An investigation into the determination of the maturity of pawpaws (Caricapapaya) from NIR transmission spectra

The transmission spectra for pawpaws (Carica papaya) in various states of m aturity ranging from immature green through to skin colour break were recor ded over the wavelength range 500-1000 nm using a dual prism spectrometer w ith charge-coupled device detector designed and constructed at the authors' institute. Features observed in the spectra were compared against the visu ally-assessed maturity of the fruit to investigate spectral changes associa ted with the ripening process. An apparent spectral signature of maturity w as noted with a distinct change in the relationship of wavelength of peak t ransmissions at 720 nm to 815 nm between the immature green and ripe fruit, respectively. These results will allow the level of maturity of pawpaws to be classified into at least four categories using only these wavelengths w ith the possibility of using a small portable instrument.