MOISTURE PROFILES IN A MODEL FOOD GEL DURING DRYING: MEASUREMENT USING MAGNETIC RESONANCE IMAGING AND EVALUATION OF THE HCKIAN MODEL
作者:
GregWarren Schrader,
J.Bruce Litchfield,
期刊:
Drying Technology
(Taylor Available online 1992)
卷期:
Volume 10,
issue 2
页码: 295-332
ISSN:0737-3937
年代: 1992
DOI:10.1080/07373939208916440
出版商: Taylor & Francis Group
关键词: Finite difference;Mass transfer
数据来源: Taylor
摘要:
Magnetic resonance imaging (MRI) was used to obtain moisture profiles of a model food gel during drying. A cylinder of gel, 1 cm in diameter, with an initial moisture content of 76% was imaged while drying at room temperature. Moisture profiles were obtained from the imaging data by imaging calibration samples of known moisture content. Signal intensity of the images was found to be highly proportional to solids content. The moisture profiles were compared to profiles predicted by a finite difference solution of Fickian radial diffusion in a cylinder. Actual moisture profiles obtained by MRI were much flatter near the center of the cylinder, with a steeper moisture profile near the edge, compared to the typical parabolic shape of the Fickian model. The Fickian model was found to be an inaccurate predictor of the interior moisture profile of the model food gel, since effective diffusivity was found to not be solely a function of moisture content. The moisture profiles obtained provide for a method to evaluate other mass transfer models, and the methods outlined provide a technique to explore mass transfer within actual food materials during processing.
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