FREEZE-DRYING OF THE BLACK-CURRANT JUICE

The effect of drying temperature of the black currant juice on the retention of vitamin C and anthocyanins content as well as drying kinetics in the freeze-dried process, has been studied. Non clarified, black currant juice was freezed on plates in the layer of 15 mm thick until the temperature of -30 degrees C in the thermal center of sample has been reached. Plates with frozen layers of juice were subject of freeze-drying process at 5 different temperatures of the heating plate (20, 30, 40, 50 and 60 degrees C). Studies of the retention of vitamin C and anthocyanins after, drying were carried out. Freeze-drying of black currant juice should be carried out at the temperature not higher than 40 degrees C to preserve content of vitamin C and anthocyanins.