Aluminium in wild mushrooms and cultivated Agaricus bisporus

 The aluminium content in wild mushrooms (n = 271, 19 species) and in cultivated Agaricus bisporus (n = 15) was determined by graphite furnace atomic absorption spectroscopy. With an aluminium content of 30 – 50 μ/g dry matter (DM) Boletus and Xerocomus species, the most well-known and most popular mushrooms, proved to be poor in aluminium. Several species of the genus Suillus, Macrolepiota rhacodes, Hypholoma capnoides as well as individual samples of Russula ochroleuca and Amanita rubescens contained high aluminium concentrations of about 100 μg/g DM and more. Cultivated Agaricus bisporus had the lowest aluminium content, i. e. 14 μg/g DM. The site, its geological origin as well as the mushroom species influenced the aluminium content in the fruitbodies: these factors require further investigation. Mushrooms do not contribute significantly to aluminium intake by humans. Received: 23 January 1997     

Textural Changes in Mushrooms (Agaricus bisporus) Associated with Tissue Ultrastructure and Composition

The objective of this study was to determine ultrastructural and compositional changes in fresh mushrooms associated with adverse changes in texture during 9 d of post‐harvest storage at 12 °C. Mushroom softening (2.6N to 1.5N, puncturing force) was consistent with toughening (19.2N to 33.0N, gumminess). Protein and total carbohydrate content declined, but chitin content increased during mushroom storage. Most polysaccharides were extracted after deacetylation and depolymerization of chitin, indicating that structural glucans were mainly bound with acetylglucosamine polymers. Softening paralleled expansion of intercellular space at the pilei surface, hyphae shrinkage, central vacuole disruption, and loss of proteins (r = 0.94) and polysaccharides (r = 0.84), while toughening was associated with increased chitin content (r = 0.95).     

Acid and EDTA blanching effects on the essential element content of mushrooms (Agaricus bisporus)

Many chemicals such as citric acid, ascorbic acid hydrogen peroxide and ethylene diamine tetraacetic acid (EDTA) have been used as browning inhibitors as well as to control spoilage during storage and canning operations. In this study, four essential mineral elements were determined in fresh and blanched mushrooms (Agaricus bisporus). The effects of citric acid and EDTA blanching on the copper, zinc, iron and manganese content of mushrooms were investigated. Statistical analysis indicated that the differences in Fe, Cu, Mn and Zn levels between fresh and blanched mushrooms were not significant for citric acid blanching. However, mushrooms blanched with EDTA solutions contained significantly lower concentrations of Fe and Cu than those found in fresh mushrooms on a dry weight basis. © 2000 Society of Chemical Industry     

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.     

Recent advances in extending the shelf life of fresh Agaricus mushrooms: a review

Postharvest browning of Agaricus mushrooms is a severe problem that reduces the shelf life of harvested mushrooms because of their continued respiration and biochemical activity. There are no simple answers and no single treatment is known to limit overall quality deterioration. However, there are several strategies that are being implemented in order to reduce the rate of respiration for mushrooms. Packaging technology is the common denominator that allows us to implement these strategies and thus is key to quality preservation. In this review, first, the major factors involved in postharvest quality deterioration are discussed and then technological advances/methods used to counteract these hurdles are presented. Copyright © 2010 Society of Chemical Industry     

Qualitative changes in Pleurotus ostreatus (Jacq.: Fr.) Kumm. mushrooms resulting from different methods of preliminary processing and periods of frozen storage

BACKGROUND: The aim of this study was to investigate the effect of different methods of preliminary processing and periods of frozen storage on the quality of Pleurotus ostreatus (Jacq.: Fr.) Kumm. mushrooms. In pre‐processing, mushrooms were blanched or soaked and blanched in water as well as in aqueous solutions of citric acid, L ‐ascorbic acid and/or lactic acid. During 12 months of storage at ?25 °C, sensory evaluations, instrumental colour measurements and chemical analyses of the frozen products were carried out every 4 months. RESULTS: The greatest changes resulting from technological treatment were found in flavour. At the end of the storage period the content of thiamine and riboflavin decreased by 14–65% and 3–13% respectively compared with the raw material. This was accompanied by changes in total acidity and vitamin C content within the ranges ? 56 to + 61% and ? 97 to + 5% respectively. CONCLUSION: Based on the results of the sensory evaluation, a maximum storage period of 4 months was set for the frozen product obtained from unblanched mushrooms. Mushroom products pre‐processed in aqueous solutions with added substances may be stored for 8 months and those blanched in water for 12 months. Copyright © 2009 Society of Chemical Industry     

Contents of sugars,free amino acids and free 5′-nucleotides in mushrooms,Agaricus bisporus,during post-harvest storage

Common mushrooms, Agaricus bisporus (Lange) Imbach, were stored at 12 °C for 12 days and composition changes were examined during post-harvest storage. The contents of total sugars, mannitol and fructose decreased steadily during storage, whereas the content of other reducing sugars, excluding fructose, remained constant. The content of total free amino acids increased from 77.92 at day 0 to 140.57 g kg⁻¹ at day 6, and then slightly increased to 151.65 g kg⁻¹ at day 12. The contents of nine amino acids increased over time, of these glutamic acid was the most significant. The content of monosodium glutamate-like components increased from 22.67 at day 0 to 47.12 g kg⁻¹ at day 12. However, the contents of sweet and bitter components increased comparably from 24.08 and 24.17 at day 0 to 47.15 and 50.75 g kg⁻¹ at day 12, respectively. Total 5′-nucleotide content peaked at day 3. The contents of three flavour 5-nucleotides were high at days 3 and 6. © 1999 Society of Chemical Industry     

Effects of UV‐C irradiation on the physiological and antioxidant responses of button mushrooms (Agaricus bisporus) during storage

Novel postharvest technology not only preserves the freshness of fruits and vegetables, but also triggers the biosynthesis of antioxidant compounds as a secondary response. This study examined the browning and antioxidant properties of button mushrooms (Agaricus bisporus) treated with UV‐C irradiation in combination with cold storage. Three sample preparation methods for antioxidant activity analysis, simulative gastrointestinal digestion (GAR), direct evaluation (QUENCHER) and traditional solvent extraction (TSE), were used to evaluate the samples, and followed analysing by both FRAP and ABTS assays. Broadly, the results indicated that, following an initial increase, UV‐C irradiation suppressed browning during a cold storage period of 18 days. And the total phenolic content of the treated mushrooms were higher than that of the control, while the ascorbic acid content decreased sharply during storage, and UV‐C treatment had negative effects on ascorbic acid content. Results from the QUENCHER and GAR methods showed that UV‐C treatment significantly increases the total antioxidant capacity (TAC) of mushrooms throughout the entire storage period, and have a larger magnitude than that of TSE method. In conclusion, the combination of UV‐C irradiation and cold storage showed great potential for improving mushroom quality as a new postharvest technology.     

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.     

食用牛肝菌抽提物最佳提取工艺的研究

以食用牛肝菌为原料,在单因素实验的基础上,采用正交实验,研究了外加蛋白酶和纤维素鸥辅助抽提凰味物质的最佳工艺。结果表明,最佳工艺条件为：液固比8（mL/g）、提取pH60酸性蛋白酶与纤维素酶酶活比400／150、水解温度60℃、水解时间90min。采用最佳工艺抽提牛肝菌,抽提物中总氮舍量1．519％,氨基氮含量0．300％,蛋向厢水钾率19．75％,固形物提取率28．89％。     

Effect of washing with citric acid and antioxidants on the colour and microbiological quality of whole mushrooms (Agaricus bisporus L.)

The effect of washing with citric acid followed by anti‐browning treatment involving rinsing with sodium d ‐isoascorbate or sodium l ‐ascorbate on the colour, microbiological quality and bacterial blotch of whole mushrooms when stored at 5 °C for up to 13 days at 80% RH was evaluated. Washing with 1% citric acid reduced Pseudomonas counts avoiding bacterial blotch, but caused an important deterioration of colour. When washing with citric acid was followed by an anti‐browning treatment, mushrooms colour was improved, at the same time as bacterial blotch was reduced, although the decrease of Pseudomonas counts was smaller than in mushrooms washed only with citric acid. The most effective treatment was washing with 1% citric acid followed by anti‐browning treatment with 1.5% sodium l ‐ascorbate.     

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.     

松茸、黑牛肝菌、双孢白蘑菇提取物体外抗氧化性试验研究

采用超氧阴离子、羟基自由基、卵磷脂脂质体体系以及测定还原力的方法,研究了松茸、黑牛肝茵、双孢白蘑菇3种食用菌,水提多糖、水提多酚、醇提多酚这3种不同提取方式,所得初提物的抗氧化试验,并测定各种处理的可溶性多糖及多酚含量.结果表明:醇提多酚具有最强的还原力,其中黑牛肝菌还原力最强;3种食用茵醇提多酚的清除超氧阴离子的能力较其他两种提取方式强;3种食用茵清除羟基自由基能力在醇提最大质量浓度下最强,分别达到59.00%、59.12%,57.19%,卵磷脂脂质体清除率分别达到:47.03%、37.84%,25.68%.     

采后钙处理对双孢菇贮藏生理的影响

以清水处理为对照（CK）,研究了低温（温度0～2℃、相对湿度90%～95%）条件下,不同浓度（0.5%、1.0%、2.0%）的氯化钙处理对采后双孢菇（Agaricus bisporus）贮藏生理的影响。结果表明,0.5%浓度的氯化钙处理能够有效的抑制超氧阴离子自由基（O2-）产生速率和脂氧合酶（LOX）的产生、提高过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）的活性,减少植物组织中多酚氧化酶（PPO）的产生;1.0%氯化钙处理能够提高POD的活性和降低PPO的活性,但对其他生理指标效果不明显;2.0%氯化钙处理效果不好,不能延缓双孢菇的衰老。综合考虑,0.5%氯化钙溶液处理能够有效的延缓双孢菇的采后衰老,在生产中具有广泛的应用价值。      

Microbiological quality and safety of fresh cultivated and wild mushrooms commercialized in Spain

402 samples of 22 species of cultivated and wild fresh mushrooms sold in retail markets and supermarkets in Zaragoza (Spain) were studied to quantify their microbial load (mesophilic aerobic microorganisms, Pseudomonas genus, Enterobacteriaceae, lactic acid bacteria, total and thermotolerant coliform bacteria, Escherichia coli, yeasts and moulds) and to investigate the presence of E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Yersinia enterocolitica. The total microbial counts ranged from 4.4 to 9.4 log cfu/g, the genus Pseudomonas being the most prevalent with counts from 3.7 to 9.3 log cfu/g and Auricularia auricula-judae the species with the highest microbial load (9.4 log cfu/g). No significant differences (p > 0.05) were detected between mean counts of wild and cultivated species in all the microbial groups studied. The microbiological safety level of the cultivated mushrooms was excellent since no pathogens were isolated, and the microbial counts of indicator microorganisms were low, being detected in only half of the species. Salmonella spp, E. coli O157:H7 and S. aureus were not isolated from any sample, Y. enterocolitica was detected in only four samples of wild mushrooms whereas twenty-six (6.5%) were positive for L. monocytogenes, their occurrence being relatively high in Calocybe gambosa (40%), Hygrophorus limacinus (40%) and Tuber indicum (100%). These results suggest that a strategy to reduce bacterial populations, and to improve the microbiological safety of some species of fresh mushrooms, should be investigated.     

Stipe Trimming at Harvest Increases Shelf Life of Fresh Mushrooms (Agaricus bisporus)

Trimming the stipe of cultivated mushrooms, Agaricus bisporus, from 35 mm to 5 mm from the cap immediately after harvest resulted in improved shelf life as indicated by reduced browning and slower cap opening. This effect was evident after 3 days storage at 12°C, and became more pronounced after 6 days. Trimming the stipes had no significant effect on postharvest respiration rate or bacterial growth; thus, the shelf life improvement was due to other factors. Stipe trimming reduced the weight (yield) of saleable mushrooms by about 10%; thus, shelf life improvement would need to offset any economic loss to growers to make this practice commercially feasible.     

Evaluation of biodegradable film packaging to improve the shelf-life of Boletus edulis wild edible mushrooms

The objective of this work was to evaluate the effect of poly(lactic acid) (PLA) based biodegradable film packaging combining 0.5% nisin antimicrobial polypeptide on the physicochemical and microbial quality of Boletus edulis wild edible mushrooms stored at 4 ± 1 °C. The experiment was set up by packaging mushrooms with extruded PLA films containing 0, 7.5, and 15 wt.% triethyl citrate plasticizer. The low-density polyethylene (LDPE) film was used as the control. Mushrooms stored in PLA films containing 7.5 and 15 wt.% plasticizer provided better retention of quality characteristics and received higher sensory ratings compared to mushrooms stored in pure PLA film and LDPE film. Samples with these two treatments underwent minimal changes in texture, PPO activity, total bacteria count, and sensory attributes. Results suggest that nisin in combination with plasticized PLA film has the potential to maintain B. edulis wild edible mushroom quality and extend its postharvest life to 18 days.Industrial relevanceB. edulis is one of the most commercialized mushrooms worldwide. However, as with all fresh mushrooms, there are severe preservation problems. Extruded PLA films containing triethyl citrate plasticizer plus antimicrobial agent nisin proved to be a suitable technology for mushroom conservation. This material exhibits an environmental-friendliness potential and a high versatility in food packaging.     

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     

Negative Regulation of Innate Immune Signaling by Components of the Button Mushroom Agaricus bisporus

Scope: Mushrooms are valued as an edible and medical resource for millennia. As macrofungi, they possess conserved molecular components recognized by innate immune cells like macrophages, yet unlike pathogenic fungi, they do not trigger the immune system in the same way. That these well-tolerated foods both avoid immuno-surveillance and have positive health benefits, highlights the dearth of information on the interactions of mushroom-derived products with the immune system. Methods and results: Using powders produced from the common white button mushroom, Agaricus bisporus, it is observed that pre-treatment of mouse and human macrophages with mushroom powders attenuates innate immune signaling triggered by microbial ligands like LPS and  β-glucans, including NFκB activation and pro-inflammatory cytokine production. This effect of mushroom powders is observed at lower doses of TLR ligands, suggesting a model of competitive inhibition whereby mushroom compounds bind and occupy innate immune receptors, precluding activation by microbial stimuli. This effect is preserved following simulated digestion of the powders. Moreover, in vivo delivery of mushroom powders attenuates the development of colitis in a DSS-mouse model. Conclusion: This data highlights an important anti-inflammatory role for powdered A. bisporus mushrooms, which can be further utilized to develop complementary approaches to modulate chronic inflammation and disease.