Authentication analysis of milkfish fish oil using the combination of FTIR spectroscopy and chemometrics

Milkfish (Chanos chanos) is one of the highest-produced fish in Indonesia. Milkfish fish oil (MFO), extracted from milkfish, contains essential fatty acids and has a high price in the market, therefore MFO can be a target of adulteration. The objective of this study was to perform an authentication analysis of MFO from palm oil using FTIR spectroscopy and chemometrics. MFO was extracted from the head and flesh of milkfish and the obtained MFO was mixed with palm oil (PO) in binary mixtures to get the adulteration model of MFO with PO. All samples were scanned using ATR-FTIR at wavenumbers of 4000-650 cm-1 . Classification between authentic MFO and adulterated MFO with PO was carried out using discriminant analysis. The quantitative analysis of MFO adulterated with PO was carried out with PLSR (Partial Least Square regression) using first derivative spectra with wavenumbers of 3100-670 cm-1 . The R2 values for the correlation between the actual and predicted values in the calibration and validation of MFO were 0.9999 and 0.9994 (MFO extracted from the head) and 0.9997 and 0.9992 (MFO extracted from flesh), respectively. In addition, RMSE (root mean square errors) values of the calibration and prediction of milkfish head oil were 0.0032% and 0.0106%, while MFO extracted from the flesh was 0.0080% and 0.0123%. It can be concluded that FTIR spectroscopy combined with PLSR could be reliable for the prediction of MFO in a binary mixture with palm oil.