This work focused on the effect of heating treatments on the sweetening property of miraculin contained in Sisrè, the fruit of Synsepalum dulcificum, from Benin. The aim was to define suitable conditions for stabilizing the fruit pulp, at a lower cost while preserving its functional properties. The fruits, collected in the locality of Sèhouè in the Republic of Benin, were frozen whole, pulped and then stored at -20 °C before processing and analyzing. Heat treatments ranging from 40 to 70 °C were applied to the fresh pulp for 5 min. Sensory tests were performed on the heated pulp samples to test the functionality of miraculin and determine the remanence time of the induced sweet taste after treatment at different temperatures. Reverse-phase and steric-exclusion chromatography, in association with electrophoresis were performed to analyze the miraculin content of the pulps, and the generated data were compared with the sensory results. Sensory analysis showed that the sweetening effect of the native pulp before heat treatment lasted at least >1 h 30 min. A significant loss of functionality after exposure of the pulp to temperature values above 50 °C was observed. The results of analyses also showed that from 50 °C, the miraculin concentration decreased significantly. At temperature values above 50 °C, miraculin completely lost its functionality even if the pulp still contained miraculin, probably in its monomeric form that are not active. The intensity and remanence of the sweetening effect of miraculin depended on its concentration. These results demonstrated that the pulp of Sisrè cannot be stabilized by thermal pasteurization and that drying at low temperatures between 40 and 50 °C could be a good technological option for preserving its functionality.