Effect of waxy material and measurement position of a sugarcane stalk on the rapid determination of Pol value using a portable near infrared instrument

Abstract

Near infrared spectroscopy can be applied as a rapid and non-destructive method for monitoring sugarcane quality after determining the precision and accuracy of the approach and model to be used for evaluating stems. In this study, near infrared spectroscopy has been applied to breeding management systems and commercial sugar production. Near infrared spectra were collected using a portable near infrared instrument incorporating a wavelength region of 730–1000 nm. To achieve an effective sampling technique, the investigated cane samples included stems with original cane surface and stems with cane wax removed surface. Results revealed that calibrations based on spectra recorded at only 1-position (1-position spectra) of original samples were poor, while calibrations based on stems with wax removed were acceptable for screening with RMSEP values of 1.2%Pol. Also, the 2-position averaged spectra of non-removed wax samples provided fair models, while 4- and 8-position averaged spectra gave good results with R2 of 0.78–0.82, r2 of 0.78–0.82, RMSEP of 1.2%Pol to 1.4%Pol and RPD of 2.1 to 2.4, respectively. The calibration model developed from removed-wax samples at positions 1-, 2-, 4- and 8-averaged spectra rendered effective performances with R2 of 0.73–0.82, r2 of 0.73–0.84, RMSEP of 1.2%Pol to 1.5%Pol and RPD of 2.1 to 2.5. Outcomes were not different in performance, even if the scanned positions and number of scans differed. Hence, the author concluded that 1-position spectra with removed-wax samples were convenient and suitable for the measurement of cane stalk Pol value.