超高压处理对鲜橙汁中果胶酶及过氧化物酶活性的影响

Effect of Ultra High Pressure Treatment on Pectin Methylestrase and Perdoxidase in Orange Juice

为推进国内非冷冻浓缩橙汁加工业的发展,对新型超高压杀菌技术对橙汁中酶钝化的效果进行研究,采用200～600MPa超高静压处理鲜榨橙汁,使用紫外分光光度法、滴定法分别测定鲜橙汁中过氧化物酶(POD)和果胶酶(PME)的活性,进行两种酶在常温下超高压钝化酶一级动力学拟合研究。结果表明:在常温条件下200MPa处理10min使两种酶轻微激活,在300～600MPa条件下,随压力和处理时间的增大,两种酶钝化反应明显,且符合一级动力学模型,且果胶酶对压力钝化更加敏感。

In order to promote the industrialization of not from concentrated orange juice（NFCOJ）,ultra-high pressure（UHP） sterilization was used for the inactivation of pectin methylesterase（PME） and peroxidase（POD） in orange juice.UHP treatment for fresh juice was performed at ambient temperature and pressures ranging from 200 to 600 MPa.The remaining activity of PME（pectin methylesterase） and POD（peroxide dismutase） in processed juice was measured by titration and UV-visible spectroscopy,respectively.The results showed both enzymes were slightly activated after 10-min treatment at 200 MPa.An obvious inactivation of PME and POD were observed when the pressure was higher than 300 MPa up to 600 MPa and the treatment time was prolonged,and the inactivation in the pressure range from 300 to 600 MPa was fitted well to the first-order kinetic model.Moreover,PME was more sensitive to pressure than POD.