Applicability of visible-near infrared spectroscopy models for determining soluble solid and total acid contents in ‘Nanguo’ pears during storage period

In order to determine the applicability of visible-near infrared spectroscopy models for determining Soluble Solid Content(SSC) and Total Acid(TA) in ‘Nanguo’ pears during storage period, the variance analysis of soluble solid content, total acid contents and Visible-Near Infrared(VIS-NIR) Spectra of ‘Nanguo’ pears during different storage periods were conducted by using Duncan’s new multiple range method. The models with samples stored for six days after harvest at room temperature were established based on partial least squares method and then the prediction performance during different storage periods of ‘Nanguo’ pears were assessed. Results showed that changes of spectra agreed well with those of soluble solid and total acid contents during the storage period of 18 days after harvest at room temperature, whereas the same results were not found in the period of cold storage for 120 days after harvest. The calibrated correlation coefficients of models for determining SSC and TA contents in ‘Nanguo’ pears were higher than 0.83. The predicted correlation coefficients of models both for pears stored at room temperature for 12 days after harvest and for pears in cold storage for 120 days were higher than 0.8. Thus the model was applicable during different storage periods. The results support the application of non-destructive classification for ‘Nanguo’ pears by using visible-near infrared spectroscopy technology.