Nondestructive determination of pear internal quality indices by visible and near-infrared spectrometry

• Published in: Food science & technology 2008-11, Vol.41 (9), p.1720-1725
• Main Authors: Liu, Yande, Chen, Xingmiao, Ouyang, Aiguo
• Format: Article
• Language: English
• Subjects: analytical methods; Biological and medical sciences; Firmness; food analysis; food composition; Food industries; Fruit and vegetable industries; fruit quality; Fundamental and applied biological sciences. Psychology; mathematical models; near-infrared spectroscopy; Nondestructive measurement; nondestructive methods; Pear fruit; pears; prediction; soluble solids; Soluble solids content; ultraviolet-visible spectroscopy; Visible and near-infrared spectrometry
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2007.10.017

The relationships between the nondestructive visible and near-infrared (Vis-NIR) measurements and the internal quality indices of pear fruit were established, and the potential of Vis-NIR spectrometry technique was investigated for its ability to nondestructively measure soluble solids content (SSC) and firmness of intact pear fruit. Intact pear fruit were measured by diffuse reflectance Vis-NIR in 350–1800 nm range. In this study, calibration models relating Vis-NIR spectra to SSC and firmness were developed based on multi-linear regression (MLR), principal component regression (PCR) and partial least squares regression (PLSR) with respect to the logarithms of the reflectance reciprocal log(1/ R), its first derivative D 1 log(1/ R) and second derivative D 2 log(1/ R). The best combination, based on the robust models and the prediction results, was PLSR method with respect to log(1/ R) at equatorial position of pear fruit. The PLSR models for prediction samples resulted correlation coefficient ( r p) of 0.912 and 0.854, and root mean standard error of prediction (RMSEP) of 0.662°Brix and 1.232 N for SSC and firmness, respectively. The results indicate that Vis-NIR spectrometry technique could provide an accurate, reliable and nondestructive method for assessing the internal quality indices of intact pear fruit.