EXPERIMENTAL RESEARCHES ON SOME SPECIES AND VARIETIES OF FRUITS AND VEGETABLES SUBJECTED TO DEHYDRATION TREATMENTS

Abstract

The main objective of the work is the study of the process of dehydration of fruits and vegetables, using two different types of equipment for dehydration: convective dryer, equipped with drying trays; microwave field dehydration instalation, with continuous flow. In the case of the convective dryer, the divided products will be placed evenly on the drying trays and the following specific parameters of the dehydration process will be determined: the initial and final humidity of the products; initial and final air temperature; the initial and final humidity of the air. In the case of microwave dehydration equipment, the divided products will be placed in a uniform layer on the conveyor belt, which moves at a constant speed of 4.5 cm/min. The following parameters will be measured: the mass of the sample; the amount of water evaporated in the measuring interval; the final mass of the sample; the final humidity at the end of the dehydration cycle. The results obtained in the case of using the convective dryer with drying trays indicate that the measured values fall perfectly within the admissibility range imposed by the technology,regarding all the studied parameters. In the case of using the dehydration installation with microwaves, the dehydration process is very intense, producing rapid heating of the product to over 600 C⁰, in approx. 5 min., in its entire volume, which leads to the inactivation of oxidative enzymes and reduces the risk of thermal browning and caramelization.