DRYING KINETICS, HEATING UNIFORMITY AND QUALITY CHANGES DURING THE MICROWAVE VACUUM DRYING OF ARTICHOKES (CYNARA SCOLYMUS L.)

Mustu, C; Eren, I

DRYING KINETICS, HEATING UNIFORMITY AND QUALITY CHANGES DURING THE MICROWAVE VACUUM DRYING OF ARTICHOKES (CYNARA SCOLYMUS L.)

Authors

Mustu, C

Eren, I

Publisher

CHIRIOTTI EDITORI

Abstract

In this study, our aim was to investigate the effect of process parameters such as the microwave power (450-800 W), system pressure (12.40 - 31.20 kPa) and drying time (0-25 min) on the drying kinetics, quality characteristics and heating uniformity indices during the microwave vacuum (MV) drying of artichokes. The microwave power was found to be more influential than the system pressure, and variations resulted in different drying characteristics. The effective diffusion coefficients were found to range from 2.279x10(-6) - 3.454x10(-6) m(2)/s and 3.600x10(-) - 6.297x10(-) m(2)/s for the first and second falling rate periods, respectively. Reducing microwave power and system pressure resulted in higher uniformity in temperature distributions. However, the average temperatures deviated slightly from the targeted drying temperatures at high microwave power. The highest shrinkage coefficient (0.3705 +/- 0.0233) and rehydration ratio (3.82 +/- 0.091) values were obtained at 800 W and 12.4 kPa. MV drying preserved the fresh colour characteristics of artichokes, and it could be used as an alternative to conventional drying.