Authentication analysis of snakehead fish oil using combination of ftir spectra and chemometrics

The price of snakehead (Gabus) fish oil (GFO) in Indonesian markets is 10-15 times of common vegetable oils, therefore GFO is subject to adulteration. This study was aimed to develop FTIR spectroscopy in combination with chemometrics for authentication study of GFO. FTIR spectra of all samples were scanned using attenuated total reflectance at regions of 4000-650 cm^-1. The selection of oil adulterants was based on their similarity in terms of FTIR spectra using chemometrics of principal component analysis (PCA). The quantitative analysis of GFO adulterated with other oils was assisted with chemometrics of multivariate calibrations, while the classification between authentic GFO and GFO adulterated with other oils was carried out using discriminant analysis. The results showed that, based on closeness of score plot in the first principle component (PC1) and second principle component (PC2), palm oil (PO) and corn oil (CO) were selected as oil adulterants. The quantitative analysis of GFO in CO and PO was carried out with PLSR using first derivative spectra exploiting absorbance values at wavenumbers of 3200-600 cm^-1. The R² values for the correlation between actual and predicted values in calibration and prediction samples were 0.9917 and 0.9884, respectively. In addition, root mean square errors in calibration (RMSEC) and prediction (RMSEP) were 0.029 and 0.035, respectively. It can be concluded that FTIR spectroscopy combined with PLSR is accurate and precise tools for prediction of GFO in ternary mixtures with CO and PO. © 2020 Elsevier B.V., All rights reserved.