Original scientific paper
https://doi.org/10.17508/CJFST.2020.12.2.04
Influence of temperature and thickness on thin layer drying characteristics of onion (Allium cepa L.) varieties and rehydration capacity
SUNDAY SAMUEL SOBOWALE
orcid.org/0000-0002-1051-1133
; Department of Food Technology, Moshood Abiola Polytechnic, PMB 2210 Abeokuta, Ogun State, Nigeria
OLUWOLE BENJAMIN OMOTOSO
; Department of Food Technology, Moshood Abiola Polytechnic, PMB 2210 Abeokuta, Ogun State, Nigeria
YUSUF OLAMIDE KEWUYEMI
orcid.org/0000-0003-3294-245X
; School of Tourism and Hospitality, College of Business and Economics, University of Johannesburg, P. O. Box. 524, Bunting Road Campus, Gauteng, South Africa
OLAWALE PAUL OLATIDOYE
orcid.org/0000-0002-6926-9724
; Department of Food Technology, Yaba College of Technology, PMB 2011, Yaba, Lagos, Nigeria
Abstract
Nonlinear regression analysis was conducted for thin layer drying characteristics of two onion varieties (white and red) and some quality characteristics were also examined. The experimental data obtained at drying temperatures of 40, 50, and 60 oC and thicknesses of 2, 4 and 6 mm, was subsequently fitted into four commonly used models (Henderson and Pabis, Lewis, Page, and logarithmic). Moisture diffusivity and activation energy ranged from 8.9 × 10-10 to 8.4 × 10-9 m2/s and 55.98 to 65.68 KJ/mol, respectively. Significant differences (p<0.05) were observed in the colour profile and rehydration ratio. The optimum desirable colour was obtained at
50 oC with 2 mm thick onion slices and the observed higher rehydration ratio indicates good quality of dried onions. Among the four selected drying models, the Page model predicted optimally (R2 > 0.9) and was found to be better in describing dried onion varieties, while the Lewis model provided the least fit.
Keywords
onions; drying; thickness; temperature; models; rehydration
Hrčak ID:
248535
URI
Publication date:
30.11.2020.
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