Evolution of soluble sugars during ripening of papaya fruit and its relation to sweet taste

Fruit ripening is closely associated with compositional and structural changes which can occur before or after harvesting. In papaya fruit, the period of sugar synthesis and accumulation remains poorly understood. The correlation between soluble sugar content and sweetness during papaya ripening was investigated in this study. Soluble sugars accumulated mainly when the papaya fruit was still attached to the plant. After harvest, however, there was still sucrose synthesis, and the sucrose-phosphate synthase activity was highly correlated to the sucrose content, indicating the importance of this enzyme in the process. Sensory analysis showed that there was a dissociation between sugar content and sweet sensory perception, while the pulp softening showed high correlation with the sweetness process, probably due to the easier release of cellular contents in the fully ripened tissue.