DETERMINATION OF MOISTURE DIFFUSIVITY OF RED DELICIOUS APPLE TISSUES BY THERMOGRAVIMETRIC ANALYSIS
作者:
H. Feng,
J. Tang,
St. John Dixon-Warren,
期刊:
Drying Technology
(Taylor Available online 2000)
卷期:
Volume 18,
issue 6
页码: 1183-1199
ISSN:0737-3937
年代: 2000
DOI:10.1080/07373930008917771
出版商: Taylor & Francis Group
关键词: apple;moisture diffusivity;thermogravimetric analysis;dehydration
数据来源: Taylor
摘要:
Moisture diffusivity is an important parameter needed in the analysis, design and optimization of drying processes for food and other materials. Published data on moisture diffusivities of food materials are scarce and, sometimes, inconsistent due to a lack of a precise and repeatable experimental technique. Most experimental data are limited to low and moderate drying temperature (<70°C), whereas in the food industry hot air of up to 100°C is usually used in the falling rate period to speed up the drying processes. In this study, the effective moisture diffusivities of Red Delicious apple tissues were determined from drying curves produced with a Perkin Elmer thermogravimetric analyzer, using the slope method. The experiments were conducted at lour temperatures 60, 80, 100 and 120°C. Two well defined falling rate periods were observed. The effective moisture diffusivity, for the four temperature levels ranged from 3.2 × 10−7to 7.9 × 10−8m2/s for the first falling rate period and 3.8 × 10−8to 4.7 × 10−8m2/s for the second falling rate period. The temperature dependence of the effective diffusivity can be described with an Arrhenius-type equation.
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