Ultrasound-Microwave Co-Extraction and Antioxidant Activity Analysis of Polysaccharides from Morchella Esculenta L. Mycelium Obtained through Submerged Fermentation

Morchella esculenta L. is a rare and the most valuable edible mushrooms. The polysaccharides of M. esculenta L. boast high nutrition and health values. This paper describes microwave extraction of the polysaccharides of M. esculenta L. by ultrasonic microwave. The optimal extraction conditions, optimized by single factor experiments and response surface method, were determined as follows: the ultrasonic power is 250 W, the microwave power is 220 W, and the extraction time is 7 min with a yield of polysaccharides at 4.425%. The crude polysaccharides of M. esculenta L. at 4 mg/mL exhibited hydroxyl radical, 2-Diphenyl-1-picrylhydrazyl radical and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging rates at 76.70%, 60.73%, and 80.87%, respectively. Its Fe2+ chelating rates increased from 45.63% to 82.50%, as the polysaccharide concentration increased from 0.5 to 4.0 mg/mL.