Detection of Palm Sugar Adulteration by Fourier Transform Near-Infrared (FT-NIR) and Fourier Transform Infrared (FT-IR) Spectroscopy

In this study, Fourier transform near-infrared (FT-NIR) and infrared (FT-IR) spectroscopy was employed to detect the level of adulteration of Arenga pinnata sugar (AS) with coconut sugar (CS). Various concentrations of CS ranging from 0 to 100% were added to AS, and the absorbance spectra of the resulting mixtures were measured by FT-NIR and FT-IR. The spectra were pre-processed via the normalization, standard normal variate, multiplicative scatter correction, and baseline methods and then analyzed using partial least-squares regression. The best models were obtained by applying the multiplicative scatter correction method to the FT-NIR spectra and the normalization method to the FT-IR spectra. Overall, the FT-IR spectra yielded higher determination coefficients and lower error values compared with the FT-NIR spectra. The results confirm the potential use of FT-IR spectroscopy for detecting CS adulteration in AS.