Advancing analytical techniques for detecting adulteration in fish oil with vibrational spectroscopy and gas chromatography

Fish oil is a rich source of omega-3 polyunsaturated fatty acids (PUFAs), particularly EPA and DHA, with significant health benefits. However, rising demand has increased the risk of adulteration, compromising quality and consumer safety. This study compares vibrational spectroscopy (FTIR and NIR) and gas chromatography (GC) for detecting adulteration and authenticating fish oil. GC analysis revealed major fatty acids, including palmitic (12–18%), oleic (3.5–12.5%), EPA (15–21%), and DHA (5–10%), consistent with literature values. Partial least squares regression (PLSR) demonstrated high predictive accuracy, with correlation coefficients of cross-validation (≥ 0.95) and low SECV, confirming that NIR-based fatty acid determinations are comparable to chromatography. SIMCA classification revealed clustering by oil origin, with significant separation in the 4200–4500 cm⁻¹ region, particularly at 4352 cm⁻¹, linked to variations in free fatty acids, unsaturation levels, trans fats, and lipid oxidation. This study demonstrates a rapid, reliable method for authenticating fish oil and quantifying omega-3. The handheld FT-NIR provides precise compositional analysis and can determine fatty acid state and geographical origin, enhancing quality control and regulatory practices in the food industry.