Non-destructive measurement of pH, soluble solids and firmness of Jonagold apples using NIR-spectroscopy.

摘要

In this paper, the potential of visible and near infrared spectroscopy (380-2000 nm) as a non-destructive measurement technique for measuring quality characteristics of Jonagold apples is evaluated. A relation has been established between the reflectance spectra recorded with bifurcated optical fibre and fruit parameters such as the pH, the soluble solid content, the stiffness factor and other texture parameters such as the E-modulus of the flesh. The data were analysed with multivariate calibration techniques such as principal component analysis, principal component regression and partial least squares analysis. The impact of the data pre-processing on the prediction performance has also been investigated. The models for the pH, the soluble solidcontent and the stiffness factor indicated a good to an excellent prediction performance. It was shown that the pH model has a physique-chemical background. The prediction performance of the models for mechanical texture properties such as the E-modulushowever, was not yet satisfactory.