Exploratory ATR-FTIR and 1H NMR Characterization of Commercial Coconut Oils Market in Brazil

Coconut oil is a commercially important vegetable oil whose composition is relevant to food quality assessment. This study explored the complementary use of Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy, combined with principal component analysis (PCA), to characterize commercial coconut oils marketed in Brazil. Thirteen commercial samples available during the sampling period were analyzed, alongside an in-house coconut oil reference and comparison oils. The spectral patterns were interpreted in relation to fatty-acid composition, including features associated with unsaturated fatty acids. Most coconut oil samples clustered close to the reference sample, despite different brands, whereas two samples exhibited spectral profiles more similar to palm kernel oil than to the reference coconut oil. These observations describe similarities in the measured spectral profiles and do not establish adulteration. Overall, these findings highlight the complementary potential of 1H NMR and FTIR spectroscopy combined with chemometrics for the exploratory chemical characterization of coconut oils commercially available in Brazil. Further studies involving more reference samples and independent validation are required before authentication performance.