Characteristics of chard leaves during microwave, convective, and combined microwave-convective drying

Abstract

Chard leaves (Beta vulgaris L. var. cicla), which weighs 25g with a moisture of 9.35 (db), were dried using three different drying methods, microwave, convective, and combined microwave-convective. Drying continued until leaf moisture fell down to 0.1 (db). Drying periods lasted 5-9.5, 22-195, and 1.5-7.5 min for microwave, convective, and combined microwave-convective drying, respectively, depending on the drying level. In this study, measured values were compared with predicted values obtained from Page's semi-empirical equation. Optimum drying period, color, and energy consumption were obtained for combined microwave and convective drying. The optimum combination level was 500W microwave applications at 75 degrees C.