Inactivation of lipoxygenase in whole soy flour suspension by ultrasonic cavitation

Abstract

Abstract Use of ultrasound for lipoxygenase inactivation in whole soy flour suspension was studied. Inactivation of the enzyme was influenced by the time of exposure, pH, and the amplitude of ultrasound. Exposure to cavitating 20 kHz ultrasound for 3 h at pH > 5.0 had no effect on the activity of the enzyme. However, under similar conditions, the activity decreasd by 70‐85% when pH was lowered to 5.0 and 4.0, respectively. Lipoxygenase activity also decreased with increase in frequency of the ultrasound waves when pH was ≥5.0; above pH 5.0, increase in frequency did not affect the enzyme activity after an exposure of 1 h.