The effect of ultrasound treatments (40 kHz; 40, 50, or 60°C; 5 or 10 min) and thermal treatment (90°C; 30 s) on the stability parameters of orange-carrot juice were evaluated. Microscopic structure, particle size distribution and turbidity were analyzed on the first day. Sedimentation and cloudiness were evaluated over 22 days of storage at 7 and 25°C. Changes in microstructure and disruption of the cell wall were evidenced after treatment at 60°C/10 min. The particle size distribution was heterogeneous with an increase of small particles after ultrasonication. Ultrasonicated and thermal treated samples did not show any differences in turbidity. Cloudiness increased after sonication and decreased over the storage in all samples. Sedimentation process at 7°C was homogeneous among samples while it was delayed in samples treated with ultrasounds at 60°C for 10 min. Ultrasound processing improved the quality of juices and can be proposed as a potential novel processing technique for blended vegetable-fruit juices.

Ultrasound combined with high temperatures (thermosonication) is an alternative to thermal treatments applied for juice preservation purposes. Blend juices, such as orange-carrot juice, are an interesting option for consumers due to their diversity of unique flavors. The main aim of the present study is to investigate thermosonication’s impact on the overall quality of an orange-carrot juice blend over 22-day storage at 7 °C, in comparison to thermal treatment. Sensory acceptance was assessed on the first storage day. The juice blend was prepared based on using 700 mL of orange juice and 300 g of carrot. The effect of ultrasound treatment at 40, 50, and 60 °C for 5 and 10 min, as well as of thermal treatment at 90 °C for 30 s, on the physicochemical, nutritional, and microbiological quality of the investigated orange-carrot juice blend was tested. Both the ultrasound and the thermal treatment could maintain pH, °Brix, total titratable acidity, total carotenoid content, total phenolic compounds, and the antioxidant capacity of untreated juice samples. All ultrasound treatments improved samples’ brightness and hue value, and made the juice brighter and redder. Only ultrasound treatments at 50 °C/10 min and at 60 °C/10 min have significantly reduced total coliform counts at 35 °C. Thus, they were selected along with untreated juice for sensory analysis, whereas thermal treatment was used for comparison purposes. Thermosonication at 60 °C for 10 min recorded the lowest scores for juice flavor, taste, overall acceptance, and purchase intention. Thermal treatment and ultrasound at 60 °C for 5 min recorded similar scores. Minimal variations in quality parameters were observed over 22-day storage in all treatments. Thermosonication at 60 °C for 5 min has improved samples’ microbiological safety and resulted in good sensorial acceptance. Although thermosonication has the potential to be used in orange-carrot juice processing, further investigations are necessary to enhance its microbial effect on this product.