Compositional studies on edible tropical species of mushrooms

The nutritive potential of some edible tropical species of mushrooms such as Termitomyces robustus, Termitomyces microcarpus, Psathyrella antroumbonata, Lentinus subnudus, Auricularia auricula, Calvatia cyathiformis, ‘Peperu’ and Schzophyllum commune were evaluated with respect to their proximate composition, energy values, mineral (trace and major) content, phytin, phytin-phosphorus and oxalate constituents. On average they contained 22.1 g/100g DM crude protein with a range of 8.9 g/100 g DM in A. auricula to 33.8 g/100 g DM in T. robustus. The crude fibre ranged from 2.1 to 8.0 g/100 g DM while the ash ranged from 2.1 to 13.9 g/100g DM. All the varieties had low levels of ether extract ranging from 0.1 g/100 g DM in C. cyathiformis to 0.2 g/100 g DM in L. subnudus. The gross energy ranged from 2.5 kcal/g in P. atroumbonata to 3.02 kcal/g in T. robustus. Potassium was the most abundant mineral while magnesium was the least. There were high interspecies differences in the components analysed as indicated by the high coefficients of variation (CV). Phytic acid content varied from 160 mg/100 g in T. robustus to 360 mg/100 g in C. cyathiformis with a CV of 28.4% while oxalate content varied from 80 mg/100 g in T. robustus to 220 mg/100 g in A. auricula with a CV of 3.8%. Based on the results, measures were suggested for harnessing mushroom nutritional potentials.