A novel method of osmotic-dehydrofreezing with ultrasound enhancement to improve water status and physicochemical properties of kiwifruit

A novel method of osmotic-dehydrofreezing with ultrasound enhancement to improve water status and physicochemical properties of kiwifruit was investigated. Kiwifruit were subjected to osmotic dehydration with different ultrasound power (20 kHz, 0-300 W) at 30 degrees C for 30 min, and then frozen as well as stored at -18 degrees C. The results showed that osmotic dehydration with ultrasound enhancement increased water loss and solid gain, and maintained the cell structure. Osmotic dehydration with ultrasound enhancement also reduced freezable water content and decreased water mobility in comparison to osmotic dehydration alone. Osmotic dehydration with ultrasound application prior to freezing shortened the freezing time, decreased drip loss, maintained ascorbic acid content and firmness, preserved the flavor and improved the taste for kiwifruit after freezing and thawing compared to control. Therefore, these results demonstrated that the osmotic-dehydrofreezing with ultrasound application can effectively increase freezing rate and improve the physicochemical properties of kiwifruit in freezing and thawing processes. (C) 2020 Elsevier Ltd and IIR. All rights reserved.