology

This study focused on optimizing the extraction of P. ostreatus polysaccharides (POPs) using plasma-activated water (PAW). A single factor and response surface methodology were employed to optimize and evaluate the polysaccharide yield, physiochemical characteristics, and biological activities of POPs. The observed findings were compared to those obtained by the conventional hot water extraction method (100 °C, 3 h), as the control treatment. The optimal extraction conditions were obtained at 700 W PAW power, 58 s treatment time, 1:19 sample-to-water ratio, and 15 L/min gas flow rate. In these conditions, the PAW-treated samples experienced changes in surface morphology due to plasma etching, leading to a 288% increase in the polysaccharide yield (11.67%) compared to the control sample (3.01%). Furthermore, the PAW-treated sample exhibited superior performance in terms of biological activities, namely phenolic compounds (53.79 mg GAE/100 g), DPPH scavenging activity (72.77%), and OH scavenging activity (65.03%), which were 29%, 18%, and 38% higher than those of control sample, respectively. The results highlighted the importance of process optimization and provided new evidence for PAW as an alternative approach to enhance the extraction efficiency of POPs, a novel source of natural antioxidants which enables diverse applications in the food industry.

Quality Evaluation of Shiitake Blanched and Centrifuged Broths as Functional Instant Drinks

In the process of making mushrooms into vacuum-fried crisps, the resulting blanched broth (BB) and centrifuged broth (CB) are often discarded, thereby increasing the amount of wastewater and treatment costs. This study measured the proximate compositions, bioactive components, taste components, and minerals of freeze-dried BB and CB and then used functional indigestible dextrin (Fibersol-2) as a carrier to make these two broths into instant drinks. The solids of the BB and CB contained protein (16.88-19.21%), fat (0.01-0.23%), ash (12.89-13.50%), carbohydrate (67.28-70.00%), sugars and polyols (40.55-45.68%), free amino acids (6.58-6.69%), 5'-nucleotides (0.98-1.47%), and bioactive components, especially polysaccharides (4.53-7.45%), ergothioneine (both 0.19%), and total phenols (0.15-0.36%). The equivalent umami concentration of BB was 2.77-fold higher than that of the CB. Both BB and CB showed compositions and essential minerals that are rich in taste. Using a nine-point hedonic test, it was found that the solid contents of BB and CB in the instant drink affected the consumer's preference. The flavor and overall preference of instant drinks with 2.5% BB or CB were the best amongst consumers. Overall, the BB and CB were rich in nutrients and bioactive and taste components and could be developed as a functional food in the form of a drink.

Comparative Study of Different Protein Extraction Technologies Applied on Mushrooms By-products

Mushroom production is a growing sector as the demand for this product is increasing. The quantity of waste and by-products generated along the supply chain is however considerable (about 20% of the fresh weight is disposed). Although the recovery of chitosan from mushrooms has been extensively studied, little has been done to optimize the recovery of proteins, which make up to 20% of dry weight. In the present work, six different by-products were studied for their crude composition and their protein fraction was characterized in detail. Then, a comparative study was conducted on three different extraction techniques (environmentally friendly aqueous extraction, ultrasound-assisted extraction, and enzyme-assisted extraction). Enzyme-assisted extraction has proven to be the most efficient technique in terms of protein extraction yield, even though the protein fraction is extracted in the form of peptides and not whole proteins. The lowest degree of hydrolysis is instead given by the ultrasound-assisted extraction, which however shows a rather high degree of racemization which decreases the quality of the proteins. The aqueous extraction, despite the low extraction yield, gave the purest protein extracts.

Extraction and utilization of active substances from edible fungi substrate and residue: A review

The expansion of the edible fungi industry has resulted in the production of large amounts of edible fungus residues, causing great pressure on environmental protection.Therefore, research on edible fungus residue utilization has become a controversial issue. Thus far, numerous efforts have been devoted to separate active substances from edible fungus substrates and residues for high application value utilization. Building upon this, the main methods for extracting active substances from edible mushroom residues are reviewed, and the mechanisms, influencing factors, and trade-offs of the various methods are analysed. Furthermore, the existing and possible directions of utilization of the extracted active substances are reviewed and discussed. Finally, challenges and prospects for the extraction and utilization of different substances in edible fungus residues are proposed. This review provides an effective strategy for protecting the ecological environment and promoting the sustainable development of human society.

Chemical Characterization and Biological Functions of Hot Alkali-Soluble Crude Polysaccharide from the Water-Insoluble Residue of Macrocybe lobayensis (Agaricomycetes) Fruit Bodies

Macrocybe lobayensis owe popularity in several traditional cultures not only for delectable taste but also for its nutraceutical profile conveying great health benefits. Previous investigations have enumerated several bioactivities of the valuable mushroom such as antioxidant, anti-ageing, immune-modulation, and anti-tumor properties where polysaccharides played the key role. Macrofungi polymers are generally isolated by the conventional hot water process discarding the residue which still contains plenty of therapeutic components. The present study thus aimed to re-use such leftover of the edible macrofungus by immersing it in NaOH solution at high temperature supporting circular economy. Consequently a polysaccharide fraction, namely ML-HAP, was isolated that was found to be consisted of a homogenous heteropolysaccharide with molecular weight of ~ 128 kDa and β-glucan as the chief ingredient as evident by spectroscopy, gel-permeation chromatography, high performance thin-layer chromatography, and Fourier transform infrared. Antioxidant activity assays revealed that the macromolecules possess good radical scavenging, metal ion binding and reducing power. Nevertheless, strong immune-potentiation was also recorded as the extract triggered murine macrophage cell viability, pinocytosis, nitric oxide production and morpho-dynamics within 24 h where the best effect was executed at the level of 100 µg/mL. Altogether, the polysaccharides extracted from M. lobayensis exhibited a potent application prospect in functional food, pharmaceutical, nutraceutical and health care industries that could raise economic value of the underexplored mushroom.

Valorization of mushroom by-products: a review

With the rapid growth of the global economy and the global population, the production of solid waste has increased remarkably. Mushrooms are gaining popularity among researchers for their ability to turn waste into nutrients. However, a large number of by-products are produced during the industrial processing of mushrooms. Traditional waste management, focusing on the utilization and disposal of mushroom by-products, has attracted the attention of researchers. Meanwhile, the circular economy has become a multidisciplinary research field, and the valorization of mushroom by-products is a very important part of circular economy research. Various mushroom by-products of mushroom are reviewed in this paper. By-products are used in food as raw materials or functional components, in livestock and poultry feed after grinding/fermentation, and as electrochemical materials and papermaking materials. The by-products can also be used to produce ethanol and other biological sources of energy, as absorbing substances in sewage treatment, and as fertilizer in soil amendment. Mushroom processing by-products can be applied in various fields. To improve production efficiency, new extraction technology (including supercritical fluid technology and microwave extraction technology) can be adopted to increase the bioactive substance content in the by-products. Choosing appropriate processing temperature, time, and other processing conditions can also enhance product quality. Finally, more research is needed on the cost-effective utilization of the by-products and the feasibility of industrialization. © 2022 Society of Chemical Industry.

Edible Mushrooms for Sustainable and Healthy Human Food: Nutritional and Medicinal Attributes

Global food production faces many challenges, including climate change, a water crisis, land degradation, and desertification. These challenges require research into non-traditional sources of human foods. Edible mushrooms are considered an important next-generation healthy food source. Edible mushrooms are rich in proteins, dietary fiber, vitamins, minerals, and other bioactive components (alkaloids, lactones, polysaccharides, polyphenolic compounds, sesquiterpenes, sterols, and terpenoids). Several bioactive ingredients can be extracted from edible mushrooms and incorporated into health-promoting supplements. It has been suggested that several human diseases can be treated with extracts from edible mushrooms, as these extracts have biological effects including anticancer, antidiabetic, antiviral, antioxidant, hepatoprotective, immune-potentiating, and hypo-cholesterolemic influences. The current study focuses on sustainable approaches for handling edible mushrooms and their secondary metabolites, including biofortification. Comparisons between edible and poisonous mushrooms, as well as the common species of edible mushrooms and their different bioactive ingredients, are crucial. Nutritional values and the health benefits of edible mushrooms, as well as different biomedical applications, have been also emphasized. Further research is needed to explore the economic sustainability of different medicinal mushroom bioactive compound extracts and their potential applications against emerging diseases such as COVID-19. New approaches such as nano-biofortification are also needed to supply edible mushrooms with essential nutrients and/or to increase their bioactive ingredients.

Utilization of Aerobic Compression Composting Technology on Raw Mushroom Waste for Bioenergy Pellets Production

Raw mushroom waste has been an enormous solid waste, not only causing a huge cut on profit margin of mushroom industries but also leading to environmental pollution. Unfortunately, the current utilization methods, such as pharmaceutical extractions, are unable to keep up with the waste generation rate due to the large-scale mushroom production. Yet, the utilization of raw mushroom waste to produce biomass pellets for energetic purposes and the role of an electric composter on shortening the processing time remain unexplored. This is important because conventional composting, which takes a relatively long period (e.g., weeks to months), is less practical when it comes to commercial use of the biomass pellets. To explore this issue, an industrial composter with initial compost was utilized to process the raw mushroom waste, followed by pelletization. Extraction of the material inside the composter at different timing was carried out to determine the optimal processing time for optimal texture to form pellets. It was found that prolonged composting hour affected the pelletization process since moisture, which acts as a natural binder, reduced when the composting hour increased. The gross calorific value increased from 14.07 MJ/kg to 18.76 MJ/kg for raw mushroom waste and compost pellets at the fifth hour, respectively. This study revealed that the raw mushroom waste compost could serve as a valuable renewable energy source and that the production of energy-rich biomass compost fuel pellets without using any binder within a short composting duration is achievable with the aid of an in-vessel composter.

A synbiotic containing prebiotic prepared from a by-product of king oyster mushroom, Pleurotus eryngii and probiotic, Lactobacillus plantarum incorporated in diet to improve the growth performance and health status of white shrimp, Litopenaeus vannamei

This study aimed to evaluate the effects of a synbiotic composite an extract from a by-product of king oyster mushroom, Pleurotus eryngii (KOME), and probiotic Lactobacillus plantarum 7-40 on the growth performance and health status of white shrimp, Litopenaeus vannamei. The KOME was able to stimulate the growth of probiotic, but not the growth of Vibrio pathogens, including V. alginolyticus, V. parahaemolyticus, and V. harveyi. Four diets were formulated, including a control diet supplemented without prebiotic and probiotic, a basal diet supplemented with KOME (5 g kg^-1) (ME), a basal diet supplemented with probiotic (1 × 10⁸ CFU kg^-1) (LP), and a basal diet supplemented with KOME (5 g kg^-1) and probiotic (1 × 10⁸ CFU kg^-1) (SYN). Shrimp fed the ME, LP, and SYN diets had significantly higher survival than that of shrimp fed with the control diet for 8 weeks. Shrimp in the SYN group also had a significantly higher weight gain and total final weight in comparison with the control and other treatments. In the intestinal tract, lactic acid bacteria count was significantly higher in the SYN group, whereas the Vibrio-like bacteria count was significantly higher in the ME group than in the control group. For the health status assessment, the disease resistance of shrimp against V. alginolyticus was improved in all treatments compared to the shrimp in control. Shrimps in the SYN group had significantly lower cumulative mortality due to the significant increase in immune responses, including phenoloxidase, respiratory burst, and lysozyme activity, and the gene expression of pexn and pen4 in the haemocytes, and lgbp, sp, propoii, pexn, pen3a, pen4, and gpx in the haepatopancreas of shrimp as compared to the control. Therefore, it is suggested that a combination of KOME and probiotics can be used as a synbiotic to improve the growth performance and reduce the risk of infectious diseases caused by Vibrio and at the same time significantly contribute to the circular economy.

Preliminary Characterisation of Wastes Generated from the Rapeseed and Sunflower Protein Isolation Process and Their Valorisation in Delaying Oil Oxidation

Since rapeseed and sunflower meals are two of the most representative oilseed crops in the world, this study was focused on ethanol-wash solutes (EWS) obtained as wastes from the protein isolation process of rapeseed and sunflower meals. These meals have been previously valorised; however, the use of the EWS is unexplored. The present study is aimed at the characterisation of their phenolic profile, and antioxidant capacity for preventing lipid oxidation in rapeseed, sunflower, and soybean oil, which has been used as a reference oil. The sunflower EWS exhibited more total phenolic compounds (TPC) and antioxidant activity (119.39 ± 1.13 mg GA/g and 193.97 ± 9.77 mg TE/g, respectively) than the rapeseed one (103.44 ± 5.94 mg GA/g and 89.51 ± 3.17 mg TE/g). The phenolic identification showed hydroxybenzoic and protocatechuic acid in the rapeseed EWS, and pyrogallol and caffeic acid in the sunflower EWS, as the main representative phenols. Both EWS at 15% increased significantly (p < 0.05) the oxidative stability of the oils in the Rancimat equipment with values of antioxidant activity index (AAI) from 1.01 to 1.20, depending on the type of oil employed. In conclusion, the rapeseed and sunflower EWS showed great potential, and they could be used as a source of natural antioxidants within the food industry, replacing the synthetic ones, and promoting the circular economy since they are agro-food wastes.

Hot alkali-extracted antioxidative crude polysaccharide from a novel mushroom enhances immune response via TLR-mediated NF-κB activation: A strategy for full utilization of a neglected tribal food

Mushroom polysaccharides have been revered for decades as incredibly versatile compounds suitable for application in biomedical, pharmaceutical, food, and cosmetic industries. In that essence Russula alatoreticula, a traditionally appraised unique macrofungus, has earlier been explored to contain functional macromolecules elicited by hydrothermal and cold alkali systems. Remnants of that multistep extraction could further be utilized not only to isolate high-value components, but also to reduce waste material. With this in mind, we decided to recycle leftover residue of the tribal delicacy, rather than undervalue, by following heated NaOH reflux. Intriguingly, the effort resulted productive isolation of carbohydrate fraction (RualaHap) enriched in β-glucan that showed excellent antioxidant activity in terms of radical scavenging, chelating ability, and reducing power with EC₅₀ of 207-5000 μg/ml. Besides strong immune boosting prowess was also witnessed as exposure of RAW 264.7 cells to the metabolites influenced macrophage viability and phagocytosis in a time-dependent manner. Induction of intracellular NO and ROS generation was also enumerated along with aggrandized production of pseudopods representing hallmark of monocyte stimulation. Moreover, the treatment drastically triggered level of TLR-2, TLR-4, NF-κB, Iκ-Bα, iNOS, COX-2, TNF-α, IFN-γ, and IL-10 maintaining balance between M1 and M2 cytokines via TLR coordinated NF-κB pathway. Conclusively the research offers a roadmap for better utilization of a species boasted in traditional practice aiding future implementation of RualaHap as ingredients of nutraceuticals or functional foods. PRACTICAL APPLICATIONS: At present, macrofungal polysaccharides are regarded as an ideal resource for a range of safe uses encompassing direct contact or ingestion by human. In this context, RualaHap isolated from the wild edible mushroom, R. alatoreticula, could have a broad application prospect, particularly in development of natural therapeutics to ameliorate radical-induced ailment and immune-deficiency condition. The biopolymers could thus be utilized in functional diet or complementary medicine to improve health that in turn might raise local cost of the abandoned taxon boosting rural empowerment.

Classification of multicategory edible fungi based on the infrared spectra of caps and stalks

As a characteristic edible fungus with a high nutritional value and medicinal effect, the Bachu mushroom has a broad market. To distinguish among Bachu mushrooms with high value and other fungi effectively and accurately, as well as to explore a universal identification method, this study proposed a method to identify Bachu mushrooms by Fourier Transform Infrared Spectroscopy (FT-IR) combined with machine learning. In this experiment, two kinds of common edible mushrooms, Lentinus edodes and club fungi, were selected and classified with Bachu mushrooms. Due to the different distribution of nutrients in the caps and stalks, the caps and stalks were studied in this experiment. By comparing the average normalized infrared spectra of the caps and stalks of the three types of fungi, we found differences in their infrared spectra, indicating that the latter can be used to classify and identify the three types of fungi. We also used machine learning to process the spectral data. The overall steps of data processing are as follows: use partial least squares (PLS) to extract spectral features, select the appropriate characteristic number, use different classification algorithms for classification, and finally determine the best algorithm according to the classification results. Among them, the basis of selecting the characteristic number was the cumulative variance interpretation rate. To improve the reliability of the experimental results, this study also used the classification results to verify the feasibility. The classification algorithms used in this study were the support vector machine (SVM), backpropagation neural network (BPNN) and k-nearest neighbors (KNN) algorithm. The results showed that the three algorithms achieved good results in the multivariate classification of the caps and stalks data. Moreover, the cumulative variance explanation rate could be used to select the characteristic number. Finally, by comparing the classification results of the three algorithms, the classification effect of KNN was found to be the best. Additionally, the classification results were as follows: according to the caps data classification, the accuracy was 99.06%; according to the stalks data classification, the accuracy was 99.82%. This study showed that infrared spectroscopy combined with a machine learning algorithm has the potential to be applied to identify Bachu mushrooms and the cumulative variance explanation rate can be used to select the characteristic number. This method can also be used to identify other types of edible fungi and has a broad application prospect.