The aim of this study was to investigate whether ultrasound (US) assistance during the osmotic pretreatment
of sour cherries has any influence on quality and changes in the levels of bioactive compounds
present in dried product during storage using an accelerated shelf-life test. Sour cherries of ‘Nefris’ variety
were pitted in a frozen state and subjected to osmotic dehydration in a water bath fitted with
ultrasound transducers (25 kHz, 0.4 W/cm2) and a shaking plate (30 rpm) in sucrose solution (60 Bx,
fruit to syrup ratio 1:4, 40 C) and then convectively dried (60 C, 9 h, 2.5 m/s). The osmotic dehydration
lasted 120 min with (60US) and without US (0US) treatment. The application of US resulted in the
enhancement of mass transfer after osmotic dehydration (higher dry matter content and lower water
activity in dried 60US sample in comparison to 0US). Storage caused the deterioration of anthocyanin
content and after 8 weeks of storage significant differences between samples became visible. Samples
treated with US application had a lower antiradical capacity than those untreated. It can be anticipated
that ultrasound application had a negative influence on anthocyanin content and may speed up the loss
of antioxidant potential.