Use of Ultrasound Pretreatment in Drying of Fruits: Drying Rates, Quality Attributes, and Shelf Life Extension

Abstract

Evolving advanced pretreatment techniques such as application of ultrasound prior to fruit drying have attracted significant research and development efforts due to the rising demand for high-quality dried fruits at reduced operating costs. Drying processes can be destructive to the quality of fruits due to long drying times and high temperatures in some cases. The effects of ultrasound pretreatment on quality aspects of dried fruits and on drying kinetics are reviewed. Ultrasound is known for its varying effects on different fruits; however, it has been proved to greatly increase drying rates and hence reduce the overall processing time. Ultrasound pretreatment in distilled water as the media is an interesting concept when low-calorie dried fruits are required.

Keywords:

• Drying
• Fruits
• Quality aspects
• Storage
• Ultrasound pretreatments

ACKNOWLEDGMENTS

The authors thank Professor Arun S. Mujumdar of the National University of Singapore for his valuable comments during the course of this work and in preparation of this article. His support and contribution are gratefully acknowledged. The authors also are grateful to the China High-Tech (863) Plan under contract No. SQ2010AA1000692004 and the National Natural Science Foundation of China (Nos. 20776062, 29206038, 20576049) for financial support.