Effect of ultrasound treatment on the water state in kiwifruit during osmotic dehydration

卷:144

Nowacka, M. ; Tylewicz, U. ; Laghi, L. ; Rosa, M. Dalla ; Witrowa-Rajchert, D.

Warsaw Univ Life Sci

关键词: Kiwifruit;    Ultrasound;    Osmotic dehydration;    Water state;    TD-NMR;    Structure;   

DOI  :  10.1016/j.foodchem.2013.05.129

学科分类：食品科学和技术

【 摘 要 】

The present work investigates how ultrasound pretreatment modulates the effects of osmotic dehydration (OD) on the water state and microstructure of kiwifruit. Kiwifruit slices (10 mm thick) were subjected to ultrasonic waves in a water bath at a frequency of 35 kHz for 10, 20 and 30 min. OD process was then carried out by immersing the samples in 61.5% sucrose solution equilibrated at 25 degrees C for a contact period of 0, 10, 20, 30, 60 and 120 min. The partition of water into the cellular tissue structures (vacuole, cytoplasm, extracellular spaces and cell wall) was investigated by Time Domain Nuclear Magnetic Resonance (TD-NMR). In parallel, the microstructure of kiwifruits slices was examined using a Scanning Electron Microscope. The results showed that US pretreatment performed for more than 10 min had a positive effect on the mass exchange caused by osmotic dehydration. A creation of microchannels and an increase of the average cross-section area of cells were observed when the samples were pretreated with US before OD. TD-NMR showed a slight redistribution of water through the substructures of the cells, as a function of the length of the US pretreatment applied. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.