Optimization of microwave-assisted extraction for polyphenols and antioxidants from Cordyceps militaris base

Cordyceps militaris is a valuable fungus. However, most research considers fruiting bodies while the solid growth medium is ignored. This study investigated microwave-assisted extraction (MAE) parameters for improving the recovery of phenolic compounds, as chemical markers, and associated antioxidant activity, as functional response, from the medium. To support MAE optimization, preliminary factors affecting efficiency were first evaluated, including particle size determination and establishing magnetic stirring conditions. Powders <0.25 mm produced higher total phenolic content (3.51 ± 0.36 mg GAE/g dry weight), total flavonoid content (6.03 ± 1.23 mg QE/100 g), and antioxidant capacity (9.9 ± 1.38 µmol TE/g). Combinations of temperature (50-70 °C) and time (5-20 min) with stirring were examined using principal component analysis, showing optimal conditions at 60 °C for 15 min. Finally, MAE factors were optimized using a factorial design. ANOVA and response surface methods showed that 560 W for 8 min produced the highest extraction values.