超声在食品干燥领域中的研究进展

如何快速而经济地干燥物料并获得高品质的产品,是干燥领域需要解决的核心问题。目前传统单一的干燥技术在一些方面已无法满足实际需求,探索各种干燥技术的组合成为近年来的研究热点。功率超声(声强大于1 W/cm_²)作为一种绿色、无污染的物理加工方法,在干燥过程中强化水分的传热和传质方面已显示出独特的优越性,在食品干燥领域方面具有广阔的应用前景。本论文主要介绍了超声在食品干燥前预处理、超声强化渗透脱水、超声耦合热风干燥、超声耦合喷雾干燥、超声耦合冷冻干燥、超声耦合热泵干燥、超声耦合太阳能干燥等方面的研究进展,分析了超声干燥的作用效应及机理,总结了超声干燥的优点并指出目前存在的问题及今后的研究方向。

Progress of Food Drying Assisted by Power Ultrasound

Drying is an important unit in food processing. In recent years, drying technology is developing towards high standards of energy saving, high efficiency and further improvement of product quality. It is a very promising direction to explore the strengthening of drying process and the coupling of various drying technologies. Ultrasonic refers to sound waves of with a frequency of 2×10_⁴ Hz to 1×10_⁹ Hz. Compared to other frequency of sound waves, ultrasonic has many advantages of strong propagation direction, high vibration acceleration of medium particles and cavitation in liquid medium. Due to the unique effect of ultrasound, it has been widely used in many fields as a very effective enhancement means. In view of the remarkable effect and potential applications of ultrasound in enhancing heat and mass transfer, it has attracted more and more attention in food drying in recent years. This paper mainly introduces the recent progress of ultrasonic drying techniques, including ultrasonic pretreatment before food drying, ultrasonic enhancement of osmotic dehydration, ultrasonic coupling hot air drying, ultrasonic coupling spray drying, ultrasonic coupling freeze drying, ultrasonic coupling heat-pump drying, and ultrasonic coupling solar drying. The effect, mechanism and advantages of ultrasonic drying are analyzed, and the existing problems and the direction of future development are presented.