Influence of conventional blanching and sonication on the quality parameters of black carrot (Daucus carota L.) juice: a comparative analysis

Summary Black carrot is a peculiar variety of carrot that is known for its deep purple‐black colour and its high levels of antioxidants. Black carrots were subjected to five different treatments, namely, hot water blanching, acidified water blanching, sonication and sonication combined with hot water blanching and acidified blanching. The untreated juice was taken as control. The effect of both conventional (blanching) and non‐conventional (sonication) methods on the quality attributes of black carrot juice was evaluated. The application of blanching treatments resulted in significant ( P < 0.05) reduction in peroxidase activity, however, sonication alone was comparatively ineffective. The sonication exhibited a significant ( P < 0.05) increase in minerals, phytochemicals and antioxidant activities. Conversely, conventional blanching treatments reduced their content. All treated samples exhibited significant ( P < 0.05) decrease in microbial count as compared to control. However, the decline was more pronounced in juices subjected to simultaneous acidified water blanching and ultrasound treatment. The findings demonstrate that combining ultrasound treatment with blanching offers advantages in improving the phytochemical constituents, microbial safety, and overall quality of black carrot juice.