Effect of temperature on chlorophyllase activity, chlorophyll degradation and carotenoids of Cavendish bananas during ripening

Changes in chlorophyllase activity, chlorophyll and carotenoid content of Giant Cavendish banana fruit peel during ripening were measured at tropical temperatures (30–34°C) and at 20°C to relate them to the greenish and yellow colours of the fruit ripened at these temperatures. At 30–34°C bananas remained green on ripening due to incomplete chlorophyll degradation while at 20°C complete degreening occurred and fruits turned yellow. Peel total carotenoid content remained constant during ripening and did not change with temperature. Free xanthophylls decreased while xanthophyll esters increased on ripening. Chlorophyllase activity increased during ripening and paralleled the respiratory climacteric, although activity was not consistently related to the differential degradation of chlorophyll at these temperatures. Exogenous application of ethylene and ethrel accelerated ripening, but had no effect on chlorophyllase levels, chlorophyll degradation and carotenoid content of bananas ripened at either 30–34°C or at 20°C.