Department of Food Science and Technology, University of Tabriz, Tabriz 51666-16471, Iran.
Department of Food Science and Technology, University of Tabriz, Tabriz 51666-16471, Iran.
Ultrasonics. 2019 Jul;96:104-122. doi: 10.1016/j.ultras.2019.02.005. Epub 2019 Feb 14.
The objective of this study was to intensify combined intermittent microwave - low temperature (40 °C) hot air drying with ultrasound. The process variables were ultrasound time (40 kHz for 0, 10, 20 and 30 min), microwave power (360, 600 and 900 W), and microwave pulse ratio (1, 2, 3 and 4). Results showed that the highest reduction in moisture content was observed in the samples pretreated with ultrasound for 10 min and then dried at 900 W microwave with the pulse ratio of 4. As ultrasound time, microwave power and pulse ratio increased, significant increases were noticed in D by 4.89, 16.44 and 20.7%, respectively. Moreover, shrinkage was lower in the samples pretreated with lower ultrasound time and microwave pulse ratio. Besides, bulk density reduced when the microwave power was increased due to lower volume reduction. In addition, the highest increase in rehydration (32.23%) was observed in the samples dried using the high-power intermittent microwave. Finally, the highest significant reduction in specific energy consumption as a result of increased microwave power was 23.32%. In general, results of this study demonstrated that the ultrasound-intensified combined intermittent microwave - low temperature hot air drying may be a suitable alternative for industrial applications.
本研究的目的是强化超声联合间歇微波-低温（40°C）热空气干燥。过程变量包括超声时间（40kHz 分别为 0、10、20 和 30min）、微波功率（360、600 和 900W）和微波脉冲比（1、2、3 和 4）。结果表明，经 10min 超声预处理后，在 900W 微波和 4 的脉冲比下干燥的样品水分含量降幅最大。随着超声时间、微波功率和脉冲比的增加，D 值分别显著增加了 4.89%、16.44%和 20.7%。此外，经较低超声时间和微波脉冲比预处理的样品收缩率较低。此外，由于体积减小，微波功率增加会导致堆密度降低。此外，在使用高功率间歇微波干燥的样品中，复水率（32.23%）最高。最后，由于微波功率的增加，比能耗显著降低了 23.32%。总的来说，本研究结果表明，超声强化联合间歇微波-低温热空气干燥可能是一种适合工业应用的替代方法。
