Kinetics of moisture loss applied to the baking of snacks with pregelatinized cassava starch

Abstract

Moisture loss kinetics is a complex process defined as the liquid removal from a solid by thermal application. The purposes of the study were to obtain kinetic curves of moisture loss during the baking of cassava snacks and establish which processes govern the moisture loss, recognize which mathematical models describe the moisture loss curves more precisely, and determine activation energy (Ea) and effective diffusivity (Deff). Experimental data were obtained through baking at four temperatures formulations for snacks with different dehydrated cassava puree (DCP) proportions. Page´s and Chávez Méndez´s models showed the best fits. We calculated Deff and Ea employing the analytical solution of Fick´s Second Law for the geometry of plane plates. Deff values increase with DCP but did not show a trend. The range found was from 5.22E-06 to 2.93E-05 m2/s. The results of Ea showed that the mixture of flours produced an increase in the energy necessary to initiate the effective diffusion (24.84 kJ/mol) compared to the samples without mixing (15.54 kJ/mol). Moisture loss curves show that the diffusion process governs a large part of the process.