Ethanol and ultrasound pre-treatments to improve infrared drying of potato slices

Ethanol and ultrasound (US) were applied as pre-treatments to improve the infrared (IR) drying of potato slices. Pre-treatments included Control samples (Without any pre-treatment), samples immersed in ethanol (Ethanol treated) and treated with US using ethanol (Ethanol + US) and water medium (Water + US). Effects on microstructure, drying, rehydration, and viscoelasticity were studied. Microstructure analyses suggested that ethanol affected the potato cell wall. The Water + US pre-treatment impacted the starch granules dispersion inside cells. However, higher modifications were observed when Ethanol + US was applied. Compared to the Control, all pre-treatments decreased the drying time, while Ethanol + US provided the highest reduction. In contrast, a slight decrease in rehydration properties was observed. The dried and rehydrated samples presented similar viscoelasticity among them but differed significantly with the in-natura (fresh potato) samples. Possible mechanisms were discussed. The results open new perspectives about an innovative method to improve drying.