Application of FTIR Spectroscopy and Chemometrics for the Prediction of Radical Scavenging Activities of Fish oils

Patin (Pangasius micronemus), Gabus (Channa striata) and Bandeng (Chanos chanos) are the freshwater fishes that are widely cultivated in Indonesia. Fish oils are believed to have biological activities including antioxidant activities. The objectives of this study were (1) to determine radical scavenging activity (RSA) of fish oils using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radicals, (2) to classify fish oils from different species and extraction methods using chemometrics of principal component analysis (PCA) and cluster analysis (CA) and (3) to predict the antiradical activities of fish oils from different species and extraction methods using FTIR spectroscopy combined with principal component regression (PCR) and partial least square regression (PLSR). The results exhibited that RSA of Patin fish oil extracted from flesh using maceration technique gave the highest RSA. PCA and CA were successfully applied for the classification of fish oils from different species and extraction based on PC1 and PC2 score plots. Based on dendrogram, the fish oils could be classified into 4 groups. The absorbance values of second derivative FTIR spectra at wavenumbers region of 1440 - 1741 cm(-1) provided the highest correlation between actual values of RSA and FTIR predicted values with coefficient of determination (R-2) of 0.9794, root mean square error of calibration (RMSEC) of 0.737 and root mean square error of prediction (RMSEP) of 0.927. From this study, FTIR spectroscopy combined with chemometrics can be used for classification of fish oils and for predicting the antioxidant activities of fish oils from different species and extraction method.