Ultrasound is recognized as a non-conventional processing technology for food preservation and quality improvement. Effects of thermal and ultrasound treatment on the inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) in bayberry juice were studied. Whether cooling with ice bath during ultrasound treatment was conducted to separate effects of heat and cavitation effects. In all processes, the inactivation kinetics of PPO and POD followed a first-order model (R² = 0.864–0.997).The D_T value during thermal inactivation varied from 151.99 to 6.23 min for PPO and the corresponding Z_T values and activation energy (E_a) were 13.16 °C and 166.77 kJ/mol, while those parameters of POD were 298.26–7.08 min, 14.25 °C and 153.49 kJ/mol, respectively. The ultrasound (US) inactivation rate constants (k) for PPO ranged from 0.0556 min^− 1 to 0.8878 min^− 1 with the corresponding D values of 41.44–2.59 min and Z_UI values of 312.50 W/cm². However, the k value of PPO during ultrasound with cooling (USC) decreased to 0.0412–0.3268 min^− 1, while the D and Z_UI values increased to 55.92–7.05 min and 432.90 W/cm², indicating that the heat brought out during ultrasound treatment significantly enhanced the inactivation kinetics of PPO. The inactivation rates of POD by US treatment were also higher than those by USC at the same ultrasound intensity and time. In addition, the kinetic parameters for POD by US and USC treatment were lower than those of PPO, inferring its more sonication resistant.

Industrial relevance

Ultrasound is a non-thermal food processing method for microorganism and enzyme inactivation, as well as quality maintenance. Attractive color is one of the most important quality attribute of bayberry products and strongly affects the consumer acceptance and preference. A key role in color degradation in berry fruit products is attributed to enzymatic browning of phenolic compounds which mainly related to PPO and POD. Therefore, the inactivation of PPO and POD is necessary for better color retention and shelf life increasing. This study would provide technical support for PPO and POD inactivation of ultrasound technique in bayberry juices processing.

中文翻译：

---

杨梅汁中热和超声处理过程中多酚氧化酶和过氧化物酶的失活动力学

超声波被公认为是用于食品保鲜和质量改善的非常规加工技术。研究了热处理和超声处理对杨梅汁中多酚氧化酶（PPO）和过氧化物酶（POD）失活动力学的影响。在超声处理过程中是否进行冰浴冷却以分离热效应和空化效应。在所有过程中，PPO和POD的失活动力学均遵循一阶模型（R ²  = 0.864–0.997）。PPO的热失活期间D _T值从151.99到6.23 min不等，相应的Z _T值和活化能（E _a）分别为13.16°C和166.77 kJ / mol，而POD的那些参数分别为298.26-7.08 min，14.25°C和153.49 kJ / mol。超声（US）的失活速率常数（K）为PPO范围为0.0556分钟^{- 1}到0.8878分钟^{- 1}与41.44-2.59分钟对应的d值和Z _UI 312.50瓦/厘米的值²。但是，超声冷却（USC）过程中PPO的k值降至0.0412–0.3268 min ^{− 1}，而D和Z _UI值分别升高至55.92–7.05 min和432.90 W / cm ^2。，表明在超声处理过程中散发的热量显着增强了PPO的失活动力学。在相同的超声强度和时间下，US处理对POD的灭活率也高于USC。此外，US和USC处理的POD动力学参数低于PPO的动力学参数，这表明其抗超声性能更高。

行业相关性

超声波是一种非热食品加工方法，用于微生物和酶的灭活以及质量保持。诱人的颜色是杨梅产品最重要的质量属性之一，并强烈影响消费者的接受度和偏好。浆果果实产品中颜色降解的关键作用归因于酚类化合物的酶促褐变，这主要与PPO和POD有关。因此，PPO和POD的失活对于更好的保色性和延长保质期是必要的。这项研究将为杨梅汁加工中超声技术的PPO和POD灭活提供技术支持。