Abstract
The effect of microwave-assisted finish drying following osmotic dehydration with the application of ultrasound was investigated. Qualitative characteristics of dried black cherries (polymeric anthocyanin, loss of anthocyanin into osmotic solution, texture) were determined. Osmotic dehydration was done ...
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The effect of microwave-assisted finish drying following osmotic dehydration with the application of ultrasound was investigated. Qualitative characteristics of dried black cherries (polymeric anthocyanin, loss of anthocyanin into osmotic solution, texture) were determined. Osmotic dehydration was done in osmotic solution (sucrose-water) with concentrations of 40%, 50%, and 60% sucrose. Osmotic dehydration was determined at 40, 50 and 60 °C. The influence of ultrasonic frequency at 65 and 130 KHz was also studied. To increase the permeability of skin of the black cherries, they were dipped in NaOH (0.5 mol) for 2 min. Microwave drying was done at 100 W, 200 W and 300 W to complete the drying process. Response surface methodology was used to optimize the osmotic-ultrasound-microwave drying conditions of the black cherry to achieve minimum loss of anthocyanin into the osmotic solution and polymeric anthocyanin. Experiments used a central composite rotatable design. The results showed that drying condition had a significant effect on anthocyanin loss, polymeric anthocyanin, and texture after dehydration. The optimal conditions for minimum anthocyanin loss were a temperature of 40°C, 40% concentration and ultrasonic frequency of 40.7 kHz. The optimal conditions for minimum polymeric anthocyanin were a temperature of 44.44°C, 60% concentration, 300 W of power and no ultrasonic frequency.
