Optimization of ergosterol extraction from Pleurotus mushrooms using response surface methodology

In this study, heat-assisted extraction (HAE) was used to maximize ergosterol extraction from Pleurotus ostreatus (PO) and Pleurotus eryngii (PE) using response surface methodology (RSM). Different temperature (T) and time (t) conditions were applied to understand their influence on the extraction yield (Y₁), ergosterol purity in the extracted material (mg g^-1 R, Y₂) and ergosterol content in the two Pleurotus species (mg per 100 g dw, Y₃). A circumscribed central composite design was used to evaluate the interactive effects of extraction variables and the optimal conditions were determined using second-order polynomial mathematical models to describe the responses obtained. In all cases, the predicted responses showed satisfactory fitting between the predicted and experimental values (R² values >0.8). The global optimum conditions predicted by the models were for PO at T = 54.3 °C and t = 150 min (yielded 7.25%, 33.32 mg E per g R and 244.25 mg E per 100 g dw), while for PE at T = 61.8 °C and t = 150 min (yielded 8.02%, 43.63 mg E per g R and 360.58 mg E per 100 g dw). The obtained results from the two Pleurotus mushroom species using HAE show the possibilities of using them as a production source of enriched extracts in ergosterol.