Effect of shape on kinetics of fluidized bed drying of potato
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Date
2007
Authors
Bakal, Sushant Balasaheb
Journal Title
Journal ISSN
Volume Title
Publisher
MPUAT, Udaipur
Abstract
Potato is an important food crop. It is the fourth highest crop produced in the world. India ranks fourth in area, fourth in production and tenth in its production. The demand of potato is increasing day by day, due to population growth and food habit changes due to fast life style. Therefore processing of potato in an optimum way is necessary.
Hot air drying is commonly used practice for the drying of potato. Information is scanty on its drying kinetics with respect to shape and size. Placing the above view forth, this research work on effect of shapes on drying kinetics of fluidized bed drying of potato was undertaken. A laboratory fluid bed dryer was used, which was very convenient for drying of pieces of vegetables. Locally available potato was used in present study. The potatoes were peeled and cut in to aspect ratio1:1 (5 mm × 5 mm × 5mm), 1:2 (5 mm × 5 mm × 10 mm) and 1:3 (5 mm × 5 mm × 15 mm) for cuboidal shape and for cylindrical shape, cut to D:L ratio 1:1 (5 mm × 5 mm), 1:2 (5 mm × 10 mm) and 1:3 (5 mm × 15 mm) by using micrometer. The potatoes were immersed, immediately after cutting in a sodium meta-bi-sulphite solution (0.1% w/w) for 15 min to prevent browning which may otherwise take place during drying. The effect of process variables such as shape and air drying temperature was studied. A constant air velocity 7 m/s was used throught the experiment. The commonly used drying models such as Exponential and Page equation were fitted to drying data of potato to find their suitability.
The initial moisture content of the potato was 4.20 g H2O/g of dry matter. The complete drying took place in the falling rate period. It was inferred from the study that drying time was reduced as temperature increased for both the aspect ratio and D:L ratio. Effective moisture diffusivity increased as the aspect ratio and D:L ratio increased. The diffusion coefficient during the air drying were also determined and found that diffusivity varied from 2.278 x 10-09 to 3.314 x 10-08 m2/s. As temperature increased, effective moisture diffusivity also increased. Drying constant (k) value in Exponential and Page model were calculated using Marquardt method of non-linear regression procedure in SY-STAT (12.0) which showed that the drying constant “k” decreased as aspect ratio and D:L ratio increased. Page model gave better fit than Exponential model. Energy activation from diffusivity data were found close to the energy activation from drying data.
Description
Effect of shape on kinetics of fluidized bed drying of potato
Keywords
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Citation
Bakal and Sharma, 2007