The Effects of Subcritical Water Treatment on Antioxidant Activity of Golden Oyster Mushroom

The Effect of Green Extraction Technologies on the Chemical Composition of Medicinal Chaga Mushroom Extracts

The mushroom industry should implement green extraction technologies; however, there is not enough information on the differences between these techniques expressed as the chemical composition of the resulting extract. In this study, selected types of green extraction techniques (GETs) were used on Chaga (Inonotus obliquus) (Fr.) Pilát from Serbia (IS) and Mongolia (IM) to examine the differences that would enable the composition-based technology choices in the mushroom supplement industry. Subcritical water extraction (SWE), microwave-assisted (MW) extraction, and ultrasonic-assisted extraction (VAE) were used to prepare the extracts. SWE was performed at two different temperatures (120 and 200 °C), while 96% ethanol, 50% ethanol, and water were used for MW and VAE. The yield, the content of total phenols, total proteins, and carbohydrates, qualitative and quantitative analysis of phenolic compounds, carbohydrates, including α- and β- and total glucans, and fatty acids, were determined in the obtained extracts. SWE resulted in a significantly higher yield, total polysaccharide, and glucan content than any other technique. Glucose was the most dominant monosaccharide in the SWE samples, especially those extracted at 200 °C. The MW 50% EtOH extracts showed the highest yield of total phenols. Among the tested phenolic compounds, chlorogenic acid was the most dominant. SWE can be recommended as the most efficient method for extracting commercially important compounds, especially glucans and phenols.

Subcritical water extraction of Equisetum arvense biomass withdraws cell wall fractions that trigger plant immune responses and disease resistance

Plant cell walls are complex structures mainly made up of carbohydrate and phenolic polymers. In addition to their structural roles, cell walls function as external barriers against pathogens and are also reservoirs of glycan structures that can be perceived by plant receptors, activating Pattern-Triggered Immunity (PTI). Since these PTI-active glycans are usually released upon plant cell wall degradation, they are classified as Damage Associated Molecular Patterns (DAMPs). Identification of DAMPs imply their extraction from plant cell walls by using multistep methodologies and hazardous chemicals. Subcritical water extraction (SWE) has been shown to be an environmentally sustainable alternative and a simplified methodology for the generation of glycan-enriched fractions from different cell wall sources, since it only involves the use of water. Starting from Equisetum arvense cell walls, we have explored two different SWE sequential extractions (isothermal at 160 ºC and using a ramp of temperature from 100 to 160 ºC) to obtain glycans-enriched fractions, and we have compared them with those generated with a standard chemical-based wall extraction. We obtained SWE fractions enriched in pectins that triggered PTI hallmarks in Arabidopsis thaliana such as calcium influxes, reactive oxygen species production, phosphorylation of mitogen activated protein kinases and overexpression of immune-related genes. Notably, application of selected SWE fractions to pepper plants enhanced their disease resistance against the fungal pathogen Sclerotinia sclerotiorum. These data support the potential of SWE technology in extracting PTI-active fractions from plant cell wall biomass containing DAMPs and the use of SWE fractions in sustainable crop production.

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.

Antioxidant and Skin Whitening Activities of Sub- and Super-Critical Water Treated Rutin

We focused on the functional components, antioxidant activity, skin-whitening, and anti-wrinkle properties of subcritical and supercritical water (SCW)-treated rutin. Rutin treatments were performed at the following temperature and pressure conditions: 200 °C/15 bar, 300 °C/100 bar, and 400 °C/250 bar. ABTS and DPPH radical scavenging activities and reducing power presented their highest values (1193.72 mg AAE/g, 728.73 mg AAE/g, and 0.65, respectively) at 300 °C/100 bar. The tyrosinase inhibitory activity of SCW-treated rutin was 21.72–60.05% at 1 mg/mL. The ethyl acetate fraction showed 14.91% melanin inhibitory activity at a concentration of 10 µg/mL compared to the α-MSH treatment group. The protein expression inhibition rates of MITF, tyrosinase, TRP-1, and TRP-2 in the ethyl acetate fractions were 14.05%, 72%, 93.05%, and 53.44%, respectively, at a concentration of 10 µg/mL, compared to the control. These results indicate that SCW treatment could be used to develop cosmetic materials and functional food with physiological activity, and that SCW-treated rutin can be used as a skin-whitening cosmetic material.

Effect of subcritical water extraction conditions on the activity of alcohol metabolizing enzymes, ACE inhibition, and tyrosinase inhibition in Protaetia brevitarsis larvae

In order to develop processing methods with high physiological activity for Protaetia brevitarsis larvae (PBL), subcritical water (SCW) extraction was applied. The dried powder (1 g) of PBL was extracted with 10 mL distilled water at 100, 200, and 300 °C for 30 min. The SCW treatment significantly (p < 0.05) increased some physiological activities of the PBL extracts. The SCW extract at 300 °C increased alcohol dehydrogenase, acetaldehyde dehydrogenase, and tyrosinase inhibitory activities from 192.3 ± 4.1% to 452.2 ± 0.5%, 125.4 ± 2.9% to 153.3 ± 0.4%, and - 7.0 ± 0.7% to 26.1 ± 1.4%, respectively, compared to the extract at 100 °C. Contrarily, the inhibition activity of angiotensin converting enzyme was the highest at 200 °C. These results suggest that SCW is a suitable method to extract and maintain the physiological activity of PBL.

Autohydrolysis of Lentinus edodes for Obtaining Extracts with Antiradical Properties

The autohydrolysis of Lentinus edodes was proposed for the extraction of components with antioxidant properties. Operation under non-isothermal conditions was evaluated and compared with isothermal heating. The influence of process severity was assessed in the range of 0.18 to 4.89 (temperature between 50 and 250 °C), up to 80% (d.b.) The influence of process severity during the autohydrolysis of Lentinus edodes was assessed in the range -0.3 to 4.89 (temperature between 50 and 250 °C). Up to 80% (d.b.) of the initial raw material could be solubilized at 210 °C. The different behavior of the saccharide and phenolic fractions was observed with the treatment temperature. Whereas the highest concentration of the saccharide components (mainly glucooligosaccharides) was found at 210 °C, the maximum phenolic yield was identified at 250 °C. The phenolic content and the antiradical properties of the extract showed a continuous increase with the temperature range studied, and at 250 °C, showed antiradical properties comparable to synthetic antioxidants. Autohydrolysis liquid fractions were used as solvents in the formulation of bioactive starch-based hydrogels, identifying a positive correlation between the gel softening and the extracts' bioactivity features.

The mycelium of the Trametes versicolor (Turkey tail) mushroom and its fermented substrate each show potent and complementary immune activating properties in vitro

BACKGROUND

The medicinal mushroom Trametes versicolor (Tv, Turkey Tail) is often prepared for consumption as a powder from the fungal mycelium and the fermented substrate on which it grew. The goal for this study was to evaluate the immune-modulating properties of the mycelium versus the fermented substrate, to document whether an important part of the immune-activating effects resides in the metabolically fermented substrate.

METHODS

Tv mycelium was cultured on rice flour. The mycelium and the fermented substrate were mechanically separated, dried, and milled. The initial substrate served as a control. Aqueous fractions were extracted and passed through 0.22-μm filters. The remaining solids were passed through homogenization spin columns without filtration. The aqueous and solid fractions of the initial substrate (IS), the fermented substrate (FS), and the Trametes versicolor mycelium (TvM) were tested for immune-activating and modulating activities on human peripheral blood mononuclear cell cultures, to examine expression of the CD69 activation marker on lymphocytes versus monocytes, and on the T, NKT, and NK lymphocyte subsets. Culture supernatants were tested for cytokines using Luminex arrays.

RESULTS

Both aqueous and solid fractions of TvM triggered robust induction of CD69 on lymphocytes and monocytes, whereas FS only triggered minor induction of CD69, and IS had no activating effect. The aqueous extract of TvM had stronger activating effects than the solid fraction. In contrast, the solid fraction of IS triggered a reduction in CD69, below levels on untreated cells. Both aqueous and solid fractions of FS triggered large and dose-dependent increases in immune-activating pro-inflammatory cytokines (IL-2, IL-6), anti-inflammatory cytokines Interleukin-1 receptor antagonist (IL-1ra) and Interleukin-10 (IL-10), anti-viral cytokines interferon-gamma (IFN-γ) and Macrophage Inflammatory Protein-alpha (MIP-1α), as well as Granulocyte-Colony Stimulating Factor (G-CSF) and Interleukin-8 (IL-8). TvM triggered more modest cytokine increases. The aqueous extract of IS showed no effects, whereas the solid fraction showed modest effects on induction of cytokines and growth factors.

CONCLUSION

The results demonstrated that the immune-activating bioactivity of a mycelial-based medicinal mushroom preparation is a combination of the mycelium itself (including insoluble beta-glucans, and also water-soluble components), and the highly bioactive, metabolically fermented substrate, not present in the initial substrate.

Pressurized hot water extraction of β-glucans from Cantharellus tubaeformis

Cantharellus tubaeformis was processed by pressurized hot water extraction (80-240°C) with the aim of maximizing the extraction of oligomeric fractions, β-glucans, and the in vitro antioxidant properties of the extracts. Increased severity of treatment enhanced the extraction yields above 62% at temperatures of 210ºC or higher, corresponding to the maximum β-glucan yields. The highest antioxidant capacity was obtained at 170ºC, although the highest content of phenolic compounds was obtained at the highest severity studied. This hydrothermal treatment can be considered a suitable process to obtain extracts with antioxidant properties and rich in β-glucans.

Subcritical Water Technology for Extraction of Phenolic Compounds from Chlorella sp. Microalgae and Assessment on Its Antioxidant Activity

Chlorella sp. microalgae is a potential source of antioxidants and natural bioactive compounds used in the food and pharmaceutical industries. In this study, a subcritical water (SW) technology was applied to determine the phenolic content and antioxidant activity of Chlorella sp. This study focused on maximizing the recovery of Chlorella sp. phenolic content and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay as a function of extraction temperature (100–250 °C), time (5–20 min) and microalgae concentration (5–20 wt. %) using response surface methodology. The optimal operating conditions for the extraction process were found to be 5 min at 163 °C with 20 wt. % microalgae concentration, which resulted in products with 58.73 mg gallic acid equivalent (GAE)/g phenolic content and 68.5% inhibition of the DPPH radical. Under optimized conditions, the experimental values were in close agreement with values predicted by the model. The phenolic content was highly correlated (R² = 0.935) with the antioxidant capacity. Results indicated that extraction by SW technology was effective and that Chlorella sp. could be a useful source of natural antioxidants.