Ethephon as an Alternative Ripening Agent for ‘Cardaba’ Banana (Musa acuminata x M. balbisiana)

Abstract

Ethephon and bioethylene from Gliricidia sepium were evaluated as potential alternatives to the unsafe calcium carbide (CaC₂) in ripening ‘Cardaba’ banana. In Experiment 1, bananas were treated with CaC₂ (1 and 2 g kg^-1), G. sepium leaves (30% and 40% w/w), or ethephon (200 and 500 μL L^-1). In Experiment 2, fruit were applied with CaC₂ (2.5 or 5 g kg^-1) or ethephon (200 or 500 μL L^-1). Results showed that the use of low CaC₂ concentration (1 or 2 g kg^-1) or G. sepium leaves for 48 h was not sufficient to effectively ripen banana fruit (Experiment 1). The fruit dipped in 500 μL L^-1 ethephon for 3 min exhibited similar effect as the 5 g kg^-1 CaC₂ for 72 h, which allowed the fruit to ripen faster than the lower concentrations of CaC₂ (2.5 g kg^-1) and ethephon (200 μL L^-1), and the control (Experiment 2). The higher concentrations of ethephon and CaC₂ resulted in bananas with higher total soluble solids, least firmness, most advanced peel color after 2-3 days and least green (a^*) color that was towards the yellow hue angle. Ethephon-treated fruit had better visual quality than those treated with CaC₂ and reached the full yellow stage the earliest (4.5 to 5.8 days) compared with the other treatments (7 to 11 days). As ripening took place earlier, fruit dipped in 500 μL L^-1 ethephon solution had the least visual quality rating after seven days resulting in shorter shelf life of eight days compared with the control at 11 days.