[Studies on ultrasonic wave extracting method determining konjac glucomannanin konjac refined powder].

ABSTRACT

OBJECTIVE: To investigate the effect of ultrasonic wave on extracting Konjac Glucomannan(KGM) in Konjac refined powder. METHOD: Free reduced sugar in Konjac refined powder was removed and Konjac refined powder in the aqueous solution was processed by ultrasonic wave and KGM content was measured by spectrophotometry. RESULT: KGM content in the Konjac refined powder aqueous solution by ultrasonic process at fixed 40 kHz, 100 W, 30-45 min was equal to that by routine method at 4 h; whereas, by 1 h of ultrasonic process, KGM content was significantly enhanced than that by 4 h of routine method(P < 0.01), enhancement rate was 6.5%. Linearity of standard glucose was good (r = 0.9996) in range of 0.2-1.6 mg. The average recovery was 97.8%, RSD of repeatability was 1.27%. CONCLUSION: Ultrasonic extraction in aqueous solution is a reliable and rapid method that can enhance extraction efficiency of KGM in Konjac refined powder.