Measurement of Soluble Solids Content of Intact Pear and Pear Juice using Vis/NIR Spectroscopy Technique

Abstract

The objective of this research was to measure soluble solids content of intact pear and pear juice (Pomaceae pyrifolia Nakai cv. Cuiguan) using Vis/NIR spectroscopy technique. In this study, 235 pear samples which were harvested from one orchard of CiXi Zhejiang on three occasions during a 3-week commercial harvesting period were used. The spectra of intact pear and pear juice were collected by a fiber spectrometer of USB4000 with wavelength range of 345~1040 nm. Chemometrics methods such as stepwise multiple linear regression (SMLR) and partial least squares (PLS) were used to develop calibration model. The results show that Vis/NIR spectra is feasible for measuring soluble solids content of intact pear and pear juice, and both obtain acceptable results. The best correlation coefficients (R), root mean square errors of calibration (RMSECs) and root mean square errors of prediction (RMSEPs) for intact pear and pear juice in PLS regression are 0.904, 0.358, 0.472, and 0.922, 0.322, 0.404, respectively. The best SMLR models for intact pear obtain similar results with PLS regression, while the best SMLR models for pear juice obtain inferior results to PLS regression.