A model approach revealed the relationship between banana pulp acidity and composition during growth and post harvest ripening

Abstract

Titratable acidity and pH are important chemical traits for the organoleptic quality of banana since they are related to the perception of sourness and sweetness. Banana fruit has the particularity of having separate growth and ripening stages, during which pulp acidity changes. A modeling approach was used to understand 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/base reactions. The models were built using data from growth and post harvest ripening of three dessert banana cultivars with contrasting acidity. For each model, calculated values were compared to observed values. These models allowed the prediction of pH (R2=0.34; RMSE=0.75, biais=0.05) and of titratable acidity (R2=0.81, RMSE=2.05, biais=−1.44) during fruit growth and post harvest ripening. The sensitivity analyses showed that among acids, malic, citric and oxalic acids are the main contributors to banana pulp acidity, and that among soluble minerals, potassium also plays an important role. Studying the factors that affect the accumulation of organic acids (citric, malic, and oxalic acids) and potassium in banana pulp could be a relevant area of research with the objective of modifying banana fruit acidity.