Beyond Growth: Substrate-Dependent Variations in the Proximate, Phytochemical and Mineral Composition of White Oyster (Pleurotus ostreatus)

This study assessed the impact of three readily available substrate materials, namely sawdust, maize cob leaves and banana leaves, on the constituents of Pleurotus ostreatus. The mushroom was cultivated under the same conditions on the substrates independently, harvested, and analysed for proximate, mineral, and phytochemicals in line with standard protocols. Significant differences (p < 0.05) were noted in crude protein, crude fat, crude fibre, and ash contents. The mushroom grown on sawdust had the highest protein content, while those cultivated on maize cob leaves recorded higher levels of crude protein, crude fat, crude fibre, and ash. Some phytochemicals (oxalates, phytates, phenols, and saponins), and all the mineral elements analysed, were significantly influenced by the substrate type. Banana leaves supported Mn and K accumulation, while maize cob leaves favoured Fe, Zn, and Mg in the grown mushrooms. These results show that the choice of substrate for the cultivation of mushrooms can affect their compositional characteristics. No single substrate wholly produced mushrooms with the highest levels of all the measured constituents, but each substrate was linked to particular nutritional and mineral contents. This study highlights the potential of readily available agricultural residues as substrates for cultivating P. ostreatus with differing nutritional profiles and provides useful information for selecting substrates according to desired mushroom quality