Vegetable oils: Are they true? A point of view from ATR-FTIR, 1H NMR, and regiospecific analysis by 13C NMR.

Problems related to oil authenticity make it difficult to obtain the benefits associated with each type of vegetable oil. Fraudulent practices have been revealed by several targeted and nontargeted methods. In this paper, spectroscopic techniques (FT-IR, 1H NMR, and 13C NMR) were applied to determine the chemical profiles of 23 Brazilian commercial vegetable oils obtained from five different high-value aggregated matrices (andiroba, babassu, baru, castor, and sweet almond oils) and investigate their adulteration, by comparison with the corresponding reference samples. Each technique is useful for the particular information it provides: differences in free fatty acids by FT-IR; adulteration with omega-3-enriched oils by 1H NMR, and adulteration of unsaturated-enriched oil with another unsaturated oil without linoleic acid by regiospecific analysis. Our findings highlight the importance of fusion-based methods in providing precise information for use in oil quality authentication.