介质特性对超声波钝化芒果多酚氧化酶和过氧化物酶的影响

Influence of Medium Properties on the Inactivation Effect of Polyphenol Oxidase and Peroxidase of Mango by Ultrasound

基于超声波对芒果汁中多酚氧化酶(PPO)和过氧化物酶(POD)钝化效果显著低于对芒果粗酶液钝化效果的现象,通过调整粗酶液中糖分、蛋白质含量、介质黏度和pH值,探讨影响超声波钝酶效果的可能因素。采用的超声波处理条件为45℃,799.31 W/cm2,15 min。结果表明,超声波对糖度为5.0~20 Brix的粗酶液中PPO和POD钝化率比糖度为4.4 Brix的粗酶液分别降低了20.67%~29.36%和40.34%~46.22%(P<0.05);超声波对蛋白质添加量为0.5%~2.5%粗酶液中PPO和POD的钝化率比未添加组分别降低了24.55%~30.9%和42.36%~47.19%(P<0.05)。采用添加不同增稠剂来调整粗酶液的黏度,结果发现超声波对黏度为17.6~27.1 mPa·s的粗酶液中PPO和POD的钝化率比未调整组(黏度15.2 mPa·s)分别降低了27%和30%(P<0.05),而不同增稠剂对超声波钝酶效果的影响差异不显著(P>0.05)。通过添加柠檬酸来调整粗酶液的pH,发现超声波对pH 4.0和pH 5.0的粗酶液中PPO和POD的钝化率比未调整组(pH 5.2)降低了22.73%~27.19%和34.58%~41.32%(P<0.05)。上述结果表明食品组分、pH和介质黏度显著影响超声波的钝酶效果。

Based on the phenomenon that the passivation rate of ultrasonic wave on polyphenol oxidase and peroxidase in mango juice was significantly lower than that on mango crude enzyme solution,the possible factors affecting the passivation effect of ultrasonic wave were discussed by adjusting the content of food components and medium viscosity in the crude enzyme solution.The treatment conditions were 45℃,799.31 W/cm2 and 15 min.It was found that the passivation rates of PPO and POD by ultrasound in crude enzyme solution with a sugar content of 5.0-20 Brix were decreased by 20.67%-29.36%and 40.34%-46.22%(P<0.05)respectively,compared with the original crude enzyme solution with a sugar content of 4.4 Brix.Similarly,the passivation rates of PPO and POD by ultrasound in crude enzyme solution with an additional amount of 0.5%-2.5%were decreased by 24.55%-30.9%and 42.36%-47.19%(P<0.05),respectively,compared with the original crude enzyme solution.The viscosity of the crude enzyme solution was adjusted by adding different thickeners,it was found that the passivation rates of PPO and POD by ultrasound in crude enzyme solution with the viscosity of 17.6-27.1 mPa·s were decreased by 27%and 30%(P<0.05),respectively,compared with the unadjusted group with viscosity of 15.2 mPa·s,but the ultrasonic inactivation effect among different thickeners was similar(P>0.05).The pH of the crude enzyme solution was adjusted by adding citric acid,it was found that the passivation rates of PPO and POD by ultrasound in crude enzyme solution with the pH of 4 and 5 were decreased by 22.73%-27.19%and 34.58%-41.32%(P<0.05),respectively,compared with the unadjusted group with pH of 5.2.The results indicated that food components,pH and medium viscosity could affect the enzymes inactivation ratio of ultrasound.