Influence of ultrasound on the qualitative properties of carrot purée
Ultrasound is one of the emerging technologies developed to minimize processing, maximize quality, and ensure food safety. In this context, the objective of a recent study, carried out by a group of Polish researchers (Janiszewska-Turak et al., 2024), was to assess the effects of ultrasonic frequencies between 21 and 35 kHz on the qualitative properties of carrot purée samples at different concentrations (9, 12 and 21° Brix).
The product viscosity indicates a shear thinning behaviour, typical of non-Newtonian fluids. Furthermore, it has been observed that the activation energy necessary for heat transfer and enzyme inactivation decreases with higher ultrasonic power intensity; this is particularly interesting as a lower energy demand results in a faster transformation process, that can take place even at lower temperatures.
A significant effect of this may be the observed change in the purée colour after ultrasonic treatment: The increase in frequency from 21 to 35 kHz caused an increase in redness and yellowness and a decrease in lightness, independently of the concentration. In conclusion, the authors argue that the information acquired with this study, although requiring further study, can be useful to the industry for the development of new energy-efficient transformation processes.
