Microwave-assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) at stationary and non-stationary conditions

This paper concerns hybrid drying of kale. Eight different schedules of drying were tested experimentally to find out the influence of microwave enhancement on the kinetics (drying rate and time), energy consumption of convective drying and quality of products. Different power of microwaves and modes of microwave application were tested. Quality of products was assesed through water activity and colour measurements, as well as retention of ascorbic acid. The results obtained in the studies allowed to state that intermittent application of high power microwave pulses may lead to a meaningful reduction of drying time and high quality of the dry products.