Abstract: The method of visible and near-infrared diffuse reflection (VIS/NIR) spectroscopy was used to rapidly determine soluble solid content (SSC) of intact Mopan persimmon fruits. In spectral region between 570 nm and 1848 nm, calibration results for the SSC of fruits were compared with different regression techniques, different derivative treatments and different scatter and standard treatments. The results indicated that the modified partial least squares (MPLS) model with the first derivative D1 log(1/R) processing and disscattering treatment provided better prediction performance for the SSC in fruits. The correlation coefficient of cross validation (Rcv), correlation coefficient of prediction (Rp2), root-mean-square error of cross-validation (RMSECV) and root-mean-square error of prediction (RMSEP) were 0.8076, 0.8085, 0.4546 °Brix and 0.4482 °Brix, respectively. These results confirmed that it is feasible to use the established VIS/NIR spectroscopy model for the nondestructive determination of the SSC in Mopan persimmon fruits.

Key words: visible and near infrared diffuse reflection spectroscopy, Mopan persimmon, soluble solid content (SSC), modified partial least squares, first derivative absorption spectrum