Influence of osmoconcentration, continuous high-frequency ultrasound and dehydration on properties and microstructure of rabbiteye blueberries

Rabbiteye blueberries were osmoconcentrated for 12 h, and for 3 h with and without continuous high-frequency ultrasound (CHFU) and then air dehydrated (70 degrees C, 10 h). Osmoconcentration increased solids gain, moisture loss, soluble solids, and bulk density. Long osmoconcentration for 12 h can be reduced with CHFU with similar results. Scanning electron microscopy (SEM) micrographs indicated that berries without pretreatment suffered the highest degree of tissue collapse. They also had the highest rehydration ratio and may be ideal for use in breakfast cereals. Osmoconcentrated berries may be used as snack food or in cereal bars due to high bulk density and low rehydration ratio.