Effect of supercritical CO2 on myrosinase activity and glucosinolate degradation in canola

The effect of supercritical carbon dioxide (SC-CO2) extraction conditions (temperature, pressure, extraction time, and moisture content-of the samples) on the myrosinase activity and glucosinolate hydrolysis in flaked and whole canola seeds was studied. Combined effects of high temperature (75 degrees C), pressure (62.1 MPa), and moisture (similar to 20% w/w) were necessary to achieve 90% enzyme inactivation in canola flakes in 3 h. Similar extraction conditions resulted in only 44% enzyme inactivation in whole canola seeds. Significant glucosinolate degradation was observed after 5 h of extraction of low moisture content (8.5% w/w) whole canola seeds. Glucosinolate degradation in canola flakes was minimal at all moisture levels studied. Therefore, myrosinase inactivation prior to SC-CO2 extraction of canola flakes may not be necessary. However, the presence of enzyme activity in canola extracted at low moisture or temperature should be taken into account for further utilization of meal.