نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Turnip (Brassica rapa L.) is a nutritionally valuable root vegetable, and preserving its quality during postharvest processing is of considerable importance. In this study, microwave drying behavior of turnip slices was experimentally investigated at three microwave power levels (550, 770, and 990 W), and moisture transfer characteristics were analyzed using the classical Fick diffusion model and the Dincer–Dost model. Drying kinetics, effective moisture diffusivity, surface mass transfer coefficient, Biot number, and activation energy were determined from experimental data.The results showed that increasing microwave power significantly reduced drying time and enhanced moisture removal. Effective moisture diffusivity increased with power in both models, ranging from 3.83×10-9 to 1.78×10-8 m2/s for the Fick model (with a correlation coefficient R2 of the higher power, respectively: 0.98, 0.98 and 0.96) and from 1.16×10-9 to 8.74×10-8 m2/s for the Dinser–Dost model. The calculated Biot numbers (0.88–1.30) indicated a mixed control regime, where both internal diffusion and surface mass transfer resistances are significant. The Dincer-Dost model provided a more realistic physical interpretation of mass transfer by explicitly distinguishing between internal moisture diffusion and surface mass transfer resistance, and by using the Biot number calculation.These findings contribute to improved modeling, optimization, and scale up of microwave drying processes for agricultural products.
کلیدواژهها English