Evaluation of Cashew Pulp and Shell, Kola, Cocoa and Coffee Husk as Substrates for the Cultivation of Pleurotus ostreatus

Aims: Coffee, cocoa, kola and cashew shells and cashew pulp, all agricultural waste were evaluated as potential raw materials for cultivating Pleurotus ostreatus and to determine the influence of substrate on mushroom nutritional quality.

Methodology: Composted substrates were bagged, inoculated with spawn and cropped. Treatments were arranged in a Completely Randomised Design in the cropping house. Substrate colonization, yield and nutritional quality of mushroom carried out using various biochemical tests.

Results: Mushroom grown on cashew pulp had significantly lower levels of total polyphenols than the other five substrates suggesting that bioaccumulation of phenolics by the fungus was not dependent on the levels originally present in the substrate. Carbohydrates, one of the major constituents of mushroom, ranged from 11% in cocoa to 20.6% in cashew pulp. In terms of soluble sugars, cashew pulp mushroom had significantly (P < .05) higher levels of soluble sugars than the others. Heavy metal levels were all low and within the recommended for food products. Low crude fat content characterized the samples, significantly influenced by substrate and ranged from 0.95% (Kola husk) to 2.83% (cocoa pod husk) in dry mushrooms. Significant differences observed in the dry matter content of the mushroom grown on the six substrates, with values ranging from 8.01 to 13.96%. Mushroom from cashew shell and coffee husk had the lowest dry matter among the treatments.

Conclusion: Kola husk, cocoa pod husk, cashew pulp and cashew shell as available agricultural wastes produced in the country have high potential for utilization as substrates for the cultivation of P. ostreatus mushroom with good nutritional value. Some nutrient compositions were however influenced by the substrate used. All substrates supported P. ostreatus growth fruiting, however coffee husk did produce lower yields in terms of biological efficiency.