Abstract. Starch and soluble solid content in papaya are an important parameter for measuringthe maturity of fruit after harvesting. In this work, the application of near infrared (NIR) spectroscopy in measuring starch and soluble solid content in papaya wereevaluated. Samples of papaya were harvested at 135, 131, 128, 121 and 114 days after anthesis. NIRFlex N-500 (Büchi Labortechnik AG, Flawil, Switzerland)with spectra range of 1000–2400 nm was used as spectra acquisition of papaya in reflection mode. After randomly dividing 120 spectra into calibration set and 60 spectra independent prediction set, spectra in the calibration set were subjected to a partial least square (PLS) method with preprocessing of first derivative Savitzky-Golay 9 points (dg1) and multiplicative scatter correction (msc) to establish calibration model. Validation of calibration models on the independent prediction set indicates the prediction accuracy with coefficient of correlation (R), SEC (standard error of calibration), SEP (standard error of validation set) and coefficient of variance (CV)of 0.90, 0.17%, 0.04% and 10.95 for starch content; 0.90, 0.12% and 0.12%and 4.85% for soluble solid content, respectively.The results indicated that NIR spectroscopy could be used to predict the starch and soluble solid content of papaya rapidly and nondestructively.
Keywords: NIR spectroscopy, starch, soluble solid content, papaya, nondestructive