Air-borne ultrasonic application in the drying of grape skin: Kinetic and quality considerations

Both temperature and ultrasound application had a significant (p < 0.05) influence on the drying kinetics, which were satisfactorily described by both the Peleg and diffusion models. In addition, both factors significantly (p < 0.05) influenced the total phenolic concentration and antioxidant capacity of the extracts. Ultrasound application reduced the antioxidant potential, probably due to oxidase activation and cell degradation. Bioactive potential, on the other hand, was increased as a consequence of high-temperature drying, leading in particular to a greater release of malvidin 3-O-β-D-galactoside.