A new mathematical model has been developed to analyze the process of drying food. The model is based on a non-linear function fit of the moisture ratio behavior. To determine the moisture ratio behavior, the Rational Polynomial method of first and second order has been proposed, which allows a simple fit that approximately describes the moisture ratio behavior. The Pearson coefficients obtained for the fitted series were greater than 0.9948. The fitting process has been automated using a simple Wolfram language script. This model has been compared against the most commonly used models and applied to a set of 39 experimental data series. The RP method for the second order showed good agreement in 82.05% of the analyzed series and was the best fit in 61.5% of all the data sets. On the other hand, the first order showed good agreement in only 30.77% of the analyzed series.