Optimization of drying kinetics of broccoli (Brassica oleracea L.)

Abstract

The aim of this paper was to optimize the technological process of broccoli drying. The drying experiment were carried out in the laboratory dehydrator, at two temperature regimes of drying, batch process (constant air temperature of 70 °C for a period of 8h) and simulated continual process (the air temperature of 70 °C for a period of 3h and then the air temperature of 50 °C for a period of 5h). The amount of evaporated water was expressed in relative and absolute units of measure. The experiment was conducted to follow the moisture rate of drying of broccoli and was expressed as speed changes in the ratio of moisture content in the moist material depending on the current moisture content. The results showed that in simulated continual process of drying the lower maximum moisture rate of drying was achieved, drying was more evenly and in this way the technological process was finished with a smaller temperature stress for plant tissue, resulting in a better quality of the final product. The second temperature regime of draying, which simulated continual process, was more acceptable in terms of the final product.