Study of Malus Asiatica Nakai’s firmness during different shelf lives based on visible/near-infrared spectroscopy

The feasibility of applying rapid and non-destructive analysis based on Visible/ Near-Infrared Spectroscopy (VIS/NIR spectrometer) in detecting Malus Asiatica Nakai’s firmness during different shelf lives was discussed in this manuscript. Based on the best preprocessing technique found for each method, calibration models established by Partial Least-Square (PLS), Principal Component Regression (PCR), and Least Squares-Support Vector Machine (LS-SVM) were compared. The optimal models for firmness of Malus Asiatica Nakai were obtained by PLS with SNV as the best pretreatment. On the 1st day of shelf life, the correlation coefficients of prediction (Rp) and the Root-Mean-Square Errors of Prediction (RMSEP) were 0.7999 and 0.7994, respectively. On the 4th day of shelf life, the indexes were 0.7494 and 0.5856. But with the extension of shelf life, weightlessness rate of Malus Asiatica Nakai was reduced, the mealiness phenomenon became serious, quality had dropped sharply, hence the research of Malus Asiatica Nakai became insignificant. Results showed that, the potential of non-destructive measure for predicting accepted fruit parameters enabled the determination of optimum harvest date and fruit quality in different shelf lives.