SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Agaricus

29

While mushrooms are the highest dietary source for the unique sulfur-containing antioxidant ergothioneine, little is known regarding levels of the major biological antioxidant glutathione. Thus, our objectives were to determine and compare levels of glutathione, as well as ergothioneine, in different species of mushrooms. Glutathione levels varied >20-fold (0.11-2.41mg/gdw) with some varieties having higher levels than reported for other foods. Ergothioneine levels also varied widely (0.15-7.27mg/gdw) and were highly correlated with those of glutathione (r=0.62, P<0.001). Both antioxidants were more concentrated in pileus than stipe tissues in selected mushrooms species. Agaricus bisporus harvested during the third cropping flush contained higher levels of ergothioneine and glutathione compared to the first flush, possibly as a response to increased oxidative stress. This study demonstrated that certain mushroom species are high in glutathione and ergothioneine and should be considered an excellent dietary source of these important antioxidants.

Concepts: Species, Antioxidant, Oxidative stress, Oxidative phosphorylation, Glutathione, Mushroom, Agaricus bisporus, Agaricus

28

The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. Thus, prolonging postharvest storage, while preserving their quality, would benefit the mushroom industry as well as consumers. There has been extensive research on finding the most appropriate technology for mushrooms preservation. Gamma, electron-beam and UV irradiation have been shown to be potential tools in extending the postharvest shelf-life of fresh mushrooms. Studies evaluating the effects of ionizing radiation are available mainly in cultivated species such as Agaricus bisporus, Lentinus edodes and Pleurotus ostreatus. This review comprises a comprehensive study of the effects of irradiation on physico-chemical parameters (weight, colour, texture and pH), chemical compounds including nutrients (proteins, sugars and vitamins) and non-nutrients (phenolics, flavonoids and flavour compounds), and on biochemical parameters such as enzymatic activity of mushrooms for different species and from different regions of the world.

Concepts: Ionizing radiation, Ultraviolet, Nutrition, Species, Mushroom, Agaricus bisporus, Agaricales, Agaricus

28

In the majority of sexual eukaryotes, the mitochondrial genomes are inherited uniparentally and have predominantly clonal population structures. In clonally evolving genomes, alleles at different loci will be in significant linkage disequilibrium. In this study, the associations among alleles at nine mitochondrial loci were analyzed for 379 isolates in four natural populations of the button mushroom Agaricus bisporus. The results indicated that the mitochondrial genome in the Desert California population was not significantly different from random recombination. In contrast, the three other populations all showed predominantly clonal mitochondrial population structure. While no evidence of recombination was found in the Alberta, Canada A. bisporus population, signatures of recombination were evident in the Coastal Californian and the French populations. We discuss the potential mechanisms that could have contributed to the observed mitochondrial recombination and to the differences in allelic associations among the geographic populations in this economically important mushroom.

Concepts: DNA, Gene, Genetics, Bacteria, Fungus, Mushroom, Agaricus bisporus, Agaricus

27

Browning is one of the most common postharvest changes in button mushrooms, which often results in economic losses. Phenolic compounds, which are associated with browning, were extracted from the non-bruised and bruised skin tissue of various button mushrooms with a sulphite containing solution and analysed with UHPLC-PDA-MS. In total, 34 phenolic compounds were detected. Only small differences in the total phenolic content between bruising-tolerant and sensitive strains were observed. The contents of γ-L-glutaminyl-4-hydroxybenzene (GHB) and γ-L-glutaminyl-3,4-dihydroxybenzene (GDHB) correlated with bruising-sensitivity, for example a R(2) of 0.85 and 0.98 was found for non-bruised brown strains, respectively. In non-bruised skin tissue of the strains with brown caps, the GHB and GDHB contents in sensitive strains were on average 20 times and 15 times higher, respectively, than in tolerant strains. GHB and GDHB likely participate in the formation of brown coloured GHB-melanin, which seemed the predominant pathway in bruising-related discoloration of button mushrooms.

Concepts: Fungus, Vegetarian cuisine, Basidiomycota, Mushroom, Agaricus bisporus, Agaricales, Agaricus, Agaricus campestris

27

Abstract In Hungary, fairly little is known about Agaricus subrufescens Peck (formerly called Agaricus blazei Murrill), which is cultivated on an industrial scale in the Far East. Nevertheless, this mushroom species exerts a curative influence and might become a new pillar of cancer research and antitumorous therapy. The present study gives a detailed discussion on the compositional differences of the scent components of A. subrufescens and its close relative Agaricus bisporus based on gas chromatography-mass spectrometry measurements, subsequent to Likens-Nickerson simultaneous distillation-extraction.

Concepts: Mushroom, Agaricus bisporus, Agaricus, Agaricus subrufescens

26

This study assessed the application of an antibrowning solution using vacuum impregnation (VI) and then electron-beam irradiation as a means to extend the shelf life of sliced white button mushrooms (Agaricus bisporus). A preliminary study helped to determine the best antibrowning solution and VI process parameters. Mushroom slices were impregnated with 2 g/100 g ascorbic acid + 1 g/100 g calcium lactate; 2 g/100 g citric acid + 1 g/100 g calcium lactate; 1 g/100 g chitosan + 1 g/100 g calcium lactate; and 1 g/100 g calcium lactate at different vacuum pressures and times and atmospheric restoration times. Selection of the antibrowning solution and VI parameters was based on texture and color of the mushroom slices. Next, the slices were irradiated at 1 kGy using a 1.35-MeV e-beam accelerator. Physicochemical, sensory, and microbial quality of mushrooms was monitored for 15 d at 4 °C. The best impregnation process in this study was 2 g/100 g ascorbic acid and 1 g/100 g calcium lactate at 50 mm Hg for 5 min and an atmospheric restoration time of 5 min. The control (untreated) samples suffered structural losses throughout storage. Only the vacuum impregnated-irradiated samples had acceptable color by the end of storage. Sensory panelists consistently preferred the samples produced with VI and irradiation because exposure to ionizing radiation inhibited growth of spoilage microorganisms.

Concepts: Acid, Food irradiation, E number, Mushroom, Agaricus bisporus, Agaricus

12

Previous studies on mushrooms suggest that they can be more satiating than meat, but this effect has not been studied with protein-matched amounts. The objective of this study was to assess the differences with satiety and ten-day food intake between A. bisporus mushrooms (226 g) and meat (28 g) in a randomized open-label crossover study. Thirty-two healthy participants (17 women, 15 men) consumed two servings of mushrooms or meat for ten days. On the first day, fasted participants consumed protein-matched breakfasts. Participants rated their satiety using visual analogue scales (VAS) at baseline and at regular intervals after the meal. Three hours later, participants were served an ad libitum lunch. Participants were given mushrooms or meat to consume at home for the following nine days. Energy intake was assessed at the ad libitum lunch, and participants also completed diet diaries on the day of the study, day 2, and day 10. Participants reported less hunger (p = 0.045), greater fullness (p = 0.05), and decreased prospective consumption (p = 0.03) after the mushroom breakfast. There were no significant differences in participant ratings of satisfaction (p = 0.10). There were also no statistically significant differences in energy intake at the ad libitum lunch or with the diet diaries from days 1 (p = 0.61), 2 (p = 0.77), or 10 (p = 0.69). Mushroom consumption did increase fiber intake on days 1, 2, and 10 but the difference in fiber consumption was only statistically significant on day 2 (p = 0.0001). The mushroom intervention also did not affect energy intake over the ten day feeding period.

Concepts: Nutrition, Statistical significance, Eating, Food, Basidiomycota, Mushroom, Agaricus bisporus, Agaricus

2

The effects of beef substitution with crimini or white mushrooms (Agaricus bisporus) on the flavor profiles of carne asada and beef taco blends were measured with a descriptive analysis panel. Sensory mitigation of sodium reduction through the incorporation of mushrooms was also investigated in the taco blends. The substitution of beef with mushrooms in the carne asada did not alter the overall flavor strength of the dish, but the incorporation of 50% or 80% ground mushroom in the beef taco blend did enhance its overall flavor as well as mushroom, veggie, onion, garlic and earthy flavors, and umami and sweet tastes. Overall flavor intensity of the 25% reduced-salt version of the 80% mushroom taco blend matched that of the full-salt versions of the 100% and 50% beef formulations, thus indicating that the substitution of 80% of the meat with mushrooms did mitigate the 25% sodium reduction in terms of the overall flavor impact of the dish, even if it did not quite compensate for the reduction in salty taste. This proof-of-concept study for the Healthy Flavors Research Initiative indicates that because of their flavor-enhancing umami principles, mushrooms can be used as a healthy substitute for meat and a mitigating agent for sodium reduction in meat-based dishes without loss of overall flavor.

Concepts: Taste, Vegetarian cuisine, Basidiomycota, Substitute good, Mushroom, Agaricus bisporus, Agaricus, Carne asada

1

True breeding of button mushrooms has hardly been done in the last decades, despite this species being one of the most cultivated mushrooms worldwide. Research done in the last 20 years has identified and characterised new germplasm and improved our understanding of the genetic base for some traits. A substantial collection of wild-collected strains is now available and partly characterised for a number of important traits such as disease resistance and yield. Most of the variations found in a number of important agronomic traits have a considerable heritability and are thus useful for breeding. Genetic marker technology has also developed considerably for this mushrooms in the last decade and used to identify quantitative trait loci (QTL) for important agronomic traits. This progress has, except for one example, not resulted so far into new commercially varieties. One of the reasons lies in the typical life cycle of the button mushroom Agaricus bisporus var. bisporus which hampers breeding. Joint investment is needed to solve technical problems in breeding. Special attention is needed for the protection of new varieties. Due to its typical life cycle, it is very easy to generate so called “look-a-likes” from protected cultivars by screening fertile single spore cultures. A consensus has been reached within the mushroom (breeding) industry to consider this method as the generation of essentially derived varieties as defined in plant breeding.

Concepts: Genetics, Fungus, Quantitative trait locus, Basidiomycota, Mushroom, Agaricus bisporus, Cultivar, Agaricus

1

The demand for button mushrooms of high quality is increasing. Superior button mushroom varieties require the combination of multiple traits to maximize productivity and quality. Very often these traits are correlated and should, therefore, be evaluated together rather than as single traits. In order to unravel the genetic architecture of multiple traits of Agaricus bisporus and the genetic correlations among traits, we have investigated a total of six agronomic and quality traits through multi-trait QTL analyses in a mixed-model. Traits were evaluated in three heterokaryon sets. Significant phenotypic correlations were observed among traits. For instance, earliness (ER) correlated to firmness (FM), cap color, and compost colonization, and FM correlated to scales (SC). QTLs of different traits located on the same chromosomes genetically explains the phenotypic correlations. QTL detected on chromosome 10 mainly affects three traits, i.e., ER, FM and SC. It explained 31.4 % phenotypic variation of SC on mushroom cap (heterokaryon Set 1), 14.9 % that of the FM (heterokaryon Set 3), and 14.2 % that of ER (heterokaryon Set 3). High value alleles from the wild parental line showed beneficial effects for several traits, suggesting that the wild germplasm is a valuable donor in terms of those traits. Due to the limitations of recombination pattern, we only made a start at understanding the genetic base for several agronomic and quality traits in button mushrooms.

Concepts: DNA, Gene, Genetics, Fungus, Basidiomycota, Mushroom, Agaricus bisporus, Agaricus