Influence of physical conditions on soybean isoflavone antioxidant properties

Ultrasonic method was used to extract soybean isoflavone, and antiphase flow injection chemilum-inescence was used to measure light intensity(I) that is a indicatrix of influence of several physical factors including state(solid, liquid), storage temperature, storage time and the concentration of the soy isoflavone liquid on soy isoflavone antioxidative activity. The results showed that in the determination time(30 d), solid affected by temperature was not obvious, while liquid was obvious, with temperature increasing the activity decreased quickly; the appropriate concentration for the preservation was 10 μg·mL-1, and the appropriate temperature was -20℃, under this condition the liquid would be conserved for a comparatively long time(≤24 d), but would not suitable for long preservation.