A Novel Functional Soy‐based Food Fermented by Lactic Acid Bacteria: Effect of Heat Treatment

ABSTRACT: The development of a novel fermented soymilk product using selected lactic acid bacteria was performed. The immunomodulatory properties of strains able to grow in soymilk were evaluated in a murine model using inbred BALB/c mice. Lactobacillus acidophilus CRL 43 and CRL 1064 and Lactobacillus paracasei CRL 75 and CRL 208 were all able to significantly increase the phagocytic index (41 ± 4) compared with the control group (16 ± 3) when given individually. These strains were then used in the elaboration of multicultured fermented soymilks that were able to stimulate an innate immune response (peritoneal macrophage activation). However, these novel fermented products sometimes caused undesired secondary effects such as microbial translocation and animal weight loss. When the same fermented products were subjected to heat treatment, they were still able to stimulate the innate immune response without causing secondary effects. These results clearly show that it is not always necessary for lactic acid bacteria to be alive to exert a beneficial physiological effect. This study could thus be used as a model in the design and future evaluation of novel fermented vegetable products.     

Postharvest Hardness and Color Evolution of White Button Mushrooms (Agaricus bisporus)

ABSTRACT: The quality evaluation of mushrooms was studied by storing fresh white button mushrooms (Agaricus bisporus) for 6 to 8 d, at various controlled temperature conditions (3.5 to 15 °C) and measuring the instrumental textural hardness and color of the mushroom cap for different product batches. A nonlinear mixed effect Weibull model was used to describe mushroom cap texture and color kinetics during storage considering the batch variability into account. Storage temperature was found to play a significant role in controlling texture and color degradation. On lowering storage temperature (i) the extent of the final browning extent in the mushroom after storage was reduced and (ii) the rate textural hardness losses was slowed down. A linear dependence of the final browning index with temperature was found. An Arrhenius type relationship was found to exist between the temperature of storage and storage time with respect to textural hardness. The average batch energy of activation was calculated to be 207 ± 42kJ/mol in a temperature range of 3.5 to 20 °C. Practical Application: This article evaluates how temperature abuse affects mushroom texture and color, applying methods that allow for the consideration of the natural product variability that is inherent in mushrooms. Its results apply to mushroom producers, retail distribution, and supermarkets for effective storage management.     

Immunomodulatory activities of mushroom sclerotial polysaccharides

The fight against cancer cells in the human body involves a defense system that is comprised of the innate and adaptive immunities which is controlled by a series of immune responses mediated by different immune cells and their secretory substances including cytokines and chemokines. Polysaccharides, especially those of fungal origin are well-known immunopotentiators that can boost up the immune system. Polysaccharides isolated from the fruit bodies and mycelia of both medicinal and edible mushrooms have been found to exert immunomodulatory function and antitumor activity in numerous in vivo and in vitro studies. In contrast, the potential of polysaccharides isolated from mushroom sclerotia as immunomodulators is only emerging. This paper gives a mini review on how the immunomodulatory actions of mushroom polysaccharides can eradicate tumor cells and also includes a recent study on the activation of innate immune cells and T-helper cells in normal and athymic BALB/c mice by three mushroom sclerotial polysaccharides with different structural characteristics extracted from Pleurotus tuber-regium and Polyporus rhinocerus.     

Heavy metal bioaccumulation by cultivated Agaricus bisporus from artificially enriched substrates

 Cultivated Agaricus bisporus possess the ability to bioaccumulate seven heavy metals (Pb, Cd, Hg, Fe, Cu, Mn, and Zn). The cultivated champignon mushroom A. bisporus was grown in soil composts of 16 different compositions. An edible mushroom, A. bisporus was also cultivated on humic compost artificially fortified with the seven heavy metals at five different concentrations (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10.0 mg/kg) and on control substrate (0 mg/kg) on a dry weight basis. The method of measuring bioaccumulation was flame atomic absorption spectrophotometry. Received: 1 October 1997 / Revised version: 19 January 1998     

The oviposition attractant for the mushroom phorid Megaselia halterata: The identification of volatiles present in mushroom house air

Neutral volatiles present in the air of a mushroom house during the spawn running phase of commercial production of the mushroom Agaricus bisporus have been identified and their source has been investigated. A group of polychloroanisoles emanated from broiler-house sweepings used in making wheat straw-chicken manure compost. Most of the straw volatiles were lost during the process of composting. With certain exceptions, most of the volatiles identified were metabolic products of A. bisporus, but the source of some cyclic monoterpenoids remains uncertain. Preliminary information suggests that some A. bisporus C₈ aliphatic alcohols and ketones are attractive to gravid females of the phorid Megaselia halterata.     

Biochemical changes associated with mushroom browning in Agaricus bisporus (Lange) Imbach and Pleurotus florida (Block & Tsao): commercial implications

Biochemical changes associated with mushroom browning in Agaricus bisporus and Pleurotus florida were studied. With increasing storage temperature from 0 to 25 °C there was an increase in phenol oxidase activity up to 15 °C followed by a decrease at 25 °C in both mushrooms. Loss of water content in fresh mushrooms had a direct relationship with phenol oxidase activity, which could be correlated with the visual degree of mushroom browning. A bisporus displayed higher phenol oxidase activity, about two to three times that of P florida. The phenol oxidase activity in both mushroom varieties was studied on a range of phenolic compounds with diverse functional groups. A bisporus exhibited intense reactions to tyrosine and catechol, while P florida did so to guaiacol and catechol. The two mushrooms differed in the degree of their oxidation reactions relative to the functional groups. In A bisporus the skin had more phenolics than the flesh; P florida contained fewer phenolics, while the stalks of both mushrooms had low phenolics contents. FTIR spectral studies of intact mushrooms during browning showed a characteristic decrease in phenolic hydroxyls; first‐derivative spectra were used to assess relative peak intensities. Of the chemicals tested for their effect on phenol oxidase activity, 0.1 M sodium carbonate favoured the immediate development of an orange chromogen in P florida, while mild alkaline solutions favoured the enzyme activity, and acidic solutions at the 0.1 M level completely inhibited the browning reaction in both mushrooms. Copyright © 2003 Society of Chemical Industry     

Optimum Measure of Cap Color in Agaricus bisporus Wild and Cultivated Strains

Cap color was characterized on a wide range of Agaricus bisporus strains. L, a and b tristimulus coordinates were tested by linear model analysis to determine color information related to each parameter. One model was retained: log(L/(100-L)) =α* H +β. Visual cap color variation was continuous and well described by log(L/(100-L)) or H parameters. In the wild, the range of color varied from white to dark brown which would enable mushroom breeding for cap color adapted to the market.     

Radical‐scavenging properties of extracts from the white button mushroom,Agaricus bisporus

BACKGROUND: Agaricus bisporus is the premier cultivated edible mushroom but is usually considered to be of lesser value nutritionally and medicinally compared with other cultivated mushrooms. The objective of this study was to investigate the radical‐scavenging properties of methanolic extracts and the free radical‐processing enzyme activities of water extracts from A. bisporus fruit bodies. Analyses were performed on total fruit bodies from three strains and on separated stipe, cap and gills from one strain, all cultivated experimentally under the same conditions. RESULTS: EC₅₀ values of scavenging ability on 1,1‐diphenyl‐2‐picrylhydrazyl radicals (DPPH^?), scavenging ability on 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cations (ABTS^?+) and reducing power of methanolic extracts from total fruit bodies ranged between 1.7 and 5.0 and were 1.1–1.9 times higher in a white hybrid than in two wild strains, cream and brown. The gills exhibited higher antioxidant activities relative to the stipe and cap. In water extracts, glutathione peroxidase activities were up to eight times higher than glutathione reductase activities and no difference was observed between strains. Catalase activity was highest in the brown wild strain. The only significant differences in free radical‐processing enzymes between the three parts of the mushroom were higher catalase activity in the gills and lower glutathione reductase activity in the stipe. CONCLUSION: The radical‐scavenging properties of the button mushroom are comparable to those of other edible mushrooms and dependent on the strain and on the section of the fruit body. Copyright © 2008 Society of Chemical Industry     

The sensory and microbiological quality of fresh sliced mushroom (Agaricus bisporus L.) packaged in modified atmospheres

The effect of modified atmospheres, generated by using different packaging films, on the quality of sliced mushrooms was evaluated. The carbon dioxide and oxygen content inside the packages as well as the colour, texture, weight loss, sensory attributes, mesophiles, psychrotrophs, Pseudomonas fluorescens, faecal coliforms, Escherichia coli and anaerobic spores were determined. Modified atmospheres containing 2.5% CO₂ and 10–20% O₂ reduced the microbial counts and improved the mushrooms’ appearance when compared with an air atmosphere. Modified atmospheres containing 15% CO₂ and <0.1% O₂ inhibited mushroom development and toughening and reduced microbial growth. Although these atmospheres had no effect on colour, they did allow the development of off odours and anaerobic spores were detected. No differences in microbial growth or mushroom spoilage were observed under the different moisture contents generated in the packages at 4 °C. Aerobic bacteria counts were considered very high even at the beginning.     

Comparison of Transesterification Methods for Fatty Acid Analysis in Higher Fungi: Application to Mushrooms

This study evaluated the effectiveness of two commonly used transesterification methods for the preparation of fatty acid methyl esters (FAMEs) for gas chromatographic analysis. A combination of base followed by acid catalysis [potassium hydroxide/sulfuric acid/methanol (KOH–H₂SO₄–MeOH)] was compared to an acid-only catalyst [methanolic–boron trifluoride (BF₃–MeOH)] for the quantification of the fatty acid content in mushrooms after preextraction of total lipids with chloroform/methanol (2:1 v/v). The mushrooms studied were commonly cultivated species, Agaricus bisporus (brown) and A. bisporus (white), and three wild medicinal mushrooms, turkey tail (Trametes versicolor), artist conk (Ganoderma applanatum), and tinder polypore (Fomes fomentarius). The major fatty acids identified were palmitic (C16:0), stearic (C18:0), oleic (C18:1), and linoleic acid (18:2n6) which constituted 80% to 90% of the total amount. Variation due to the FAME preparation methods was observed in both minor and major fatty acids. Another major observation made between the two methods was the total number of individual fatty acids (FAs) methylated. The base and acid transesterification procedure resulted in the identification of 42 FAMEs, whereas with the acid 38 FAMEs were observed. Therefore, the research recommends the use of a base–acid combination for preparation of FAMEs in mushroom lipids.     

Mushroom (Agaricus bisporus), Its Polyphenoloxidase, and Polyphenolics Affect In Vitro Iron Availability

In vitro iron availability (IA) from egg white meals was 14–17% of total meal iron. When mushroom (Agaricus bisporus) was added to egg white meals, IA decreased. The initially low IA from whey protein concentrate meals (<1% of meal iron) was enhanced by mushroom. Sodium benzoate or sodium bisulfite added to egg white/ mushroom meals increased IA. Addition of polyphenoloxidase (PPO) and gallic acid to egg white meals decreased IA; however, gallic acid alone increased IA. Blanching mushrooms eliminated PPO activity and increased IA of egg white/mushroom meals, but it was still less than for egg white meals. Sodium bisulfite added to blanched mushroom/egg white meals increased IA above that for egg white meals. Results are consistent with the interpretation that enzymatic browning can decrease IA.     

Effect of supplementing compost with grapeseed meal on Agaricus bisporus production

BACKGROUND: This work assesses the agronomic performance of grapeseed meal, before and after oil extraction, in nutritional compost supplement when growing the mushroom species Agaricus bisporus (Lange) Imbach. The effect of formaldehyde treatment before using this compost is also considered. Materials were applied at different doses at spawning. Along with non‐supplemented compost, three commercial nutritional supplements were used as controls. RESULTS: In general terms, grapeseed meal performance was similar to that of commercial delayed‐release nutrients, but improved the non‐supplemented compost response. We highlight that grapeseed enhances performance as larger yields of harvested mushrooms were obtained with greater dry weight content; however, their protein content was lower. The best performance was displayed by fresh formaldehyde‐treated grapeseed (6000 ppm) when applied to the 10 g kg^?1 compost dose. CONCLUSIONS: Our findings suggest that grapeseed meal offers a great potential to be applied on a commercial scale. The addition of grapeseed resulted in an enhanced performance as shown by the higher number of harvested mushrooms. The use of grapeseed meal (extracted or non‐extracted), a low‐cost ingredient with high levels of carbohydrates, may suppose an economic profit on the basis of the positive effect of adding carbon in the mushroom cultivation. Copyright © 2012 Society of Chemical Industry     

Evaluation of harvested mushrooms and viability of Agaricus bisporus growth using casing materials made from spent mushroom substrate

The present work evaluates of harvested mushroom and viability of Agaricus bisporus growth in several casing materials based on spent mushroom substrate. The experiment consisted of eight casing layer, which six were made with spent mushroom substrate. The results confirm the usefulness of reincorporating the spent substrate in new cultivation cycles as an ingredient of casing mixtures. In general, biological efficiency was high, three of the SMS based‐casings surpassing the threshold value of 100 kg 100 kg^?1 of compost. The high electrical conductivity of mixtures containing a large proportion of spent substrate limits the extent to which it can be used, although mixing it with other materials (such as peat) reduces these values to acceptable levels. In short, it makes economic and environmental sense to reuse spent mushroom substrate as an ingredient of alternative casing materials.     

Mushrooms and agaritine: A mini-review

Agaritine is a naturally occurring phenylhydrazine derivative present in wild and cultivated Agaricus mushroom species, including the cultivated mushroom Agaricus bisporus. Agaritine has been described in some studies as a potential carcinogen, however, the scientific validity of the experimental designs and models from which this conclusion has been drawn have been contradicted and challenged by other studies. Feeding studies using mushrooms and mushroom extracts have in general provided no evidence of toxicological effects of agaritine or mushroom consumption, in contrast to results of studies which have administered non-physiologically relevant concentrations of chemically synthesized hydrazine derivatives to mice. The available evidence to date suggests that agaritine from consumption of cultivated A. bisporus mushrooms poses no known toxicological risk to healthy humans.     

Heavy metal bioaccumulation by cultivated Agaricus bisporus from artificially enriched substrates

Cultivated Agaricus bisporus possess the ability to bioaccumulate seven heavy metals (Pb, Cd, Hg, Fe, Cu, Mn, and Zn). The cultivated champignon mushroom A. bisporus was grown in soil composts of 16 different compositions. An edible mushroom, A. bisporus was also cultivated on humic compost artificially fortified with the seven heavy metals at five different concentrations (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10.0 mg/kg) and on control substrate (0 mg/kg) on a dry weight basis. The method of measuring bioaccumulation was flame atomic absorption spectrophotometry.     

1-Octen-3-ol in the Cultivated Mushroom, Agaricus bisporus

Enzymatic formation of l-octen-3-ol in the cultivated mushroom, Agaricus bisporus, was studied. The optimal activity of lipoxygenase-hydroperoxide lyase enzymes for l-octen-3-ol formation was observed over the pH range 5.0 to 7.0. The highest amount of l-octen-3-ol was produced at pH 6.0. During the crop cycle, the l-octen-3-ol content of mushrooms varied from 19.3 to 37.2 ppm. More l-octen-3-ol was produced in the gills than other morphological tissues. During post-harvest storage at 12°C, enzyme activity as well as l-octen-3-ol content decreased dramatically over time.     

Amino Acid Content of Frozen Agaricus bisporus and Boletus edulis Mushrooms: Effects of Pretreatments

The effect of blanching or soaking and blanching on the amino acid content of frozen A. bisporus and B. edulis mushrooms was determined. Frozen mushrooms contained lower amounts of most amino acids compared to fresh mushrooms. In A. bisporus, the greatest changes were observed in mushrooms soaked and blanched in citric and L-ascorbic acid solution in A. bisporus, while in the case of B. edulis, mushrooms soaked and blanched in solution containing pectin showed the maximum change. Blanched-only products were significantly higher in asparagine, glutamine, isoleucine, and lysine than those that were soaked and blanched.     

Development of a Biosensor for Controlling of Thiourea in Fruit Juices

A simple and sensitive biosensor based on mushroom (Agaricus bisporus) tissue homogenate that contains polyphenol oxidase is described for the determination of thiourea. The mushroom tissue homogenate was immobilized to the sensitive top of a Clark-type oxygen electrode with gelatin and glutaraldehyde. The linear range of the system was 1–20 μM with a detection limit of 1 μM at pH 7.5 and 30 °C. The repeatability experiments were carried out, and the average value, standard deviation, and variation coefficient were calculated as 9.875 μM, ±0.279, and 2.83%, respectively. Interference studies revealed that the substances tested did not interfere with the biosensor. Finally, the proposed biosensor was applied to the determination of thiourea in fruit juices.     

The effect of superfine grinding on physicochemical properties of three kinds of mushroom powder

The effects of superfine grinding on apparent structure, physicochemical properties, and functional characteristics of three kinds of mushroom (Lentinus edodes, Hericium erinaceus, and Cordyceps militaris) powders were investigated. Coarse and 100-mesh powders of the mushrooms were prepared by common grinding, while a superfine powder was obtained by superfine grinding. By comparing the mushrooms before and after grinding, it was found that the mushroom fines did not produce new chemical groups but increased crystallinity. The results of the physicochemical properties revealed that the fines became less fluid after grinding. The protein content and solubility increased as the particle size decreased. The water and oil holding capacity, glucose binding capacity, cation exchange capacity, and antioxidant activity of the mushroom fines increased after grinding. This study provides a theoretical basis for the development process of edible mushroom food, as well as new ideas for the development of edible mushrooms.     

Determination of nutrients and volatile constituents of Agaricus bisporus (brown) at different stages

BACKGROUND: The physical properties, proximate composition, mineral and vitamin contents, and estimated volatile components of Portobello mushroom, Agaricus bisporus (brown), were analyzed in three flushes and at two different harvest times. The results showed different trends in the flushes and harvest terms studied. RESULTS: The mean values of texture, diameter, and protein of the harvested produce were 1.78–1.97 kg mm^?2, 4.67–5.02 cm, and 4.18–3.31% wet weight basis (wb), respectively. The mean Zn, Fe, P, Mg, K, Na, and Ca contents of both harvests (mg kg^?1 wb) were 8.15–7.07, 7.40–7.96, 1180.93–1038.69, 88.05–76.29, 213.29–238.82, 2652.0–2500.89, and 534.2–554.80, respectively. In terms of vitamin C, folic acid, thiamin, riboflavin, and niacin, the mean contents (mg kg^?1 wb) were 6.75–3.97, 0.09–0.08, 0.085–0.09, 0.27–0.29, and 3.62–2.94, respectively. The estimated volatile components comprised 18‐ or 16‐carbon compounds such as octadecanoic acid, hexadecanoic acid derivatives, and other important volatiles like dl‐limonene, n‐nonane, benzendicarboxylic acid, and cis‐linoleic acid esters. CONCLUSION: Nutritive contents and estimated volatiles of Portobello mushroom were evaluated in detail at different stages. Copyright © 2009 Society of Chemical Industry