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Moisture diffusivity and water activity of part‐baked bread at above and sub‐freezing temperatures
Author(s) -
Hamdami Nasser,
Monteau JeanYves,
Bail Alain Le
Publication year - 2006
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2005.00984.x
Subject(s) - thermal diffusivity , moisture , water activity , extrapolation , thermodynamics , water content , mass diffusivity , chemistry , mass transfer , materials science , geology , composite material , geotechnical engineering , mathematics , physics , mathematical analysis
Summary Accurate values of the effective moisture diffusivity and water activity of foodstuffs are necessary in order to study mass transfer and the weight loss during freezing. This work focuses on the evaluation of the effective moisture diffusivity of part‐baked bread and its crumb and crust and of the water activity of the part‐baked bread crust. The effective diffusivities have been estimated by analyses of drying data on the bread and crumb samples. They were related to the temperature by the Arrhénius relationship. Water activity was experimentally determined at positive temperatures. Experimental data were modelled by the Guggenheim–Anderson–de Boer (GAB) model and a model deduced from the Clausius–Clapeyron equation. The results predicted by the Arrhénius and GAB models showed a good agreement with the experimental values. Finally, the moisture diffusivity and water activity in the subzero domain were obtained by extrapolation using an Arrhénius model and a GAB model, respectively.