The use of ultrasound treatment influenced the carotenoid content in carrot tissue (Fig. 5). Raw carrot was characterized by total carotenoids content equal to 7.66 mg/100 g of fresh weight. This amount was expressed in percent as 100%, in order to simplify the presentation and interpretation of the total carotenoids content in research samples. After 20 min of ultrasound treatment at a frequency of 21 kHz significant increase (12.5%) in carotenoid content was observed. In the case of samples treated at a frequency of 35 kHz, carotenoid content increased significantly after 10, 20 and 30 min treatment by 42.3%, 49.9% and 41.1%, respectively. A similar changes were observed by Abid et al. [48] during the sonication at 25 kHz frequency of fresh apple juice, where the carotenoids content increased up to 12% and 27% after 30 and 60 min of ultrasound treatment, respectively.