Redefining oxidative status analysis: combination of near-infrared spectroscopy and DFT for animal fats and oils

This study aims to investigate the oxidative status of six different animal oils and fats, while also comparing experimental results with theoretical findings obtained through density functional theory (DFT) calculations integrated with Fourier-transform near-infrared (FT-NIR) spectral data. The TOTOX and INTOX values of fish oil, tallow, butter, ghee, sheep fat, and poultry fat were evaluated. The fatty acid profiles of these samples were examined using gas chromatography. Additionally, FT-NIR spectra of the lipids were collected. Both experimental and theoretical findings confirmed that short- and medium-chain saturated fatty acids, particularly C4:0 and C8:0, contributed positively to oxidative stability by limiting oxidative reactions. Conversely, long-chain unsaturated fatty acids such as C18:3n3, C20:5n3, and C22:6n3 exhibited higher reactivity and lower stability. Accordingly, the lower oxidation levels observed in ghee and butter compared to fish oil were in strong agreement with the theoretical predictions on fatty acid stability. This study extends previous studies by combining FT-NIR spectroscopy with DFT calculations for the comparative evaluation of animal fats.