Characterization of chlorophyll degradation in banana and plantain during ripening at high temperature

Bananas fail to fully degreen when ripening at tropical temperatures, but this abnormal symptom does not occur in plantain. To elucidate the temperature effect on banana degreening, comparison of the colour change and chlorophyll degradation pathway between banana and plantain during ripening at 20 or 30 degrees C was carried out. Compared to bananas ripening at 20 degrees C and plantains at 20 degrees C or 30 degrees C, bananas at 30 degrees C contained significantly higher levels of chlorophylls, chlorophyllide a and pheophorbide a at the end of the ripening process, linearly correlating to the colour scores of a*, b* and Hue angle. Whilst higher chlorophyllase activity was recorded in both banana and plantain at 30 degrees C as to the fruits at 20 degrees C, 30 degrees C inhibited Mg-dechelatase activity in banana, but not in plantain. The reduction of Mg-dechelatase activity in banana peel at 30 degrees C may contribute to repressed chlorophyll degradation and lead to uneven degreening. (C) 2008 Elsevier Ltd. All rights reserved.