Detection of Sucrose Content of Sugar Beet by Visible/Near Infrared Spectroscopy

Abstract

<abstract> <bold>Abstract. </bold>Sucrose content is the most important quality parameter in the production and processing of sugar beet. This paper reports on the application of visible/near-infrared (Vis-NIR) spectroscopy for measurement of the sucrose content of sugar beet. Two portable spectrometers, covering the spectral regions of 400-1,100 nm and 900-1,600 nm, respectively, were used to acquire spectra in interactance mode from both intact beets and beet slices. The sucrose content of beets was measured using high performance liquid chromatography (HPLC). Calibration models for each spectrometer were developed using partial least squares (PLS) to predict the sucrose content of beets. For the spectrometer covering the visible and shortwave near-infrared (Vis-SWNIR) region of 400-1,100 nm, the correlations (R_p) were 0.81 and 0.86, and the standard error of prediction (SEP) were 0.91 and 0.78, for the intact beets and beet slices, respectively. For the NIR spectrometer with the spectral region of 900-1,600 nm, R_p = 0.72 and 0. 88 and SEP = 1.02 and 0.69 for the intact beets and beet slices, respectively. These results showed that the portable spectrometers operated in interactance mode can be used to predict sucrose content for beet slices. This research also identified several important wavelengths that had relatively strong correlation with the sucrose content, for both Vis-SWNIR and NIR measurement, indicating the possibility of using selected wavelengths or bands for predicting the sucrose content of beets.