Effect of different levels of Sigatoka disease severity on banana pulp colour and early ripening

Abstract

Bananas are usually harvested at a green preclimacteric stage prior to sale. The preclimacteric phase is called green life (GL), which is defined as the number of days between harvesting and initiation of the natural ripening process. Sigatoka disease (SD) has previously been shown to influence the postharvest behaviour of banana fruit. This work was set out to determine whether there is a relationship between the level of SD severity and the extent of the effects on banana quality as characterized by several pomological traits, especially pulp colour. In an experiment conducted with fruits harvested at a constant physiological age, our results showed that SD had a major effect on the percentage of fruit ripening in the field and on fruit weight, but not on fruit diameter. We showed too that pulp colour was greatly affected by SD; when severity increased, pulp colour parameters were modified – L* (lightness) decreased, a* (axis red to green) and b* (axis yellow to blue) increased, giving a more greyish pulp colour, with less green and more yellow and red. These results may enable the development of a method for controlling fruit quality, by measuring pulp colour in the field, in order to reduce post-harvest losses.