Optimization of ultrasonic assisted process of extracting polyphenols from seed scales of Korean pine and their antioxidation.

We used the ultrasonic assisted method to extract the polyphenols from seed scales of Korean pine for the purpose of obtaining polyphenols with antioxidant activity efficiently. With polyphenols yield and DPPH radical scavenging rate as the indexes, we studied the effects of ultrasonic time, ultrasonic temperature, and ultrasonic power on the polyphenols yield and their antioxidant activity through single factor experiment. With polyphenols yield as the response value, and using the Box-Benhnken method, we designed the response analysis test with three factors and three levels. The results showed that the regression of mathematical model by ultrasonic assisted method for extracting polyphenols from seed scales of Korean pine is significant, and the optimal conditions are ultrasonic time 52 min, ultrasonic temperature 53 ℃, and ultrasonic power 300 W. Under these conditions, the polyphenols yield can reach 27.80 mg/g, comparable to that in water bath at the same temperature for 240 min, but extraction time is 2 hours less. IC50 value of pine polyphenols is 20.72 μg/mL for DPPH radical scavenging, 20.69 μg/mL for hydroxyl free radical clearance, and 259.71 μg/mL in the ultra oxygen anion clearance. The pine polyphenols have high total reducing power.