Mathematical modeling of convective air drying of quinoa-supplemented feed for laboratory rats

Drying kinetics of quinoa-supplemented feed for laboratory rats during processing at 50, 60, 70, 80 and 90°C was studied and modeled in this work. Desorption isotherm was obtained at 60°C giving a monolayer moisture content of 0.04 g water/g d.m. The experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying equations available in the literature were evaluated based on determination coefficient (r²), sum squared errors (SSE) and Chi-square (χ²) statisticals. In comparison to the experimental moisture values, the values estimated with the Logarithmic model gave the best fit quality (r² >0.994, SSE < 0.00015 and χ² < 0.00018), showing this equation could predict very accurately the drying time of rat feed under the operative conditions applied.