Titratable acidity and pH are important chemical traits for the organoleptic quality of banana since theyare related to the perception of sourness and sweetness. Banana fruit has the particularity of havingseparate growth and ripening stages, during which pulp acidity changes. A modeling approach was used tounderstand the mechanisms involved in changes in acidity during pulp growth and post harvest ripening.Changes in pH and titratable acidity were modeled by solving a set of equations representing acid/basereactions. The models were built using data from growth and post harvest ripening of three dessertbanana cultivars with contrasting acidity. For each model, calculated values were compared to observedvalues. These models allowed the prediction of pH (R2= 0.34; RMSE = 0.75, biais = 0.05) and of titratableacidity (R2= 0.81, RMSE = 2.05, biais = ?1.44) during fruit growth and post harvest ripening. The sensitivityanalyses showed that among acids, malic, citric and oxalic acids are the main contributors to banana pulpacidity, and that among soluble minerals, potassium also plays an important role. Studying the factorsthat affect the accumulation of organic acids (citric, malic, and oxalic acids) and potassium in bananapulp could be a relevant area of research with the objective of modifying banana fruit acidity.