Effect of Osmotic Dehydration on Microwave Freeze-Drying Characteristics and Quality of Potato Chips

Abstract

In this study, the effects of osmotic pretreatment on microwave freeze-drying (MFD) characteristics and quality of potato chips were studied. Potato slices were pretreated by immersion in salt solution (5, 10, 15% w/w) or sucrose solution (30, 40, 50% w/w) at 20°C for 6 h prior to MFD. Results showed that osmotic pretreatment significantly improved the MFD drying rate compared with MFD of fresh samples under the same operating conditions. However, there is an optimal level of osmotic dehydration beyond which it has an adverse effect on product quality. Osmotic pretreatment with salt concentration below 5% and/or sucrose concentration below 30% prior to MFD drying resulted in dried products of good quality with shorter total drying times relative to MFD of untreated samples.

Keywords:

• Drying kinetics
• Microwave freeze drying
• Osmotic dehydration
• Potato
• Quality

ACKNOWLEDGMENTS

The authors express their appreciation to Frito-Lay Inc., Plano, Texas, for the financial support of this study. Discussions with Dr. Ted Farrington were very valuable during the course of this work. His support and contribution are gratefully acknowledged. The authors also thank the National Natural Science Foundation of China (No. 20776062) and 863-HI-TECH Research and Development Program of China (No. 2007AA100406) for the financial support of the equipment.

Notes

Note. Different letters in the same column indicate a significant difference (p ≤ 0.05); the results are average value of five replicates ± standard deviation.

Note. Different letters in the same column indicate a significant difference (p ≤ 0.05).