Effects of ultrasound treatment in purple cactus pear (Opuntia ficus-indica) juice

► This is the first report on the effects of sonication on purple cactus pear juice. ► Sonication was effective in reducing the microbial load of the juice. ► Sonication of juice resulted in the enhancement of antioxidant compounds. ► Results will be useful for preserving quality and for overcoming safety issues. ► Results obtained will be valuable for implementation of sonication. Cactus pear (Opuntia ficus-indica) fruit is a berry with a tasty pulp full of seeds that constitutes about 10–15% of the edible pulp. In Mexico, cactus pear is mainly consumed fresh, but also has the potential to be processed in other products such as juice. The objective of this study was to evaluate the effect of different ultrasound conditions at amplitude levels ranging (40% and 60% for 10, 15, 25min; 80% for 3, 5, 8, 10, 15 and 25min) on the characteristics of purple cactus pear juice. The evaluated parameters were related with the quality (stability, °Brix, pH), microbial growth, total phenolic compounds, ascorbic acid and antioxidant activity (ABTS, DPPH and % chelating activity) of purple cactus pear juices. The ultrasound treatment for time period of 15 and 25min significantly reduced the microbial count in 15 and 25min, without affecting the juice quality and its antioxidant properties. Juice treated at 80% of amplitude level showed an increased of antioxidant compounds. Our results demonstrated that sonication is a suitable technique for cactus pear processing. This technology allows the achievement of juice safety and quality standards without compromising the retention of antioxidant compounds.