Nutritional composition and antioxidant properties of selected edible wild mushrooms

Ten species of edible wild mushrooms that are commonly consumed by the locals were analyzed to determine their nutritional composition and antioxidant activity. Minerals content were determined by Flame Atomic and Graphite Furnace Spectrometry while vitamins were acquired by High Performance Liquid Chromatography. Fatty acid and amino acid profiles were determined by Gas Chromatography with flame ionization detector. Lentinellus omphallodes was found to have the highest content of protein (14% of dry weight), but low in fat (1.5%) and relatively a good source of fibre (14.8%). Potassium is the most abundant mineral in all mushroom samples analyzed, followed by magnesium and calcium. Sodium concentration was relatively low in all wild mushrooms. However, calcium content in Pleurotus cornucopiae is 10 times higher than the cultivated mushrooms. Overall, the trace element concentrations across all wild mushrooms were in the order Fe>Zn>Mn>Cu>Cr. The highest content of thiamin, riboflavin and ascorbic acid were found in Hygrocybe conica while the highest concentration for 0 - tocopherol was determined at 134.41 μg/g in Galiella ruta. Linoleic acid is the dominant unsaturated fatty acid in all mushrooms species in which Pleurotus cornucopiae contained as high as 5665.26 μg/g. Hygrocybe conica had a higher number of essential amino acids than all other mushroom species, while Pleurotus sp. and Trametes sp. had the least. The highest concentration of amino acids found were alanine, valine, methionine and glutamiC acid. Phenolic components were abundantly found in Schizophyllum commune (50.5 mg GAE/g of fresh sample) as compared to Lentinus edodes (24 mg GAE/g of fresh sample). Methanolic extracts of Scizophyllum commune and Hygrocybe conica showed comparable DPPH radical scavenging ability (96%) to the synthetic BHA at 1 mg/ml. BeSides, Hygrocybe conica is also a good chelator for ferrous ions with the chelating ability of 90.5% at 1 mg/ml, much higher than BHA at the same concentration. The antioxidant activity in Beta-carotene-linoleic acid bleaching assay were moderate for all mushrooms samples. These results demonstrate that the nutritional value of edible wild mushrooms compares favorably with cultivated mushrooms. Species with great nutritional properties would be the choice of selection for commercial cultivation and further exploration to abate micronutrient deficiency in local communities.