Modeling and thermodynamic analysis of the hydration and germination of triticale seeds

Abstract

We investigated the hydration and germination of triticale seeds to improve process efficiency and product quality. The grains were hydrated in a water bath at 20–50 °C for 15 h. Temperatures of 20 °C–30 °C and process times as of 660 min provided the best hydration rates without hindering the germination capacity of the seeds. Throughout processing, we monitored the moisture uptake and volumetric expansion of the samples by gravimetric methods. A tracer pigment added to the hydration water and the images obtained with scaning electron microscopy elucidated the mechanisms of moisture uptake throughout the grains. The water penetrated the grain primarily through the micropyle, a region of high porosity. The mass transfer (diffusion coefficient) and thermodynamic properties (enthalpy, entropy, and Gibbs free energy) indicated the process is non-spontaneous and endothermic. Such piece of information is helpful in equipment design. We also proposed mathematical models, based on Fick's Law of Diffusion, that predict the moisture content of cereal seeds hydrated at 20–50 °C for up to 15 h with great accuracy (P ≤ 3.36% and RMSE≤1.54%).