26. Predictive Modeling of Textural Quality of Almonds During Commercial Storage and Distribution

The textural properties of almonds may be assessed using a predictive model consisting of the moisture adsorption isotherms, Fick’s second law of water diffusion, and Fermi’s distribution function. The experimental data of moisture adsorption and the mechanical properties of almonds were measured and fitted into the preceding three models, respectively. A GAB model was used to describe the equilibrated moisture contents of almonds under different temperatures and water activity (a _w) levels; the diffusion coefficients (D _eff) of water in almonds were determined using Fick’s second law; Fermi’s distribution function was used to describe the relationship between the mechanical properties and a _w at different temperatures. A computer-aid model was developed to calculate the moisture content and the mechanical properties (fracture force, toughness, stiffness, firmness) of almonds during storage using the coefficients of each model and initial conditions (initial moisture content, relative humidity, and temperature).