Partial Least Square Discriminant Analysis of Mangosteen Pericarp Powder by near Infrared Spectroscopy

Abstract

Partial least square discriminant analysis (PLS-DA) was applied to sort out the difference between mangosteen powder and fake samples measured by near infrared (NIR) spectroscopy. The main feature of the NIR diffuse reflectance spectra of the powder samples are overwhelmed by the baseline change due to the difference in the density and average particle size, making the discrimination difficult. The informative spectral feature was readily elucidated when the NIR spectra were subjected to the second derivative. The PLS-DA of the second derivative spectra revealed a substantial level of difference between the mangosteen powder and fake samples due to the resin and dietary fibre predominantly present in the mangosteen.