INACTIVATION OF LIPOXYGENASE IN WHOLE SOY FLOUR SUSPENSION BY ULTRASONIC CAVITATION

Use of ultrasound for lipoxygenase inactivation in whole soy flour sus pension was studied. Inactivation of the enzyme was influenced by the time of exposure, pH, and the amplitude of ultrasound. Exposure to cav itating 20 kHz ultrasound for 3 h at pH > 5.0 had no effect on the act ivity of the enzyme. However, under similar conditions, the activity d ecreasd by 70-85% when pH was lowered to 5.0 and 4.0, respectively. Li poxygenase activity also decreased with increase in frequency of the u ltrasound waves when pH was less than or equal to 5.0; above pH 5.0, i ncrease in frequency did not affect the enzyme activity after an expos ure of 1 h.