Laser-induced fluorescence spectral analysis of papaya fruits at different stages of ripening.

Abstract

Laser-induced fluorescence (LIF) spectra were obtained from Maradol papaya fruits at harvested mature, harvested immature, different ripeness stages, and during the ripening. The chlorophyll fluorescence of papaya fruits showed two maxima; one in the red at 680-690 nm (F690), and the other in far-red region at 730-740 nm (F740). The fruits that were harvested immature showed a definite increase in fluorescence intensity at both maxima within the first six days. The fluorescence emission spectra and fluorescence ratios F690/F740 were analyzed. Results showed that intensity and spectral shape are characteristics of different ripeness stages and during the ripening. The values obtained from F690/F740 showed a direct relation with the fruit harvested mature, harvested immature, and fruit in the ripening process. These results demonstrated that LIF is a useful tool for nondestructive monitoring of the changes in chlorophyll content and photosynthetic activity caused by the different ripeness stages and during the ripening of papaya fruits.