Optimization of the extraction of bioactive compounds from chaga mushroom (Inonotus obliquus) by the response surface methodology

Abstract

This study determined the optimum extraction conditions based on five response variables (yield, total phenolics, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavanging activity, oxygen radical absorbance capacity (ORAC), and β-1,3-glucan content) in chaga mushroom (Inonotus obliquus) using the response surface methodology, where three independent variables (ethanol concentration, extraction temperature, and extraction time) were optimized using a central composite design. The optimum ethanol concentration, extraction temperature, and extraction time were 50% (w/w), 88.7°C, and 14.5 h; 9.2%, 92.7°C, and 14.5 h; 50.8%, 92.7°C, and 14.5 h; 9.2%, 92.7°C, and 1.5 h; and 90.8%, 92.7°C, and 1.5 h for yield, total phenolics, ABTS, ORAC, and β-1,3-glucan content, respectively. The predicted values of the response variables were compared with those of the extracts under the optimal extraction conditions to verify the models. The optimum extraction condition for the five response variables was predicted to be 81.4% ethanol at 92.7°C for 14.5 h.