Studying the Effect of Ultrasound Pre-treatment on drying Kiwi fruit sheets

The aim of this research was to use ultrasound pre-treatment and studying the time of drying and rehydration in dried samples of kiwifruit (Hayvard variety). The samples were dehydrated for different lengths of time, 10, 20 and 30 minutes at room temperature in distilled water in Ultrasound bath (45 kHz). The results of drying time showed that by decreasing the thickness of samples from 8 to 6 mm and increasing the ultrasound time, the time required reducing the moisture content down to 20% for each treatment. It was also found that the minimum time for bringing the moisture down to 20% in 6 and 8 mm kiwi fruits in pre-treated samples with 30 minutes sonication time was 299 and 404 minutes, respectively. The results of rehydration in samples showed that by increasing the time of sonication and decreasing the kiwifruits samples thickness from 8 to 6 mm, the rehydration increased compared to control sample. The results of organoleptic valuations about to totality acception of dried kiwifruit product showed that using pre-treated ultrasound sample was more acceptable than the control sample.