Improving the infrared drying and rehydration of potato slices using simple approaches: Perforations and ethanol

AbstractThe objective of this work was use ethanol and perforations as simple approaches to improve the infrared drying and rehydration of potato slices. Perforations were performed to study the effect of promoting routes to capillarity flow, while ethanol was impregnated in the samples to evaluate the effect of Marangoni flow. All pretreatments reduced the drying time compared to control treatment. However, a great time reduction was observed with P + E pretreatment: The synergistic combination of both treatments increased the drying rate in more than four times, reducing both drying time and the necessary energy by 44%. The samples with perforations (P and P + E) increased their rehydration rate as well as the water retention capacity. However, the pretreated samples with ethanol shows poor rehydration properties. Possible mechanisms were discussed. These results show simple approaches to enhance food drying and rehydration.Practical ApplicationsDrying is an ancient unit operation to obtain safe and stable food products. However, some challenges still face food process engineers, such as the long processing time and the low rehydration capacity. Consequently, different technologies have been explored to enhance food drying, such as pulsed electric fields, high pressure, and ultrasound. However, although interesting and effective, some of that approaches can be complicated or even expensive when considering the reality of drying vegetables such as fruits and starchy products, limiting their application. Therefore, this work purposes a simple but efficient technique based on the use of ethanol and the creation of channels through perforations to improve the infrared drying of potato slices, also evaluating the rehydration properties. Our results show that simple operations could be performed to create routes to water flow (through mechanical perforations) combined with drying accelerator (ethanol), improving both drying and rehydration of food products.