DETERMINATION OF MOISTURE DIFFUSIVITY AND BEHAVIOR OF TOMATO CONCENTRATE DROPLETS DURING DRYING IN AIR |
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| Authors: | Şükrü KARATAŞ Ali ESIN |
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| Affiliation: | 1. Food Engineering Department , University of Gaziantep , Gaziantep, 27310, TURKEY;2. Food Engineering Department , Middle East Technical University , Ankara, TURKEY |
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| Abstract: | ABSTRACT The drying mechanism and diffusion coefficient of water in spherical droplets (1.73 – 2.08 mm diameter) of tomato concentrates were successfully interpreted and modelled by using Fick's law. Solids content of the initial concentrate (5–15% w/w), and drying temperature (60° – 100° C) were varied but the drying air was kept at constant velocity and humidity. The effective moisture diffusivity was estimated from the drying rate curves and expressed by an Arrhenius relation. Further, it was observed that case hardening has a large effect on the diffusion process causing the effective diffusional distance and the rate of moisture accumulation in the hardened crust to vary with the moisture content, according to a sorption controlled mechanism. |
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| Keywords: | case hardening drying chamber drying rate glass ball Plasticizing sorption spherical |
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