为探究超声波处理对西瓜汁品质的影响，以西瓜为原料，经榨汁后用100、200、300 W超声波分别处理10、20和30 min，并考察了超声处理后西瓜汁品质的变化情况。结果表明，超声波处理的功率与时间对西瓜汁品质有显著影响，随着超声波作用强度的增加，西瓜汁PPO和POD的活性逐渐降低，当以300 W超声功率处理西瓜汁30 min后，PPO和POD的活性分别降低了55%和40%。超声波处理并未改变西瓜汁的酸甜度，但西瓜汁的电导率会随超声波作用强度的增加而增加。超声处理后的西瓜汁相比于空白组西瓜汁的ΔΕ均小于0.8，与热处理组对比，超声波处理的西瓜汁可较好地保留原有的色泽。当超声波处理时间大于10 min后，西瓜汁的黏度将显著升高，当用200 W超声处理30 min后，西瓜汁黏度提升近1倍。与空白对照组相比，超声波处理的西瓜汁L-抗坏血酸含量稍有降低，降低值仅为热处理的 2.7%～23.98%，而总酚含量变化不明显，超声波处理可较好地保留西瓜汁的营养成分，保持西瓜汁的商品价值。

In order to investigate the effect of ultrasonic treatment on the quality of watermelon juice, the juice was treated with 100 W, 200 W and 300 W ultrasonic waves for 10 min, 20 min and 30 min, respectively. The quality of watermelon juice after ultrasonic treatment was studied. The results showed that the power and time of ultrasonic treatment had significant effects on the quality of watermelon juice, the activity of PPO and POD in watermelon juice gradually decreased with the increase of ultrasonic. When watermelon juice was treated with 300 W ultrasonic power for 30 min, the activities of PPO and POD were reduced by 55% and 40%, respectively. Sonication did not change the acidity of watermelon juice; however, the conductivity of watermelon juice increased with the increase of the intensity of ultrasonic effect. ΔE of watermelon juice after ultrasonic treatment as well as the control group were all lower than 0.8 for watermelon, compared with the heat treatment group, ultrasonic watermelon juice retained the original color better. The viscosity of watermelon juice increased significantly when the ultrasonic treatment time is longer than 10 min, and watermelon juice viscosity nearly doubled after 200 W ultrasonic treatment for 30 min. Compared with the control group, ultrasonic treatment of watermelon juice L-ascorbic acid content decreased slightly, the value of reduction is only 2.7%-23.98% of heat treatment, the total phenolic content was not obvious. Ultrasound treatment retained the nutritional and commercial value of watermelon juice.