Modification of the temporary maximum residue levels for mepiquat in cultivated fungi and oyster mushrooms

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant BASF SE submitted a request to the competent national authority in Finland to modify the temporary maximum residue level (MRL) to a permanent MRL for the active substance mepiquat in cultivated fungi (with a specific MRL for oyster mushrooms). The data submitted in support of the request (monitoring data from food business operators) are not sufficient to derive permanent MRL proposals. The assessment of these data, complemented by an analysis of the most recent monitoring data available from EU monitoring programmes, supports the conclusion that the existing t-MRL for cultivated fungi is still sufficient to account for the residue uptake in cultivated mushrooms other than oyster mushrooms. It was also noted that lower t-MRLs could be derived based on the assessment of the most recent monitoring data. A risk management decision is still needed on whether to maintain the existing t-MRL value. Regarding oyster mushrooms, EFSA derived different options for risk managers to eventually update the values of the temporary MRLs based on the most recent monitoring data from food business operators. Adequate analytical methods for enforcement are available to control the residues of mepiquat (expressed as mepiquat chloride) in the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the cross-contamination of untreated cultivated fungi (including oyster mushrooms) from cereal straw lawfully treated with mepiquat according to the current agricultural practices is unlikely to present a risk to consumer health.

Fine Mapping and Functional Analysis of the Gene PcTYR, Involved in Control of Cap Color of Pleurotus cornucopiae

Oyster mushrooms have a high biological efficiency and are easy to cultivate, which is why they are produced all over the world. Cap color is an important commercial trait for oyster mushrooms. Little is known about the genetic mechanism of the cap color trait in oyster mushrooms, which limits molecular breeding for the improvement of cap color-type cultivars. In this study, a 0.8-Mb major quantitative trait locus (QTL) region controlling cap color in the oyster mushroom Pleurotus cornucopiae was mapped on chromosome 7 through bulked-segregant analysis sequencing (BSA-seq) and extreme-phenotype genome-wide association studies (XP-GWAS). Candidate genes were further selected by comparative transcriptome analysis, and a tyrosinase gene (PcTYR) was identified as the highest-confidence candidate gene. Overexpression of PcTYR resulted in a significantly darker cap color, while the cap color of RNA interference (RNAi) strains for this gene was significantly lighter than that of the wild-type (WT) strains, suggesting that PcTYR plays an essential role in cap color formation. This is the first report about fine mapping and functional verification of a gene controlling cap color in oyster mushrooms. This will enhance our understanding of the genetic basis for cap color formation in oyster mushrooms and will facilitate molecular breeding for cap color. IMPORTANCE Oyster mushrooms are widely cultivated and consumed over the world for their easy cultivation and high biological efficiency (mushroom fresh weight/substrate dry weight × 100%). Fruiting bodies with dark caps are more and more popular according to consumer preferences, but dark varieties are rarely seen on the market. Little is known about the genetic mechanism of the cap color trait in oyster mushrooms, which limits molecular breeding for the improvement of cap color-type cultivars. A major QTL of cap color in oyster mushroom P. cornucopiae was fine mapped by using bulked-segregant analysis (BSA) and extreme-phenotype genome-wide association study (XP-GWAS) analysis. A candidate gene PcTYR coding tyrosinase was further identified with the help of comparative transcriptome analysis. qPCR analysis and genetic transformation tests proved that PcTYR played an essential role in cap color formation. This study will contribute to revealing the genetic mechanism of cap color formation in mushrooms, thereby facilitating molecular breeding for cap color trait.

Nutritional impact of adding a serving of mushrooms on usual intakes and nutrient adequacy using National Health and Nutrition Examination Survey 2011-2016 data

To evaluate the nutritional impact of adding a serving of mushrooms on usual intakes and population adequacy of nutrients the National Health and Nutrition Examination Survey (NHANES) 2011-2016 dietary data for 9-18 years and 19+ years and a composite of commonly consumed raw mushrooms as well as oyster mushrooms (nutrient profiles from USDA data) were used for modeling. Usual intakes of nutrients and the percent population below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) were estimated before and after addition of mushrooms. Means with nonoverlapping 95th percentile confidence levels were used to assess meaningful differences. Addition of a serving (84 g) of mushrooms to the diet resulted in an increase in dietary fiber (5%-6%), copper (24%-32%), phosphorus (6%), potassium (12%-14%), selenium (13%-14%), zinc (5%-6%), riboflavin (13%-15%), niacin (13%-14%), and choline (5%-6%) in both adolescents and adults; and in iron (2.32%), thiamin (4.07%), folate (3.66%), and vitamin B6 (4.64%) in adults only, but had no impact on energy, carbohydrate, fat, or sodium. Addition of a serving of mushrooms also decreased the % below EAR for copper, phosphorus, and riboflavin for those 9-18 years and for copper, phosphorus, selenium, zinc, thiamine, riboflavin, niacin, folate, and vitamin B6 for those 19+ years and increased the % above AI for potassium for both age groups. Addition of oyster mushrooms additionally increased 12%-13% vitamin D, and 12%-15% choline in the NHANES 2011-2016 diets. Addition of mushrooms exposed to UV light to increase vitamin D levels to 5 µg/serving also almost doubled vitamin D intake (98%-104%) and decreased inadequacy. Addition of a serving of mushrooms would also add 2.2 mg ergothioneine and 3.5 mg glutathione to the diet. Addition of a mushroom serving to the diet would increase several micronutrients including shortfall nutrients, without having any impact on energy, sodium, or fat.

Nutritional impact of adding a serving of mushrooms to USDA Food Patterns - a dietary modeling analysis

Mushrooms are part of vegetables and are important source of nutrients and bioactive compounds. The objective was to assess the nutritional impact of adding a serving of mushrooms in USDA Food Patterns using a similar approach to that used by USDA for Dietary Guidelines. A composite of commonly consumed raw mushrooms (white, brown/crimini and portabella; at 1:1:1 ratio) and raw speciality mushrooms (oyster mushrooms) were used for modeling. The United States Department of Agriculture (USDA) Food Data central database (https://fdc.nal.usda.gov/) was used to obtain nutrient profiles of mushrooms. Nutritional profiles of USDAs Food Patterns were obtained from the Scientific Report of the 2015 Dietary Guidelines Advisory Committee, Appendix E-3 (https://health.gov/dietaryguidelines/2015-scientific-report/15-appendix-E3/) and dietary modeling was accomplished by adding nutrients from mushrooms. Addition of an 84 g serving of commonly consumed raw mushrooms to USDA Food Patterns resulted in about 1% increase in calories, less than 5% increase in macronutrients, 2-3% increase in fiber, 8-12% increase in potassium, 12-18% increase in riboflavin, 11-26% increase in niacin, 11-23% selenium and 16-26% increase in copper depending upon the pattern type and calorie level. Mushrooms exposed to UV light to increase vitamin D levels to 200 IU/serving also increased vitamin D by 67-90% in USDA Food Patterns. Addition of oyster mushroom also additionally increased 8-11% vitamin D and 10-16% choline in USDA Food Patterns. Addition of mushrooms had minimal effect on sodium (1% or less increase) and no effect on saturated fat or cholesterol in USDA Food Patterns. Based on published data, a serving of commonly consumed mushrooms would also be expected to add 2.2 mg ergothioneine and 3.5 mg glutathione to the USDA Food Patterns. Addition of mushrooms to USDA Food Patterns increased several micronutrients including shortfall nutrients (such as potassium, vitamin D and choline), and had a minimal or no impact on overall calories, sodium or saturated fat.

Effect of the Intake of Oyster Mushrooms (Pleurotus ostreatus) on Cardiometabolic Parameters-A Systematic Review of Clinical Trials

Cardiometabolic diseases are a leading global health challenge. Their incidence as well as progression is strongly affected by diet. Consumption of Pleurotus ostreatus (P. ostreatus), an edible oyster mushroom rich in functional ingredients (e.g., β-glucans), may improve glucose and lipid metabolism, blood pressure, body weight and appetite sensations. Hence, this systematic review aimed to provide an overview on the effects of P. ostreatus intake on cardiometabolic parameters from clinical trials, taking into account risk of bias (RoB). Relevant studies were investigated for details with consideration of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The Cochrane Collaboration’s tool was used to assess the RoB. In total, eight trials included observed beneficial effects of P. ostreatus intake on glucose metabolism (reduction in fasting and/or 2 h postprandial glucose) and lipids (decrease in total cholesterol, LDL-cholesterol and/or triglycerides), and some found a reduction in blood pressure. In contrast, body weight did not change. Appetite sensations were not assessed. In most studies, the RoB was high or unclear due to methodological weaknesses and/or inadequate reporting. Thus, P. ostreatus intake may improve cardiometabolic health, but evidence for this is low. Hence, further clinical trials with an adequate study design are warranted to validate these suggestions.

Effects of Various Drying Methods on Some Physico-Chemical Properties and the Antioxidant Profile and ACE Inhibition Activity of Oyster Mushrooms (Pleurotus Ostreatus)

In food biotechnology, Pleurotus ostreatus is of great interest as a source of natural antioxidants and angiotensin-converting enzyme (ACE) inhibitors. However, research in this area has not yet been completed. The effect of various drying methods on the structural properties and the rehydration capacity of mushrooms was investigated in this paper. The content of secondary metabolites, the peptide profile, and the antioxidative effect and ACE inhibitory activity of dry mushrooms were investigated in vitro, simulating the process of gastrointestinal digestion. X-ray microtomography has confirmed that structure of lyophilic and sun-dried mushrooms is dominated by open pores, and in mushrooms dried with hot air and microwave, closed pores. Experiments have shown that the conditions of freeze drying and sun drying of Pleurotus ostreatus provide a higher rehydration capacity of dried mushrooms. The maximum activity of radical absorption of the oyster mushroom after microwave drying was observed. The iron restoring capacity of the mushrooms is maximally maintained with microwave drying and hot-air drying. The properties of the antioxidant product with an emphasis on the high activity of inhibiting lipid oxidation of the mushroom maximized after drying in the sun. Mushrooms dried lyophilically and in the sun showed the highest ACE inhibitory activity.

Polysaccharides from Basidiocarps of Cultivating Mushroom Pleurotus ostreatus: Isolation and Structural Characterization

Oyster mushrooms are an interesting source of biologically active glucans and other polysaccharides. This work is devoted to the isolation and structural characterization of polysaccharides from basidiocarps of the cultivated oyster mushroom, Pleurotus ostreatus. Five polysaccharidic fractions were obtained by subsequent extraction with cold water, hot water and two subsequent extractions with 1 m sodium hydroxide. Branched partially methoxylated mannogalactan and slightly branched (1→6)-β-d-glucan predominated in cold- and hot-water-soluble fractions, respectively. Alternatively, these polysaccharides were obtained by only hot water extraction and subsequent two-stage chromatographic separation. The alkali-soluble parts originating from the first alkali extraction were then fractionated by dissolution in dimethyl sulfoxide (DMSO). The polysaccharide insoluble in DMSO was identified as linear (1→3)-α-d-glucan, while branched (1→3)(1→6)-β-d-glucans were found to be soluble in DMSO. The second alkaline extract contained the mentioned branched β-d-glucan together with some proteins. Finally, the alkali insoluble part was a cell wall complex of chitin and β-d-glucans.

[The influence of the drying method for food properties and hypolidemic potential of oyster mushrooms (Pleurotus ostreatus)]

The aim of this research was to study the influence of two drying methods: freeze-drying sublimation and dry-air drying on the selected nutritional properties and hypolipidemic potential of fruiting bodies of oyster mushroom (Pleurotus ostreatus). The criteria for evaluation of the food properties were the color, the morphological structure, regidratation capacity, the total level of soluble proteins, fats, polysaccharides, free amino acids and monosaccharides. Lipid-lowering potential of oyster mushroom was evaluated by the concentration of lovastatin and the level of antioxidant activity. It has been experimentally revealed that the value of optical density of hydro-alcohol extracts of dried oyster mushrooms at a wavelength of 295 nm most clearly characterized its color which intensity was almost twice less in sublimated mushrooms, than шт the sample dried by dry-air method. Histological data showed that dry-air drying lead to the destruction of the mushroom cells and to the formation of a dense layered structure. Sublimation drying preserved the ordered cell structure and provided less deformation and shrinkage of the tissues. Using X-ray microtomography it was reported that freeze-dried mushrooms had uniform pore volume distribution. Dry-air dehydration method lead to the formation of larger cavities. The average percentage of the open pores was: 29.41±0.52% (after dry-air method), 11.10±0.41% (after freeze-drying method). Respectively the number of closed pores, which reflected the true value of porosity, was 0.99±0.01 and 1.75±0.01%. Structural differences of the samples of the dry oyster mushroom combined with their unequal hydration ability. Indicator of rehydration for oyster mushroom dried by sublimation method was 5.4±0.1, and for samples obtained by dry-air method it was 3.2±0.1. Respectively the average time of maximum water absorption was 22.7±1.8 and 45.3±2.9 minutes. It was found that the freeze-drying sublimation conditions were more conducive for the preservation of the biologically active protein and polysaccharide components of oyster mushrooms and on the other hand dry-air drying method increased the nutritional value of oyster mushrooms due to the reactions of polysaccharides autohydrolysis. The number of proteins and polysaccharides of the Oyster mushrooms samples dried by dry-air method and freeze-drying method was 72.0% and 56.0% respectively. Concentrations of free amino acids and glucose in the samples dried by freeze-drying and dry-air methods were 11.60±0.31%; 175.20±6.10 mg% and 7.00±0.28%; 144.0±5.7 mg% respectively. It has been experimentally recorded that the conditions of freeze drying were optimal in terms of ensuring the preservation of the content of natural statin and the antioxidant capacity of oyster mushrooms that provided its hypolipidemic potential. The amount of lovastatin in an the freeze-dried samples was 342±9.0 mg/kg, and was significantly higher than in the samples received by dry-air method - 190±6.0 mg/kg. The level of antioxidant activity of the oyster mushrooms samples were respectively 3.83±0.02 against 2.0±0.03 mmol/100 g. The conducted researches proved that for the production of dry oyster mushroom as a potential biologically active feedstock for the functional food products with lipid-regulating directivity the choice of the drying method had a fundamental importance.

Escaping introns in COI through cDNA barcoding of mushrooms: Pleurotus as a test case

DNA barcoding involves the use of one or more short, standardized DNA fragments for the rapid identification of species. A 648-bp segment near the 5' terminus of the mitochondrial cytochrome c oxidase subunit I (COI) gene has been adopted as the universal DNA barcode for members of the animal kingdom, but its utility in mushrooms is complicated by the frequent occurrence of large introns. As a consequence, ITS has been adopted as the standard DNA barcode marker for mushrooms despite several shortcomings. This study employed newly designed primers coupled with cDNA analysis to examine COI sequence diversity in six species of Pleurotus and compared these results with those for ITS. The ability of the COI gene to discriminate six species of Pleurotus, the commonly cultivated oyster mushroom, was examined by analysis of cDNA. The amplification success, sequence variation within and among species, and the ability to design effective primers was tested. We compared ITS sequences to their COI cDNA counterparts for all isolates. ITS discriminated between all six species, but some sequence results were uninterpretable, because of length variation among ITS copies. By comparison, a complete COI sequences were recovered from all but three individuals of Pleurotus giganteus where only the 5' region was obtained. The COI sequences permitted the resolution of all species when partial data was excluded for P. giganteus. Our results suggest that COI can be a useful barcode marker for mushrooms when cDNA analysis is adopted, permitting identifications in cases where ITS cannot be recovered or where it offers higher resolution when fresh tissue is. The suitability of this approach remains to be confirmed for other mushrooms.

Influence of low dose of gamma radiation and storage on some vitamins and mineral elements of dried oyster mushrooms (Pleurotus ostreatus)

Mushrooms contain some of the most potent natural medicines on the planet. Vitamins A, C, D, Mineral elements, contents, as well as total soluble solids (Brix^o) of dried composition of Pleurotus ostreatus were investigated after exposing to gamma radiation doses of 0 (control), 0.5, 1, 1.5, and 2 kGy at a dose rate of 1.7 kGy per hour in air from a Cobalt 60 source (SLL 515, Hungary) batch irradiator prior to storage (0 month) and after storage (12 months) at room temperature (28 ± 2°C). Results obtained showed some significant (p < .05) differences due to irradiation and storage. Before storage, vitamins A, C, and D contents of dried and irradiated mushrooms ranged 0.003 ± 0.08-0.014 ± 0.08, 0.042 ± 1.06-0.132 ± 1.06, and 0.040 ± 0.76-0.057 ± 0.76 mg/g, respectively. After 12 months, vitamin contents decreased and ranged 0.0029 ± 0.08-0.010 ± 0.08, 0.038 ± 1.06-0.125 ± 1.06, and 0.031 ± 0.76-0.05 ± 0.76 mg/g for vitamins A, C, and D, respectively. Total soluble solids recorded 1.5 Brix^o, however, showed no significant difference (p > .05) and did not change in 12 months after gamma irradiation up to 2 kGy. Sodium ranged from 14.00 ± 0.7 to 14.90 ± 0.8 mg/100 g. Potassium content varied from 30.20 ± 0.5 to 33.10 ± 0.6 mg/100 g. Magnesium content ranged 1.27 ± 0.15-3.53 ± 0.04 mg/100 g. Calcium ranged 11.00 ± 0.4-12.53 ± 0.4 ± 0.03 mg/100 g. Phosphorus content ranged 6.11 ± 0.30-6.41 ± 0.35 mg/100 g, whereas Nitrogen content was found to be 3.00 ± 0.03-3.60 ± 0.25 mg/100 g. Microelements or heavy metals included Copper; detected ranged 0.00 ± 0.00-0.02 ± 0.001 mg/100 g, Zinc content ranged 0.01 ± 0.002-0.03 ± 0.001 mg/100 g. Iron content was found to be in the range 0.29 ± 0.01-0.37 ± 0.1 mg/100 g. Manganese content was found to be in the range 0.03 ± 0.001-0.04 ± 0.01 mg/100 g. Lead content was found to be 0.00 ± 0.00-0.03 ± 0.001 mg/100 g. Food processing and storage has the potential to slightly alter the stability of vitamins in foods. Pleurotus ostreatus showed appreciable levels of mineral elemental composition, essential vitamins A, C, and D, and can be endorsed as a natural medicinal food product in the food and pharmaceutical industries. The heavy metals detected were with also below the upper limits permissible by the WHO standards and is thus safe for human consumption.