Ultra-high pressure inactivation kinetics of soybean lipoxygenase

In order to establish the foundation for the industrial application of high pressure technology, the ultra-high pressure inactivation kinetics of lipoxygenase in soy milk were studied in the pressure range of 200～650 MPa with temperature varying from 5℃ to 60℃. The results suggest that isobaric-isothermal inactivation of lipoxygenase is irreversible and follows a first-order reaction. The lipoxygenase inactivation rate constants increases with the pressure increasing at a constant temperature(5℃≤T≤60℃). Whereas at a constant high pressure(550 MPa≤P≤650 MPa), lipoxygenase exhibits the greatest stability around 10～20℃, indicating the Arrhenius equation not to be valid over the whole temperature range. The effects of the temperature on the lipoxygenase inactivation rate constants in mild temperature area(20℃≤T≤60℃) decrease with pressure increasing, while the highest sensitivity of the lipoxygenase inactivation rate constants to pressure is at about 30℃.