Selenium contents of Portuguese commercial and wild edible mushrooms

The selenium contents of 66 mushroom samples, wild growing or commercially available in Portugal, fresh, canned or dried, were determined. The samples consisted of 18 mushroom species, mainly selected in accordance with their availability and consumer preference. The selenium contents varied considerably between different mushroom species. The highest selenium contents were found in the wild species Boletus aestivalis (48.5 mg/kg dry weight, DW), Boletus pinophilus (19.9 mg/kg DW), Boletus edulis (14.9 mg/kg DW), Boletus aereus (12.3 mg/kg DW), Boletus fragans and Boletus spretus (∼2 mg/kg DW). Other mushrooms having considerable selenium contents included Marasmius oreades (1.5 mg/kg DW), Agaricus bisporus “Portobello” (1.25 mg/kg DW), A. bisporus (1.0 mg/kg DW) and Russula cyanoxantha (0.72 mg/kg DW). The selenium contents of these mushrooms are sufficient to provide nutritionally significant amounts in relation to the total daily intake of selenium. Other edible mushrooms, such as Lentinula edodes, Pleurotus ostreatus, Cantharellus cibarius,Craterellus cornucopioides and Lepista nuda, contained only small amounts of selenium. The importance of these mushrooms as a source of selenium is therefore marginal.     

Effect of damaged starch on acrylamide formation in whole wheat flour based Indian traditional staples, chapattis and pooris

Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.     

Chemical characterisation and speciation of organic selenium in cultivated selenium-enriched Agaricus bisporus

The selenium concentration in Agaricus bisporus cultivated in growth compost irrigated with sodium selenite solution increased by 28- and 43-fold compared to the control mushroom irrigated solely with water. Selenium contents of mushroom proteins increased from 13.8 to 60.1 and 14.1 to 137 μg Se/g in caps and stalks from control and selenised mushrooms, respectively. Selenocystine (SeCys; detected as [SeCys]₂ dimer), selenomethionine (SeMet), and methyl-selenocysteine (MeSeCys) were separated, identified and quantified by liquid chromatography–electrospray ionisation-mass spectrometry from water solubilised and acetone precipitated proteins, and significant increases were observed for the selenised mushrooms. The maximum selenoamino acids concentration in caps and stalks of control/selenised mushrooms was 4.16/9.65 μg/g dried weight (DW) for SeCys, 0.08/0.58 μg/g DW for SeMet, and 0.031/0.10 μg/g DW for MeSeCys, respectively. The most notable result was the much higher levels of SeCys accumulated by A. bisporus compared to SeMet and MeSeCys, for both control and selenised A. bisporus.     

Ultraviolet irradiation: The generator of Vitamin D2 in edible mushrooms

Fresh Shiitake mushrooms (Lentinula edodes), Oyster mushrooms (Pleurotus ostreatus), Button mushrooms (Agaricus bisporus), and Abalone mushrooms (Pleurotus cystidus) were irradiated with Ultraviolet-A (UV-A; wavelength 315–400 nm), Ultraviolet-B (UV-B; wavelength 290–315 nm), and Ultraviolet-C (UV-C; wavelength 190–290 nm). Irradiation of each side of the mushrooms for 1 h, was found to be the optimum period of irradiation in this conversion. The conversions of ergosterol to vitamin D₂ under UV-A, UV-B, and UV-C were shown to be significantly different (p < 0.01). The highest vitamin D₂ content (184 ± 5.71 μg/g DM) was observed in Oyster mushrooms irradiated with UV-B at 35 °C and around 80% moisture. On the other hand, under the same conditions of irradiation, the lowest vitamin D₂ content (22.9 ± 2.68 μg/g DM) was observed in Button mushrooms.     

Isolation and quantitative determination of ergosterol peroxide in various edible mushroom species

Ergosterol peroxide, the steroidal derivative with cytotoxic activity, has been isolated for the first time from the mycelium of edible and medicinal mushroom Hericiumerinaceum (lion’s mane mushroom) together with erinacine A. The new densitometric method was applied for the quantitative determination of ergosterol peroxide in n-hexane extracts of H. erinaceum, Laetiporus sulfureus (chicken mushroom), and Morchella esculenta (common morel) mycelia, as well as in Boletus edulis (king bolete), Suillus bovinus (Jersey cow mushroom), and B. badius (bay bolete) fruiting bodies. The ergosterol peroxide content reached 15.98 ± 0.78, 10.07 ± 0.75, 13.37 ± 0.56, 29.32 ± 1.43, 17.27 ± 0.84, and 12.60 ± 0.59 mg per 100 g, respectively. What is significant was that ergosterol peroxide was identified for the first time, to the best of our knowledge, in edible mushrooms mentioned above.     

Development, life table and thermal requirement of Tyrophagus putrescentiae (Astigmata: Acaridae) on mushrooms

The synanthropic mould mite, Tyrophagus putrescentiae infests various stored products, plant seeds and mushroom beds. Its biology was studied under controlled laboratory conditions at 10, 15, 20, 25, and 30 °C, 70% r.h. and a photoperiod of 16:8 (L:D) h when reared on button mushroom, Agaricus bisporus and oyster mushroom, Pleurotus ostreatus. Tyrophagus putrescentiae had a significantly shorter developmental time at 25 °C when reared on button mushroom compared with oyster mushroom and this time decreased with increasing temperature. The pre-oviposition period was not influenced by the species of mushroom, but the other reproductive periods showed significant changes and female longevity was influenced by food type. The sex ratio of the offspring (♀/♂) and female percentage were 1.16% and 53.7%, respectively. When reared on button mushroom at 25 °C, the net reproductive rate (R₀) for T. putrescentiae was 90.13 and the intrinsic rate of increase (r_m) was 0.196 which were significantly different from the 18.97 and 0.122, respectively, when reared on oyster mushroom. The doubling times were 3.74 and 5.62 days for the two mushroom types, respectively. The developmental thresholds for eggs, larvae, protonymphs and tritonymphs were 8.38, 8.01, 7.51 and 10.12 °C, respectively, and the thermal unit (degree-days) for all immature stages was 250.62 °C. Developmental thresholds of the various stages were significantly different.     

Characterisation of esterolytic activity from two wild mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum

Characterisation of esterase activities from the edible mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum, were investigated. Native electrophoresis of the crude extracts prepared from both mushroom samples showed the presence of esterolytic activities. The extracts had the greatest activity in the presence of p-nitrophenyl butyrate (pNPB) as a substrate. pH and temperature optima were found to be 8.0 and 30 °C for both enzymes, respectively. V_max and K_m values were determined as 14.2 U/l and 71 μM for A. vaginata var. vaginata and 34.6 U/l and 9.6 μM for T. terreum, respectively. The pH-stability profile showed a stationary line between 3.0 and 10.0 for both enzymes. The esterolytic activities from the extracts were maintained between 10 and 40 °C for 4 h and started to decrease at 50 °C. The effects of EDTA, NaN₃, DTT and PMSF on the enzyme activity were also investigated.     

Quantification of polyphenols and ergothioneine in cultivated mushrooms and correlation to total antioxidant capacity

Agaricus bisporus, Lentinula edodes, Pleurotus ostreatus, Pleurotus eryngii and Grifola frondosa were analyzed for antioxidant capacity, as measured by oxygen radical absorbance capacity (lipophilic and hydrophilic) (ORAC_total), hydroxyl radical averting capacity (HORAC), peroxynitrite radical averting capacity (NORAC), superoxide radical averting capacity (SORAC) assays, Folin-Ciocalteu reagent and ergothioneine (ERG) content. ORAC_totalvalues ranged from 39 to 138 μmol of Trolox equivalents (TE)/g dry weight (dw). HORAC values ranged from 3.0 to 13.6 μmol of caffeic acid equivalents/g dw. NORAC values ranged from 2.0 to 9.0 μmol TE/g dw. SORAC values ranged from 0.37 to 2.6 kunit superoxide dismutate equivalents/g dw. Polyphenols ranged from 4.2 to 10.6 mg gallic acid equivalents/g dw. A. bisporus mushrooms, especially portabellas, had higher antioxidant capacity relative to the specialty mushrooms tested. ERG ranged from 0.21–2.6 mg/g dw with L. edodes, P. ostreatus, G. frondosa containing a statistically significant greater amount compared to A. bisporus. A good correlation was found between ORAC_total and polyphenols (R² = 0.86).     

Non-volatile taste components of Agaricus blazei, Agrocybe cylindracea and Boletus edulis

Three species of dried mushrooms are commercially available in Taiwan, namely Agaricus blazei (Brazilian mushroom), Agrocybe cylindracea (black popular mushroom) and Boletus edulis (king bolete), and their non-volatile taste components were studied. All mushrooms were high in contents of carbohydrate, crude fiber and protein but low in contents of crude ash and fat. Arabitol, myo-inositol, mannitol and trehalose were detected in these three mushrooms, whereas glucose was not found in B. edulis. Contents of total soluble sugars and polyols ranged from 150.33 to 225.08 mg/g. Total free amino acid contents were low in these three mushrooms and ranged from 8.97 to 14.91 mg/g. The contents of MSG-like components ranged from 1.24 to 4.40 mg/g were in the descending order of the A. blazei, A. cylindracea and B. edulis. Total 5′-nucleotides contents of A. blazei and A. cylindracea were higher than that of B. edulis whereas flavor 5′-nucleotides content of A. blazei was higher than those of A. cylindracea and B. edulis. Equivalent umami concentrations values in three mushrooms ranged from 10.46 to 135.90 g per 100 g. Overall, these three mushrooms possessed highly umami taste.     

Mineralstoff- und Aminosäuregehalte des eßbaren,kultivierten Pilzes Shii-take (Lentinus edodes)

World wide about 200000 tons of shii-take mushrooms (Lentinus edodes) are produced per year. Different positive biological effects are known (anticarcinogenic, anticholesterol, immunostimulating effects), but the mineral contents and amino acid composition of caps and stipes are still little investigated. The concentrations of minerals are in general lower than those in the cultivated white mushroom (Agaricus bisporus) and in the oyster mushroom (Pleurotus ostreatus). The greatest differences are found in the concentrations of potassium, phosphorus, calcium, copper, strontium, manganese and zinc. The cocentrations are higher in caps than in stipes. The total amino acid content is 15,24% in caps and 11,35% in stipes (dry matter) and thus in general half of the concentration of cultivated champignon. The amounts of Phe, Gly, His, Arg, Ile and Met are relative higher than inAgaricus fruit bodies.     

Selected physical properties of chitin prepared from shiitake stipes

Fungal chitins were prepared from air-dried shiitake stipes by alkaline treatment and three decolorization methods. Yields of chitins A, B and C were 283.2, 367.2 and 250.8 mg/g, respectively. Three chitins were similar in the element profile due to their related N/C ratios. However, it seemed that the nitrogen content in chitin C was the highest (35.4 mg/g). Three chitins showed a melting endothermic peak at 248.65-248.92 °C, higher than stipes at 243.53 °C. The thermal decomposition enthalpies (ΔH) of chitins A and B were the same and higher than ΔH of chitin C and stipes. Under electron microscopic examination, shiitake stipes showed the aggregated flakes with dense and firm structure and without porosity whereas chitins were more compact than stipes. The major crystalline peak for three chitins was at 19.3-19.6° and three WAXD patterns were similar. Generally, three chitins prepared showed similar physical characteristics as evidenced by the element analysis, DSC, SEM and WAXD patterns.     

European elderberry (Sambucus nigra L.) rich in sugars,organic acids,anthocyanins and selected polyphenols

Sugars and organic acids in the fruit of two cultivars and three selections of black elderberry (Sambucus nigra L.): ‘Haschberg’, ‘Rubini’, ‘Selection 13’, ‘Selection 14’ and ‘Selection 25’ were quantified. The anthocyanin as well as quercetin profiles of this plant material were also established by the use of HPLC/MS. Significant differences in the concentration of sugars and organic acids were detected between the widely spread cultivar ‘Haschberg’ and all other cultivars/selections; ‘Haschberg’ was the richest in organic acids (6.38 g kg⁻¹ FW), and it contained the least sugar (68.5 g kg⁻¹ FW). The following major cyanidin based anthocyanins were identified in the fruit of black elderberry: cyanidin 3-sambubioside-5-glucoside, cyanidin 3,5-diglucoside, cyanidin 3-sambubioside, cyanidin 3-glucoside and cyanidin 3-rutinoside. The most abundant anthocyanin in elderberry fruit was cyanidin 3-sambubioside, which accounted for more than half of all anthocyanins identified in the berries. The ‘Rubini’ cultivar had the highest amount of the anthocyanins identified (1265 mg/100 g FW) and the lowest amount was measured in berries of the ‘Selection 14’ (603 mg/100 g FW). The ‘Haschberg’ cultivar contained a relatively low amount of anthocyanins in ripe berries (737 mg/100 g FW). From the quercetin group, quercetin, quercetin 3-rutinoside and quercetin 3-glucoside were identified; the latter prevailing in black elderberry fruit. The cultivar with the highest amount of total quercetins was ‘Selection 25’ (73.4 mg/100 g FW), while the ‘Haschberg’ cultivar contained average amounts of quercetins (61.3 mg/100 g FW). The chemical composition of the ‘Haschberg’ cultivar, the most commonly planted, conforms to the standards for sugars, anthocyanins and quercetins and exceeds them in the content levels of organic acids, the most important parameter in fruit processing.     

Evaluation of Penicillium expansum isolates for aggressiveness, growth and patulin accumulation in usual and less common fruit hosts

Experiments were carried out in vivo and in vitro with four isolates of Penicillium expansum (I 1, E 11, C 28 and I 12) to evaluate their aggressiveness, growth and patulin accumulation in both usual (pears and apples) and less common hosts (apricots, peaches, strawberries and kiwifruits) of the pathogen. The 75% of isolates showed the ability to cause blue mould in all tested hosts. In particular, C 28 and I 1 were the most and the least aggressive isolates, respectively (52.9 and 10.6% infection and 20.7 and 15.4 mm lesion diameters). ‘Candonga’ strawberries and ‘Pinkcot’ apricots showed the largest lesion diameters (29.8 and 25.3 mm), followed by ‘Conference’ pears, ‘Spring Crest’ peaches and ‘Abate Fetel’ pears. With the exception of ‘Candonga’ strawberries, the formation of colonies and mycelial growth of P. expansum isolates on fruit puree agar media (PAMs) was stimulated in comparison to a standard growth medium (malt extract agar, MEA). Two of the most aggressive isolates in our assays (I 12 and C 28) showed the greatest accumulation of patulin both in vitro and in vivo, while the least aggressive isolate (I 1) produced patulin only in a few growth media and cvs. Patulin concentration on fruit PAMs was higher than patulin detected in infected fruit tissues. Apple PAMs were the more favorable substrates for patulin accumulation in vitro (maximum concentration 173.1 and 74.1 μg/mL in ‘Pink Lady and ‘Golden Delicious’ PAMs, respectively) and ‘Pink Lady’ apples inoculated with the isolate E 11 showed the greatest accumulation of patulin in the whole in vivo assay (33.9 μg/mL). However, infected tissue of cv Golden Delicious showed lower average accumulation of patulin (1.7 μg/mL) than that of cv Pink Lady (19.1 μg/mL), and no significant differences in patulin concentrations were found among ‘Golden Delicious’ apples and tested cvs of pears, kiwifruits and strawberries. Peaches were highly susceptible to patulin accumulation, showing average concentrations of 27.4 and 18.6 μg/mL in vitro and in vivo, respectively. Apricots were also consistently positive for patulin accumulation, both in vitro (average values of 20.1 μg/mL) and in vivo (average values of 9.4 μg/mL). Our study showed the potential of some less common hosts of P. expansum (in particular peaches and apricots) to support patulin production, indicating that a steady monitoring of patulin contamination should be carried out in fruit substrates other than apples and pears.     

Pasting characteristics of fresh yams (Dioscorea spp.) as indicators of textural quality in a major food product – ‘pounded yam’

Low efficiency of available screening procedures constrains breeding and selection of yams (Dioscorea spp.) towards high textural quality of food products made from their tubers. This study was undertaken to determine the potential usefulness of pasting characteristics of fresh yams as rapid indicators of food textural quality in ‘pounded yam’, a staple food for millions of yam consumers, especially in West and Central Africa. Significant associations (P < 0.05) were found, through canonical correlation analysis, between pasting characteristics of fresh yams from six varieties, each, of Dioscorea rotundata and Dioscorea alata and the textural quality of pounded yam samples prepared from them. Good textural quality of pounded yam was associated with high peak viscosity, breakdown, final viscosity, holding strength and setback viscosity but with low pasting temperature in the fresh yam.     

Lentinus edodes heterogalactan: Antinociceptive and anti-inflammatory effects

Cold aqueous extraction of basidiocarps (fruiting bodies) of the edible mushroom Lentinus edodes (shiitake) gave rise to a heteropolysaccharide, whose chemical structure, antinociceptive and anti-inflammatory properties were determined. Its chemical structure was based on monosaccharide composition, methylation analysis, and NMR spectroscopy (¹H, ¹³C, HSQC, HSQC-TOCSY, HSQC-NOESY, and coupled HMQC). It was found to be a fucomannogalactan with a main chain of (1 → 6)-linked α-d-galactopyranosyl units, partially substituted at O-2 by single-unit β-d-Manp or α-l-Fucp side chains. The polysaccharide produced a marked and dose-related effect when assessed against acetic acid-induced visceral nociception. Prevention of peritoneal capillary permeability and leukocyte infiltration caused by the acetic acid was similar in potency and effectiveness.     

Short communication: Cultivation of Lentinus edodes mycelia using whey permeate as an alternative growth substrate

The major objective of this research was to use whey permeate as an alternative growth medium for the cultivation of mycelia of the edible mushroom Lentinus edodes and to find an optimum condition for solid-state cultivation. Response surface analysis was applied to determine the combination of substrate concentration (40 to 60 g of lactose/L), temperature (20 to 30°C), and pH (4 to 6) resulting in a maximal mycelial growth rate. The radial extension rates, estimated by measuring the diameters of growing colonies on the Petri dishes, were used as the growth rate of the mycelia at different conditions. The conditions predicted to maximize the mycelial growth of 6.41 ± 0.47 mm/d were determined to be 40 g of lactose/L, temperature 23.6°C, and pH 5.0. It was concluded that a partial cubic equation could accurately model the response surface of, and predict optimal growth conditions for, L. edodes mycelia using whey permeate because the model prediction agreed with the experimental growth rate, 6.39 ± 0.22 mm/d. The results suggest that whey permeate could be utilized as a growth substrate for the cultivation of mycelia from the edible mushroom L. edodes, enhancing the use of this by-product by the cheese manufacturing industry.     

Açaí (Euterpe oleraceae) ‘BRS Pará’: A tropical fruit source of antioxidant dietary fiber and high antioxidant capacity oil

This article reports a study of the concentrations of dietary fiber (DF) and antioxidant capacity in fruits (pulp and oil) of a new açaí (Euterpe oleraceae) cultivar—‘BRS-Pará’, with a view to determine the possibility of using it as a source of antioxidants in functional foods or dietary supplements. Results show that ‘BRS-Pará’ açaí fruits has a high content of DF (71% dry matter) and oil (20.82%) as well as a high antioxidant capacity in both defatted matter and oil. ‘BRS-Pará’ Açaí fruits can be considered as an excellent source of antioxidant dietary fiber. Antioxidant capacity of açaí ‘BRS-Pará’ oil by DPPH assay was higher (EC₅₀ = 646.3 g/g DPPH) than extra virgin olive oil (EC₅₀ = 2057.27 g/g DPPH). These features provide açaí ‘BRS-Pará’ fruits with considerable potential for nutritional and health applications.     

Evaluation of monosodium glutamate,disodium inosinate and guanylate umami taste by an electronic tongue

An electronic tongue (e-Tongue) was used to evaluate umami taste and compare different flavor enhancers (concentration and manufacture). Monosodium glutamate and three kinds of disodium inosinate and guanylate (I + G) were analyzed. The obtained data were analyzed by principal component analysis (PCA). The first principal component represented the intensity of umami taste. Based on Euclidean distance between ‘I + G’ samples and MSG (0.5%) on the PCA score plot, the umami intensity of all samples was ranked. The ‘I + G’ samples produced by three manufactures were successfully discriminated on the second principal component with a high discrimination index (82.26). Besides, the drift phenomenon of sensor was discussed and finishing sensor analyses in a continuous time could help avoid the drift. This study showed that e-Tongue was useful in analyzing the umami taste and might be a complementary tool in evaluation of flavor enhancer.     

Nonvolatile taste components of Grifola frondosa, Morchella esculenta and Termitomyces albuminosus mycelia

Three species of mushroom mycelia are commercially available in Taiwan, namely Grifola frondosa (maitake), Morchella esculenta (morel), and Termitomyces albuminosus (termite mushroom), and their nonvolatile taste components were studied. All mycelia were high in contents of carbohydrate, crude fat and protein but low in contents of crude ash and fiber. Arabitol, glucose, mannitol and trehalose were detected in these three mycelia and total amounts of sugars and polyols were 63.69-83.89 mg/g. Total free amino acid contents in three mycelia ranged from 35.67 to 50.37 mg/g. The monosodium glutamate-like components of G. frondosa mycelia (6.51 mg/g) was approximately twofold higher than M. esculenta and T. albuminosus mycelia (3.58 and 3.11 mg/g, respectively). As compared with other components, sweet and bitter components were much higher in these three mycelia. Contents of total 5′-nucleotides in these three mycelia ranged from 13.32 to 26.19 mg/g and were in the descending order of T. albuminosus>M. esculenta>G. frondosa. Equivalent umami concentration of T. albuminosus mycelia was higher than those of G. frondosa and M. esculenta mycelia. Overall, three mycelia possessed highly intense umami taste.     

Purification and characterisation of two enzymes related to endogenous formaldehyde in Lentinula edodes

In this study, γ-glutamyl transpeptidase (GGT) and l-cysteine sulphoxide lyase (C-S lyase) were purified from the fruiting body of Lentinula edodes in three steps and then characterised. We found that GGT together with C-S lyase caused the generation of endogenous formaldehyde in L. edodes. GGT was composed of a large subunit of 41 kDa and a small subunit of 25 kDa, and C-S lyase was composed of two identical subunits of 46 kDa, as determined by SDS–PAGE. GGT was stable at pH 8.0–10.0 with an optimum pH of 8.8, and was stable at 20–50 °C with an optimum activity at 37 °C. C-S lyase was stable at pH 8.0–9.0 with an optimum pH of 8.5, and was stable at 20–60 °C with an optimum activity at 40 °C. The present work supports the study of the mechanism of endogenous formaldehyde in L. edodes.