European Journal of Nutrition & Food Safety

Efficient conversion of agricultural residues and fruit-processing wastes into edible biomass requires suitable mushroom cultivation substrates. The investigation evaluated the influence of lignocellulosic substrate and fruit waste combinations on the growth, yield, fruiting-body characteristics and nutritional composition of Pleurotus florida. Eight treatments comprising paddy straw and finger millet straw combined with orange peel or pineapple peel at 2:1 and 3:1 ratios were evaluated in a completely randomised design with three replications. Growth, yield, biological efficiency, fruiting-body characteristics, proximate composition, antioxidant activity and total phenolic content were assessed, and gas chromatography–mass spectrometry (GC–MS) analysis was performed on mushrooms harvested from the selected treatment. Among the treatments, mushrooms harvested from finger millet straw + pineapple peel (2:1) (T7) recorded the shortest spawn run (17.80 days), earliest pinhead initiation (20.10 days) and earliest first harvest (24.10 days), along with the highest total yield (814.4 g kg⁻¹ dry substrate) and biological efficiency (81.44%). Mushrooms harvested from finger millet straw + pineapple peel (2:1) (T7) also recorded the highest number of fruiting bodies (127.20) and the highest carbohydrate (55.30%), protein (25.60%), fat (2.05%), ash (8.12%) and total sugar (3.97%) contents, together with the lowest moisture content (89.77%). In contrast, mushrooms grown on finger millet straw + orange peel (2:1) (T5) exhibited the highest antioxidant activity (78.40%) and total phenolic content (24.10 mg gallic acid equivalents g⁻¹ dry weight). GC–MS profiling of mushrooms harvested from finger millet straw + pineapple peel (2:1) (T7) identified seven major compounds, with ergosterol as the predominant detected compound. These findings indicate that finger millet straw combined with pineapple peel at a 2:1 ratio was the most promising substrate formulation for improving the productivity and proximate composition of P. florida, whereas finger millet straw combined with orange peel at the same ratio was more favourable for antioxidant activity and total phenolic content. The study highlights the potential of utilising agricultural residues and fruit-processing wastes as alternative cultivation substrates for sustainable oyster mushroom production and biomass valorisation.