Refractance Window™ Drying of Red Onions (Allium Cepa)
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Akinola, A. A.
Lawal, S. O.
Osiberu, A. S.
Journal of the Nigerian Society of Chemical Engineers
A Refractance Window dryer was fabricated and used to study the drying characteristics of red onions (Allium Cepa). The data for the drying of the 1mm, 2mm and 3mm sized shreds of red onions were obtained experimentally and the drying curves and mathematical model that best fit the drying data were determined. The quality of the dried red onion powder was determined and compared with dried onion powder obtained from the local supermarket. The results obtained, established that size affects the drying time of the onion samples. The 1mm sized shreds dried fastest reducing from a moisture content of 7.19kg water per kg dry solids to less than 0.2kg water per kg dry solids within 40 minutes of drying. The time of drying increased with size. Of the 13 Thin-layer drying curve models studied, the regression results showed that the Haghi and Ghanadzadeh model best describes the drying curve of the 1mm, 2mm and 3mm sized shreds with the highest coefficient of determination (R2) values of 0.99196, 0.98570 and 0.99523 respectively. The dried onion powder had a Bulk density of 0.4501 grams/ml while those of the market onion powder were 0.4616 grams/ml.
Refracture window drying , Red onions , Research Subject Categories::TECHNOLOGY::Chemical engineering
Akinola, A. A., Lawal, S. O. and Osiberu, A. S., (2014). Refractance Window™ Drying of Red Onions (Allium Cepa). Journal of the Nigerian Society of Chemical Engineers, Vol.29(1) 51-64pp.