Performance of new low-cost handheld NIR spectrometers for nondestructive analysis of umbu (Spondias tuberosa Arruda) quality

The objective of this study was to evaluate the analytical performance of two new low-cost handheld NIR spectrometers for the determination of umbu fruit (Spondias tuberosa Arruda) quality. A third handheld spectrometer, representing a proven good performance for fruit quality analysis, was used as reference instrument. Multivariate calibration models were built using Partial Least Squares regression to determine dry matter (DM), soluble solids (SS), flesh firmness (FF) and skin color (SC). No significant statistical difference was found among the analytical performances of all three spectrometers. The average of the relative root mean square error of prediction (RMSEPr) obtained with the three spectrometers were 5.2 +/- 0.9% for DM, 8.4 +/- 1.5% for SS, 27.6 +/- 2.0% for FF and 8.0 +/- 0.6% for SC. According to these results, the new low-cost handheld NIR spectrometers can be used to monitor umbu fruit quality during ripening with suitable accuracy.