The process of extracting the bixin colorant produces a large amount of residual annatto seeds that, in most cases, has been discarded by the industries. The objective of this study was to dehydrate residual grain flour of annato, with and without the oil layer originated of the extraction process of the pigments in an oven with forced air circulation at 40, 50, 60 and 70 ºC temperature and to adjust the mathematical models of the Diffusion Approximation, Two Terms, Midilli, Page and Thompson to the experimental data. Residual grain flour of annato with water content approximately 20% w.b. was dried to the final water content of about 5% w.b. As a criterion for evaluating the adjustment of mathematical models the coefficient of determination and mean-square deviation were used. It was found that samples of flour with oil demanded longer time to achieve moisture content of 5% w.b. in comparison to samples of flour without oil. All studied models accounted satisfactorily drying kinetics of flour with and without oil, with determination coefficients above 0.95 and values of mean-square deviation below 1.0.
Bixa orellana L.; byproduct; dehydration; mathematical modeling
