Convective-intermittent drying of cherries preceded by ultrasonic assisted osmotic dehydration

• Convective drying of cherries in intermittent conditions.
• Effect of temperature changes on drying kinetics and cherries quality.
• Analysis of color change, the water activity.
• The cherries (Prunus cerasus L.)

This paper presents the results of experimental studies on convective drying of cherries (Prunus cerasus L.) in stationary and intermittent conditions, previously pretreated with ultrasonic assisted osmotic dehydration. The effect of a stepwise changing air temperature and osmotic pretreatment on drying kinetics and the biomaterial quality were investigated. The main aim of the studies was to find the possibly best drying conditions, by which the drying time was shortened and the product quality degradation was minimized. Except drying kinetics and total color and water activity changes, the effect of osmotic pretreatment expressed by such parameters as the Solid Gain and the Water Loss were examined. It was proved that intermittent drying of cherries preceded by ultrasonic assisted osmotic dehydration contributes to shorter drying time, better color preservation and smaller water activity.