Cooking bananas are staple food for million inhabitants worldwide. Starch is the main component of cooking bananas and plantains at green stage of maturity. the cooking process needed for the consumption of cooking banana is often applied in excess water, leading to an irreversible order-disorder transition of starch, namely gelatinization. Both water and thermal conditions applied are known to affect the functional quality of starch and of the final product, including its nutritional quality. Thus, various thermo-hydric conditions were applied to investigate the thermal transitions linked to starch gelatinization, with temperature and water content ranging 55-120°C and 1.4-2.0 kg.kg-1 of dry starch. A banana flour-water mixture was characterized using DSC while taking into account the effective glass transition temperature, and using a hermetically sealed test cell to get an equivalent extent of starch gelatinization. The coresponding digestibility was evaluated using an in vitro technique. A powerful predictive mathematical tool was developed for monitoring the starch digestibility during process while optimizing its nutritional quality. The degree of plantain starch gelatinization was revealed being mainly dependent on temperature in non-limiting water conditions (> 70% moisture content, wet weight basis). Different thermo-hydric conditions resulted in the same digestibility values, i.e. higher temperatures compensated lower moisture contents, and vice-versa, to reach similar digestibility properties.