Non-destructive follow-up of ‘Jintao’ kiwifruit ripening through VIS-NIR spectroscopy – individual vs. average calibration model’s predictions

Visible/near infrared spectroscopy (Vis-NIRS) was used to monitor the yellow-fleshed kiwifruit (Actinidia chinensis Planch ‘Jintao’) ripening on two selected orchards along 13 weeks, from pre-harvest late harvest. Calibration models for several Internal Quality Attibutes (IQA) were built spectral data of 375 individual kiwifruit. The analyzed IQA L*, a* and b* CIELAB color space, hue angle, chroma, firmness, dry matter (DM), soluble solids content (SSC), juice pH titratable acidity (TA). Different pre-processing methods tested construction PLS calibration models. SSC Hue best performing with a correlation coefficient 0.81 0.88, root mean square error prediction (RMSEP) 1.27% 1.95?, respectively. interpretation in terms known absorption bands impact signal noise ratio (SNR) them is discussed. perform average predictions orchard subareas, each day experiment. These compared IQA’s reference values same subareas days. model’s metrics improved significantly through averaging procedure, RMSEP = 0.26–0.36% R2 0.99 SSC; 0.42? – 0.56? ? 1 Hue. Since management done essentially averages not values, this result reinforces applicability NIR technology follow-up fruit tree.