Production of a β-d-glucan-rich extract from Shiitake mushrooms (Lentinula edodes) by an extraction/microfiltration/reverse osmosis (nanofiltration) process

Pressurized Liquid (PLE) Truffle Extracts Have Inhibitory Activity on Key Enzymes Related to Type 2 Diabetes (α-Glucosidase and α-Amylase)

An optimized PLE method was applied to several truffle species using three different solvent mixtures to obtain bioactive enriched fractions. The pressurized water extracts contained mainly (1 → 3),(1 → 6)-β-D-glucans, chitins, and heteropolymers with galactose and mannose in their structures. The ethanol extracts included fatty acids and fungal sterols and others such as brassicasterol and stigmasterol, depending on the species. They also showed a different fatty acid lipid profile depending on the solvent utilized and species considered. Ethanol:water extracts showed interesting lipids and many phenolic compounds; however, no synergic extraction of compounds was noticed. Some of the truffle extracts were able to inhibit enzymes related to type 2 diabetes; pressurized water extracts mainly inhibited the α-amylase enzyme, while ethanolic extracts were more able to inhibit α-glucosidase. Tuber brumale var. moschatum and T. aestivum var. uncinatum extracts showed an IC₅₀ of 29.22 mg/mL towards α-amylase and 7.93 mg/mL towards α-glucosidase. Thus, use of the PLE method allows o bioactive enriched fractions to be obtained from truffles with antidiabetic properties.

Mushroom β-glucans: application and innovation for food industry and immunotherapy

Among the most important sources of β-glucans are edible and medicinal mushrooms. These molecules are components of the cellular wall of basidiomycete fungi (mushrooms) and can be extracted even from the basidiocarp as the mycelium and its cultivation extracts or biomasses. Mushroom β-glucans are recognized by their potential effects as immunostimulants and immunosuppressants. They are highlighted as anticholesterolemic, anti-inflammatory, adjuvant in diabetes mellitus, mycotherapy for cancer treatment, as well as adjuvants for COVID-19 vaccines. Due to their relevance, several techniques of β-glucans extraction, purification, and analysis have already been described. Despite the previous knowledge of β-glucans' benefits for human nutrition and health, the main information about this topic refers to the molecular identification, properties, and benefits, as well as their synthesis and action on cells. Studies on biotechnology industry applications (product development) and the registered products of β-glucans from mushrooms are still limited and more common for feed and healthcare. In this context, this paper reviews the biotechnological production of food products containing β-glucans from basidiomycete fungi, focusing on food enrichment, and presents a new perspective on fungi β-glucans' use as potential immunotherapy agents. KEY POINTS: • Mushrooms' β-glucans for product development in the biotechnology industry • Biotechnological production of food products containing mushrooms' β-glucans • Basidiomycete fungi β-glucans are used as potential immunotherapy agents.

Anti-Cancer Potential of Edible/Medicinal Mushrooms in Breast Cancer

Edible/medicinal mushrooms have been traditionally used in Asian countries either in the cuisine or as dietary supplements and nutraceuticals. In recent decades, they have aroused increasing attention in Europe as well, due to their health and nutritional benefits. In particular, among the different pharmacological activities reported (antibacterial, anti-inflammatory, antioxidative, antiviral, immunomodulating, antidiabetic, etc.), edible/medicinal mushrooms have been shown to exert in vitro and in vivo anticancer effects on several kinds of tumors, including breast cancer. In this article, we reviewed mushrooms showing antineoplastic activity again breast cancer cells, especially focusing on the possible bioactive compounds involved and their mechanisms of action. In particular, the following mushrooms have been considered: Agaricus bisporus, Antrodia cinnamomea, Cordyceps sinensis, Cordyceps militaris, Coriolus versicolor, Ganoderma lucidum, Grifola frondosa, Lentinula edodes, and Pleurotus ostreatus. We also report insights into the relationship between dietary consumption of edible mushrooms and breast cancer risk, and the results of clinical studies and meta-analyses focusing on the effects of fungal extracts on breast cancer patients.

Food By-Products and Agro-Industrial Wastes as a Source of β-Glucans for the Formulation of Novel Nutraceuticals

Food and agro-industrial by-products provoke a great environmental and economic impact that must be minimized by adding value to these wastes within the framework of circular economy. The relevance of β-glucans obtained from natural sources (cereals, mushrooms, yeasts, algae, etc.), in terms of their interesting biological activities (hypocholesterolemic, hypoglycemic, immune-modulatory, antioxidant, etc.), has been validated by many scientific publications. Since most of these by-products contain high levels of these polysaccharides or can serve as a substrate of β-glucan-producing species, this work reviewed the scientific literature, searching for studies that utilized food and agro-industrial wastes to obtain β-glucan fractions, attending to the applied procedures for extraction and/or purification, the characterization of the glucans and the tested biological activities. Although the results related to β-glucan production or extraction using wastes are promising, it can be concluded that further research on the glucans' characterization, and particularly on the biological activities in vitro and in vivo (apart from antioxidant capacity), is required to reach the final goal of formulating novel nutraceuticals based on these molecules and these raw materials.

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.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

Application of Pressurized Liquid Extractions to Obtain Bioactive Compounds from Tuber aestivum and Terfezia claveryi

A PLE (pressurized liquid extraction) method was adjusted following a full-factorial experimental design to obtain bioactive-enriched fractions from Tuber aestivum and Terfezia claveryi. Temperature, time and solvent (water, ethanol and ethanol–water 1:1) parameters were investigated. The response variables investigated were: obtained yield and the levels of total carbohydrate (compounds, β-glucans, chitin, proteins, phenolic compounds and sterols). Principal component analysis indicated water solvent and high temperatures as more adequate parameters to extract polysaccharide-rich fractions (up to 68% of content), whereas ethanol was more suitable to extract fungal sterols (up to 12.5% of content). The fractions obtained at optimal conditions (16.7 MPa, 180 °C, 30 min) were able to protect Caco2 cells from free radical exposure, acting as antioxidants, and were able to reduce secretion of pro-inflammatory cytokines in vitro: IL-6 (50%), and TNFα (80% only T. claveryi ethanol extract), as well as reduce high inhibitory activity (T. aestivum IC50: 9.44 mG/mL).

Delivery of Phenolic Compounds, Peptides and β-Glucan to the Gastrointestinal Tract by Incorporating Dietary Fibre-Rich Mushrooms into Sorghum Biscuits

Sorghum biscuits were enriched with mushroom powders (Lentinula edodes, Auricularia auricula and Tremella fuciformis) at 5%, 10% and 15% substitution levels. An in vitro gastrointestinal digestion was used to evaluate the effect of this enrichment on the phenolic content and soluble peptide content as well as antioxidant activities of the gastric or intestinal supernatants (bio-accessible fractions), and the remaining portions of phenolic compounds, antioxidants and β-glucan in the undigested residue (non-digestible fraction). The phenolic content of the gastric and intestinal supernatants obtained from digested mushroom-enriched biscuits was found to be higher than that of control biscuit, and the phenolic content was positively correlated to the antioxidant activities in each fraction (p < 0.001). L. edodes and T. fuciformis enrichment increased the soluble protein content (small peptide) of sorghum biscuits after in vitro digestion. All mushroom enrichment increased the total phenolic content and β-glucan content of the undigested residue and they were positively correlated (p < 0.001). The insoluble dietary fibre of biscuits was positively correlated with β-glucan content (p < 0.001) of undigested residue. These findings suggested that enriching food with mushroom derived dietary fibre increases the bioavailability of the non-digestible β-glucan and phenolic compounds.

Modulation of human intestinal microbiota in a clinical trial by consumption of a β-D-glucan-enriched extract obtained from Lentinula edodes

PURPOSE

The aim of this study was to evaluate the hypocholesterolemic, immune- and microbiota-modulatory effect of a mushroom extract in hypercholesterolemic subjects.

METHODS

A randomized, controlled, double-blind, and parallel clinical trial was carried out with subjects from 18 to 65 years old (n = 52) with untreated mild hypercholesterolemia. Volunteers consumed a β-D-glucan-enriched (BGE) mixture (10.4 g/day) obtained from shiitake mushrooms (Lentinula edodes) ensuring a 3.5 g/day of fungal β-D-glucans or a placebo incorporated in three different commercial creams.

RESULTS

This mixture showed hypocholesterolemic activities in vitro and in animal studies. After eight weeks intervention, no significant differences in lipid- or cholesterol-related parameters were found compared to placebo subjects as well as before and after the BGE mixture administration. No inflammatory or immunomodulatory responses were noticed and no changes in IL-1β, IL-6, TNF-α or oxLDL were recorded. However, consumption of the BGE mixture was safe and managed to achieve the dietary fibre intake recommended as cardiovascular protective diet. Moreover, the BGE mixture modulated the colonic microbiota differently compared to placebo. Microbial community composition varied from before to after the intervention with several genera being positively or negatively correlated with some biomarkers related to cholesterol metabolism.

CONCLUSION

These results suggested a relation between cholesterol metabolism, microbiota and BGE administration. Nevertheless, the precise significance of this differential modulation was not fully elucidated and requires further studies.

Membrane Fractionation of Protein Hydrolysates from By-Products: Recovery of Valuable Compounds from Spent Yeasts

Spent brewer’s yeast (Saccharomyces sp.), the second most generated by-product from the brewing industry, contains bioactive and nutritional compounds with high added value such as proteins (40–50%), polysaccharides, fibers and vitamins. Molecules of interest from agro-industrial by-products need to be extracted, separated, concentrated, and/or purified so that a minimum purity level is achieved, allowing its application. Enzymatic hydrolysis has been successfully used in the production of peptides and protein hydrolysates. The obtained hydrolysates require efficient downstream processes such as membrane technology, which is an important tool for the recovery of thermolabile and sensitive compounds from complex mixtures, with low energy consumption and high specificity. The integration of membrane techniques that promote the separation through sieving and charge-based mechanisms is of great interest to improve the purity of the recovered fractions. This review is specifically addressed to the application of membrane technologies for the recovery of peptides from yeast protein hydrolysates. Fundamental concepts and practical aspects relative to the ultrafiltration of agro-industrial protein hydrolysates will be described. Challenges and perspectives involving the recovery of peptides from yeast protein hydrolysates will be presented and thoroughly discussed.

Isolation and comparison of α- and β-D-glucans from shiitake mushrooms (Lentinula edodes) with different biological activities

A polysaccharide-enriched extract obtained from Lentinula edodes was submitted to several purification steps to separate three different D-glucans with β-(1→6), β-(1→3),(1→6) and α-(1→3) linkages, being characterized through GC-MS, FT-IR, NMR, SEC and colorimetric/fluorimetric determinations. Moreover, in vitro hypocholesterolemic, antitumoral, anti-inflammatory and antioxidant activities were also tested. Isolated glucans exerted HMGCR inhibitory activity, but only β-(1→6) and β-(1→3),(1→6) fractions showed DPPH scavenging capacity. Glucans were also able to lower IL-1β and IL-6 secretion by LPS-activated THP-1/M cells and showed cytotoxic effect on a breast cancer cell line that was not observed on normal breast cells. These in vitro results pointed important directions for further in vivo studies, showing different effects of each chemical structure of the isolated glucans from shiitake mushrooms.

Effect of traditional and modern culinary processing, bioaccessibility, biosafety and bioavailability of eritadenine, a hypocholesterolemic compound from edible mushrooms

Eritadenine is a hypocholesterolemic compound that is found in several mushroom species such as Lentinula edodes, Marasmius oreades, and Amanita caesarea (1.4, 0.7 and 0.6 mg per g dry weight, respectively). It was synthesized during all developmental stages, being present in higher concentrations in the skin of shiitake fruiting bodies. When subjected to traditional cooking, grilling followed by frying were more adequate methodologies than boiling or microwaving to maintain its levels. Modern culinary processes such as texturization (with agar-agar) and spherification (with alginate) also interfered with its release. Grilling and gelling using gelatin enhanced eritadenine's bioaccessibility in an in vitro digestion model. An animal model (where male and female rats were administered 21 and 10 mg per kg animal per day of eritadenine) indicated that intake of the compound was safe under these concentrations; it reached the liver and reduced the atherogenic index (TC/HDL) in rat sera. Thus, it might be used to design a functional food.

In vitro and in vivo testing of the hypocholesterolemic activity of ergosterol- and β-glucan-enriched extracts obtained from shiitake mushrooms (Lentinula edodes)

Herein, two shiitake fractions were obtained: the ergosterol-enriched fraction exerted higher in vitro hypocholesterolemic activity and the β-glucan-enriched fraction reduced the cholesterol levels in mice.