Effect of locally available substrates on the mineral and bioactive compounds of oyster mushrooms (Pleurotus ostreatus).

Abstract

Oyster mushrooms are recognized for its potential to address malnutrition and other health issues due to its rich nutritional content. They are typically cultivated above the ground on various substrates. While different substrates are known to be effective for oyster mushroom production, their impact on the mushroom's nutritive content remains unclear. To fill this knowledge gap, this study investigated the effects of three local substrates on the mineral and bioactive compound content of oyster mushrooms. The research design was a Completely Randomized Design (CRD) and carried out under controlled conditions (Temp of 25-28 C and RH of 60-70%). The treatments were millet husk, cotton seed husk, and coffee husk being used as substrates. The results showed that the nutrient composition of each of the substrates was; Coffee Seed husks (N-1.074%, C-6.234%, C: N-5.82, pH-5.2); Cotton Seed husk (N-0.422%, C13.953%, C: N-33.1, pH-7.01); Millet husks (N-0.792%, C 2.278%, C: N-2.88, pH-7.461). Magnesium content was higher in oyster mushroom produced using cotton seed husks with 23.6mg/100g, millet and coffee husk substrates produced oyster mushroom with the same amount of mg. Cotton husks produced mushroom with higher content of zinc (7.840mg/100g), followed by coffee husk with 6.624 mg/100g and least was Millet husk with (3.838mg/100g.); the content of Cd and pb were below detectable level in oyster mushroom produced using the different substrates. The coffee husks substrates showed a significantly high phenolic and flavonoid contents compared to both millet and cotton seed husk. Additionally, Vitamin C content was significantly higher in both Coffee and millet husks, 4.699g/kgDW and 5.191g/kgDW respectively. In conclusion, the study suggests that coffee husk is the most effective substrate for producing oyster mushrooms with higher bioactive compound levels, while cotton seed husk is more suitable for maximizing mineral contents. The potential synergies of combining coffee husks and cotton seed husks for oyster mushroom production should be recommended so as to achieve higher quantities of both bioactive compounds and mineral contents in mushrooms.