Optimizing Hexanal Application to Delay the Maturation of Papaya (Carica papaya cv. Solo 8) through Physicochemical Monotoring

Abstract

Background: Papaya is a climacteric fruit with high nutritional and economic value; however, its rapid ripening and short postharvest shelf life limit its marketability. Aims: This study aimed to determine the optimal timing for hexanal application in order to delay fruit maturation and extend shelf life. Study Design:  A comparative experimental trial was conducted using a factorial design involving three treatment modalities. Data obtained were subjected to analysis of variance (ANOVA). Place and Duration of Study: The experiments were carried in a papaya field between June and August 2019, and the analyses were conducted at the Laboratory of Food Biochemistry and Tropical Products Processing during the same period. Methodology: Sixty papaya plants were marked at the onset of flowering and divided into three blocks of twenty (20) plants each, identified by distinct colors. The plants were monitored until physiological maturity. Pre-harvest treatments were applied using a hexanal-based formulation at a concentration of 0.02 % on the 90th and 105th days after flowering. Three treatments were evaluated: untreated control fruits, fruits treated with hexanal at 90 days after flowering, and fruits treated at 105 days after flowering. Fruits were monitored over a six-week period. Physicochemical parameters analyzed included color indices (L*, a*, and b*), firmness, pH, vitamin C content, and soluble sugar content. Results: The results revealed that fruits treated with hexanal from the 90th day after flowering exhibited a significant delay in maturity, characterized by the maintenance of negative a* values, indicating prolonged green coloration. These fruits also retained greater firmness and significantly higher vitamin C content than the control fruits and those treated at 105 days after flowering. In addition, the increase in pH and the accumulation of soluble sugars were significantly reduced in early-treated fruits. Conclusion: Application of hexanal at 90 days after flowering delayed papaya fruit maturation on the tree by approximately two weeks. This treatment period therefore appears optimal for delaying maturity, extending fruit development, and improving harvest management.