Ripening behavior and quality of 'Brazilian' bananas following hot water immersion to disinfest surface insects

Abstract

The fruit quality and ripening response of 'Brazilian' bananas (Musa sp., group AAB) were determined following hot water immersion treatments for surface disinfestation. Summer-harvested fruit were exposed to 47, 49, or 51°C water for 10, 15 and 20 minutes and ripened at 20°C. The summer experiment established the exposure time and temperature limits for fruit injury. Winter-harvested fruit were immersed in 48, 49, or 50°C water for 5, 10 and 15 minutes, stored for 12 d at 14°C, and ripened at 22°C. The hot water exposure time had a greater effect than the water temperature on banana fruit ripening. Nontreated bananas ripened after 13 to 15 d, and ripening was delayed by 2 to 7 d when fruit were exposed for 15 or 20 minutes to hot water. Hot water treatments did not inhibit pulp softening, but peels tended to be firmer for bananas immersed in 49 to 51°C water than control fruit. Heat-treated bananas were not different from control fruit in soluble solids content or titratable acidity, however the conversion of starch to sugars was reduced at higher temperatures and exposure times. Bananas exposed for 20 minutes to hot water had delayed respiratory peaks and ethylene production, especially at 51°C. Mild peel injury was observed on fruit exposed to higher temperatures (49 to 51°C) for longer durations (15 or 20 minutes).