Modelling water absorption of pasta during soaking

Rehydration of pasta at 20, 40, 60 and 80 degrees C was examined using Fick's Second Law of Diffusion to describe the rehydration kinetics. The process was characterized by two effective diffusion coefficients (D-1, D-2). The effect of temperature on D was interpreted using the Arrhenius relationship. Application of the Peleg and Weibull models were investigated for predicting water absorption of penne pasta. It was shown that the Peleg constants k(1) and k(2) decreased with temperature. The Weibull parameter, alpha, was constant with temperature, while the kinetic parameter, beta, decreased with increasing temperature (40-80 degrees C). On rehydration, dry pasta changed from a homogeneous, porous structure with few visible starch granules, to a porous structure containing swollen starch granules held within a protein matrix. At an elevated temperature (80 degrees C), the structure then developed into an open network of coagulated protein. Sample diameter increased on rehydration, with the magnitude of the volume increase increasing with temperature and time. (C) 2007 Elsevier Ltd. All rights reserved.