In this study, the antioxidant capacity of oyster mushroom (Pleurotus ostreatus) stored in five different temperature environments was investigated by DPPH (1,1 diphenyl‐2‐picryl hydrazyl) radical scavenging method. The antioxidant capacity results of oyster mushroom extracts were examined by spectroscopic measurements and expressed as percent of inhibition. The IC50 values of mushroom samples were calculated with DPPH method using calibration equations, and change in antioxidant properties was also tried to decipher by SEM images. The IC50 values of Pleurotus ostreatus for four different concentrations were also found in h+20°C > inh+4°C> inh−10°C> inh−20°C> inh−40°C, respectively. As a conclusion, the temperature factor of oyster mushroom in the range of −40°C to +20°C storage conditions is directly proportional to the change of antioxidant properties. The results have shown the importance of logistics and storage conditions in preserving the antioxidant properties of oyster mushroom and similar food samples.

In Turkey, forests cover almost 22.3 million ha of land, accounting for 28.6% of the total land area (GDF, 2015). The forested areas are mostly dominated by gymnosperms (almost 48% of the forested areas). Pine (Pinus spp.), juniper (Juniperus spp.), fir (Abies spp.), cedar (Cedrus spp.) and spruce (Picea spp.) are the major conifers grown in Turkish forests. The genus Abies includes over 50 species worldwide and is widespread throughout Europe, northern Africa, Asia and

Abstract:In this work Pleurotus ostreatus, Agaricus bisporus and Lactarius delicious were used to determine and compare their antioxidant capacities and metal contents. The edible mushroom samples were collected from Kastamonu in the West Black Sea region of Turkey. The antioxidant capacity studies were performed by DPPH (1, 1diphenyl-2-picryl hydrazyl) radical scavenging method and were expressed as Trolox equivalents with spectroscopic measurements. TEAC (Trolox Equivalent Antioxidant Capacity) values were found 0.302, 0.557 and 0.251 µM/g for Pleurotus ostreatus, Lactarius delicious and Agaricus bisporus, respectively. All samples were analyzed by X-ray fluorescence (XRF) spectrometry to obtain the concentration of Cr, Mn, Fe, Ni, Cu, Zn, Ca, Pb, Na, Mg and K. While maximum and minumum metal contents of mushrooms were found as mg/g for Na (96-14.9), Mg (8.83-2.60), K (4.05-3.16), Ca (0.089-0.019) and Fe (0.128-0.099), the maximum and minumum contents of mushrooms were found for Cr (8-5), , Zn (7-3) and Pb (3-1) as mg/kg. Metal contents were determined together with antioxidant capacity of all analysed mushrooms. It was observed that although the Fe, Ni, Ca, Na, and Mg contents of Agaricus bisporus were lower, it had got higher inhibition than the other mushroom species.

Background: Hydnum repandum, Cantharellus cibarius, Ramaria fennica, Boletus edulis, and Craterellus cornucopioides are all wild edible mushroom species from the Kastamonu province. The aim of this study was to investigate antioxidant properties and amino acid contents of these mushrooms. Materials and Methods: The mushrooms were analyzed for their free amino acid compositions using a high performance Amino Acid analyzer (Biochrom 30). Also, antioxidant activity and total phenolic concentrations of five different mushroom species were studied by using spectrophotometric methods. Results: The mushrooms contained 17 amino acids (g/100 g): Glutamic acid (2.56–1.11), Alanine (1.49–0.54), Arginine (1.62–6.77), Aspartic acid (1.45–0.81), Leucine (1.08–0.64), Methionine (1.05–0.06), Valine (1.05–0.66), Lysine (1.01–0.57), Serine (0.68–0.38), Cysteine (0.88–0.11), Isoleucine (0.61–0.39), Glycine (0.82–0.35), Threonine (0.82–0.44), Phenylalanine (0.66–0.42), Proline (0.60–0.47), Tyrosine (0.58–0.38), and Histidine (0.48–0.22). The total free amino acid (TAA) contents ranged from 169.2 mg/g in Boletus edulis to 89.1 mg/g in Hydnum repandum. These five different mushroom species contain eight essential amino acid species except tryptophan. The antioxidant activity of mushroom extracts was expressed as the percentage of DPPH radical inhibition and IC50 values (mg/mL). The percentage of inhibition ranged from 2.38% to 88.05% and IC50 values ranged from 0.03 to 13.98 mg/mL. The total phenolic content ranged from 0.66 to 7.74 mg/g of dry mushroom extract, expressed as gallic acid equivalents. Conclusion: Methanolic extract of Boletus edulis showed the highest phenolic content and strong antioxidant activity. As a result, the significant linear correlation between the values for the total phenolic content and antioxidant activity of mushroom extracts was corroborated in all of the investigated mushroom species, with the exception of Craterellus cornucopioides.

Antioxidant activities, metal contents, total phenolics and flavonoids were analyzed for Trametes versicolor and Laetiporus sulphureus collected from Kastamonu region by using ICP-OES and spectrophotometric methods. Antioxidant activity of mushroom extracts were expressed as percentage of DPPH radicals inhibition and IC50 values. Percentage of inhibition ranged from 15.83 to 61.03% and IC50 value was found 5.33 mg/mL for L. sulphureus and % inhibition ranged from 7.27 to 20.47% and IC50 value was found 18.10 mg/mL for T. versicolor. The content of phenols in methanolic extracts expressed in gallic acid equivalents varied between 77.41±1.10 and 272,70±2.26 mg/g for T. versicolor and L. sulphureus respectively. Also the content of flavonoids in methanolic extracts expressed in quercetin equivalents varied between 13.82±0.21 and 44.29±0.54 mg/mg for T. versicolor and L. sulphureus, respectively. As a result the significant linear correlation was corroborated between the values for the total phenolic content and antioxidant activity of this mushroom. In addition, all samples were analyzed by ICP-OES to obtain the concentration of Co, Cu, Cd, Pb, Ni, Cr, Na, Ca, Al, Fe, Zn, Ba, P, Mg, As, Mn and B. While maximum and minimum metal contents of mushrooms were found as mg/kg for Na (1.88-2.09), Mg (4.59-6.77), P (17.11-24.52), Ca (0.49-23.91) and Fe (0.49-3.84), the maximum and minimum trace metal contents of mushrooms were found as µg/kg for Cr (8.23-35.27), Ni (41.51-180.99), Cu (36.36-123.93).