Maturity prediction of papaya using NIR spectroscopy

The use of NIR spectroscopy was evaluated to predict the maturity of papaya 'IPB 1' non-destructively during harvest time. The maturity was observed from the changes in water content, protein and soluble solid content. Samples of papaya were harvested at 14 days before commercial harvest date and continued for 7, 4 and 0 days later. NIRFlex N-500 (Buchi Labortechnik AG, Flawil, Switzerland) with spectral range of 1000-2400 nm was used as spectral acquisition of papaya in reflection mode. After dividing 124 spectra into calibration set and 62 spectra as independent prediction set, spectra in the calibration set were subjected to a partial least square method with pre-treatment processing to establish calibration model. Validation of calibration models on the independent prediction set indicated that the prediction accuracy with coefficient of determination (R-2), SEC and SEP were 0.85, 0.59 and 0.58 for water content; 0.81, 0.1 and 0,1 for protein content and 0.90, 0.56, 0.76 for soluble solid content. It is concluded that NIR spectroscopy coupled with PLS models can be adopted for predicting maturity of papaya based on the water content, protein and soluble solid content.