大豆脂肪氧合酶超高压失活动力学研究

Ultra-high pressure inactivation kinetics of soybean lipoxygenase

为建立超高压技术工业化应用的基础,以豆浆为研究对象,研究了脂肪氧合酶的超高压失活动力学,试验压力为200～650 MPa,温度为5～60℃。结果表明：豆浆中脂肪氧合酶的超高压失活是不可逆的,并且符合一阶反应动力学。在某一恒定温度下（5℃≤T≤60℃）,脂肪氧合酶的失活速率常数k随着超高压处理压力的增加而增大。但是在某一恒定的压力下（550 MPa≤P≤650 MPa）,脂肪氧合酶的失活速率常数在10～20℃左右出现最小值,表明Arrhenius方程不能适用于整个温度区间。在中温区域（20℃≤T≤60℃）,温度对脂肪氧合酶失活速率常数的影响随着压力的增加而降低。而脂肪氧合酶失活速率常数对压力的敏感性大约在30℃时最大。

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℃.