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

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 degrees C for 6h 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.