Vol. 55, Issue 3, pp. 355-365 (2025)

Abstract

To achieve non-contact quantitative testing of various sugar-like concentrations in sugar-sweetened beverages, we built an infrared spectroscopy testing system for sugar-sweetened beverages, and proposed a multi-characteristic spectral weighting algorithm. The system uses the infrared laser to irradiate sugar-sweetened beverages and analyzes their absorption characteristics in the reflected spectrum. We selected multi-characteristic wavelengths for combined analysis based on the characteristic wavelength distribution of the sugar. In the calibration experiment, it obtained the near-infrared characteristic spectrum distributions of glucose, sucrose, and fructose. During the process of changing sugar concentration from 1.0% to 5.0%, the absorbance increased from 0.045 to 0.215. The linearity of its growth rate is 0.997. The test results for comparing algorithms show that in condition 1, the SCW method’s test mean is very different from the real value. It cannot tell the difference between different types of sugar concentrations in mixed sugar solutions. The test mean of the DWD method and this algorithm are 19.1% and 6.3%, respectively. In condition 2, the test mean values of SCW method, DWD method, and this algorithm are 15.0%, 7.6%, and 4.2%, respectively. It verifies that this algorithm has better accuracy in sugar concentration inversion.