Numerical Simulation of Variable Water Diffusivity during Drying of Peeled and Unpeeled Tomato

Xanthopoulos, G; Yanniotis, S; Boudouvis, AG

dc.contributor.author	Xanthopoulos, G	en
dc.contributor.author	Yanniotis, S	en
dc.contributor.author	Boudouvis, AG	en
dc.date.accessioned	2014-03-01T11:47:06Z
dc.date.available	2014-03-01T11:47:06Z
dc.date.issued	2012	en
dc.identifier.issn	00221147	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/38085
dc.subject	Nonlinear water diffusion	en
dc.subject	Numerical simulation	en
dc.subject	Peeling effect	en
dc.subject	Tomato air-drying	en
dc.title	Numerical Simulation of Variable Water Diffusivity during Drying of Peeled and Unpeeled Tomato	en
heal.type	other	en
heal.identifier.primary	10.1111/j.1750-3841.2012.02908.x	en
heal.identifier.secondary	http://dx.doi.org/10.1111/j.1750-3841.2012.02908.x	en
heal.publicationDate	2012	en
heal.abstract	A mathematical model was formulated for the estimation, in conjunction with experimental measurements, of water diffusivity parameters during convective drying of peeled and unpeeled tomatoes. Fick's 2nd law of diffusion was solved numerically for a sphere, by explicit finite differences, considering shrinkage effect, variable diffusivity, and constant boundary conditions. Experiments were performed in a laboratory tunnel dryer. The equivalent radius of tomato decreased by 50% until the end of the process, which explains the necessity for shrinkage inclusion in the mass transfer model. The mean estimated diffusivities varied between 2.03 × 10-10 and 15.1 × 10-10 m2/s for peeled tomatoes and 0.59 × 10-10 and 15.2 × 10-10 m2/s for unpeeled tomatoes. The estimated water diffusivities and their variation with the tested drying temperatures (45, 55, and 65 °C) provide an insight of peeling effect during air-drying. Peeling was beneficial since yielded greater drying rates and shortened significantly drying times, thus saving energy during drying. In all the studied cases, good agreement was found between experimental and predicted drying curves (≥ 0.99, mean relative deviation [MRD]≤ 0.12, and root mean square error [RMSE]≤ 0.03). In overall, the proposed methodology provides a reliable and easy estimation of temperature and moisture-dependent mass transfer properties and drying simulation of shrinkable food products such as tomato. © 2012 Institute of Food Technologists®.	en
heal.journalName	Journal of Food Science	en
dc.identifier.doi	10.1111/j.1750-3841.2012.02908.x	en