Modelling Matambu bean (Phaseolus vulgaris) hydration kinetics using an automated digital image analysis

Common bean is one of the most consumed crops worldwide and of great importance for food security in Central America. In Costa Rica, there is not much information regarding the physical properties of the relatively new variety of Matambu bean. The aim of this study was to determine the speed in which Matambu bean (Phaseolus vulgaris) expands after grain soaking. An automated digital image processing pipeline for measuring individual grain volume and simultaneously retaining its integrity was validated and used. The previously described pipeline uses a mirror at 45 degrees so that a superior and lateral image could be taken and the 3 perpendicular diameters that compose a triaxial ellipsoid could be measured from grains. The geometric distances where calibrated with known geometries with high correlations (R² =0.999) and the approximated volume was validated with a pycnometer with an average difference of 16 %. Volumetric expansion was evaluated with Peleg and sigmoid models for water temperatures of 20-70 °C. The equations kinetic parameters were described as functions of temperature using the Arrhenius equation with an activation energy of 22.410 kJ mol^-1. The obtained results are potentially useful for future studies on food properties, grain quality, process, and packaging design. (author)