Application of Vis-NIR spectrometer on assessment of fruit maturation and ripening using spectral indicies

Spectral indices can be used in assessment of pigment level of intact plant material, and thus there exits the possibility of using such indices as a measure of fruit maturity and ripeness. Spectra of tomato, banana and mango fruit were collected with a Nirvana handheld unit (Integrated Spectronics, Australia). A number of spectral indices: red edge, being point of inflection of chlorophyll peak; Greenness index = A554/A677; DA index = A670-A720; Chlorophyll index = A800/A700-1; Car/Chl ratio = (A678-A500)/A750; Chlorophyll ratio = A750/A700 and Xanthophyll index = (A530-A570)/(A530+A570), Mango index 1= (1-A670/A800) and Mango index 2 = (A670-A550)/A800 were assessed. Tomato fruit maturity was best indexed using the Tomato index and IAD index, mango maturation by Mango index 1 and 2, and banana ripening by IAD index and red edge.