Ultrasound as pretreatment to convective drying of Andean blackberry (Rubus glaucus Benth)
Autor
Romero J., Carlos A.
Yépez V., Byron D.
Institución
Resumen
In this study, we evaluated the use of ultrasound as a pretreatment for convective drying of Andean
blackberry (Rubus glaucus Benth). For this, a Box-Behnken experimental design was used to study the
effect of ultrasound vibration amplitude (0–90 lm), time of sonication (10–30 min) and air temperature
(40–60 C) on the retention of antioxidant compounds and on the kinetics of convective drying. The
results showed that the antioxidant activity on fruit was reduced as the vibration amplitude and time
of sonication increased, while was found that vibration amplitude ultrasound and air drying temperature
were the variables that more affect the drying rate of blackberries. The drying rate increased by almost
five times when samples were treated with ultrasound at 90 lm for 20 min. They were then dried using
air at 60 C. It is concluded that the application of ultrasound in blackberry processing allows to obtain a
dehydrated product with better functional quality and shows to be effective in reducing the time
necessary to achieve a given value of moisture during convective drying.