Optimization of Ergothioneine Extraction Process From <i>Pleurotus citrinopileatus</i> and Its Antioxidant Activity

ABSTRACT Ergothioneine (EGT), a natural antioxidant extracted from edible fungi, has broad applications in pharmaceutical and cosmetic sectors; however, research on it in the food industry remains relatively limited. This study aims to enhance the extraction efficiency of EGT from Pleurotus citrinopileatus through an ultrasound‐microwave‐assisted extraction (UMAE) method. Through comparative analysis of EGT content across various edible mushroom species and Chinese P. citrinopileatus from different regions, P. citrinopileatus originating from Yunnan Province, China, was selected as experimental material. Operational parameters, including microwave power, ultrasonic power, and temperature, were optimized using Response Surface Methodology to evaluate the significant interactions between these process variables and significantly improve the extraction yield. Under the optimized conditions of 80°C, 505 W microwave power, 508 W ultrasonic power, a liquid‐to‐solid ratio of 61:1 (mL/g), and a 15‐min period, the EGT yield reached 3.75 mg/g DW. The robust methodology was validated using high‐performance liquid chromatography and liquid chromatography‐mass spectrometry. Antioxidant assays demonstrated that the extract exhibited potent scavenging activity against hydroxyl, DPPH (2,2‐diphenyl−1‐picrylhydrazyl), and ABTS [2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid)] radicals, achieving maximum scavenging rates of 64.69%, 95.76%, and 95.89%, respectively. Pearson correlation analysis revealed strong positive correlations ( R 2 = 0.823–0.966) between the extract and pure EGT, suggesting EGT as a key contributor to the antioxidant activity of the extract, while non‐EGT components may also play complementary roles.