Abstract:

Fruit bodies of Pholiota nameko were used as the raw material to extract Pholiota nameko polysaccharide (PNP) by ultrasonic-assisted extraction. Optimal PNP extraction process was investigated using orthogonal array design. To evaluate the antioxidant activity of PNP, total reducing power and scavenging capacity against superoxide anion or hydroxyl radicals were assayed using in vitro simulated chemical systems. Results showed that the optimum PNP extraction conditions were as follows: ultrasonic power 700 W, ultrasonic treatment time 16 min, extraction temperature 75 ℃, and solid/liquid ratio 1:30. Under the optimum conditions, PNP yield reached up to 9.17%. PNP showed strong in vitro reducing power and free radical-scavenging capacity. Thus, PNP has good potential as a natural antioxidant used in food or medicine industries.

Key words: Pholiota nameko, polysaccharide, ultrasonic, orthogonal array design, antioxidant activity