Omega-3 fatty acids (FAs) are mainly available as triacylglycerols (TAGs) and ethyl esters (EEs) in fish oil supplements, and it is known that EEs are less bioavailable than TAGs in the human body. This study applied attenuated total reflectance with Fourier transform infrared (ATR-FTIR) and Raman spectroscopies associated with chemometrics to evaluate the supplements’ lipid form. Representative products were first characterized by reference chromatographic methods. Subsequently, principal component analysis (PCA) and partial least square discriminant analysis were performed in the spectral wavenumber ranges 1700–1780 (ATR-FTIR) and 1720–1770 cm^–1 (Raman). TAGs and EEs were clearly distinguished along PC1 by employing both techniques, but a higher explained variance was obtained by ATR-FTIR. The prediction of TAG and EE fish oil samples was also better using ATR-FTIR (R² = 0.99 versus 0.95 for Raman). However, both models correctly classified 100% of the samples, which indicates the suitability of these approaches to be used in quality control laboratories aiming for fish oil lipid form evaluation.

中文翻译：

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ATR-FTIR和拉曼光谱与化学计量学相关的鱼油补充剂脂质形式评价：对比研究

Omega-3脂肪酸（FAs）主要以三酰基甘油（TAGs）和乙基酯（EEs）的形式存在于鱼油补充剂中，众所周知，EEs在人体中的生物利用度低于TAGs。这项研究应用傅立叶变换红外光谱（ATR-FTIR）和化学计量学相关的拉曼光谱法对衰减的全反射率进行了评估，以评估补品的脂质形式。首先通过参考色谱法对代表性产品进行表征。随后，在光谱波数范围1700–1780（ATR-FTIR）和1720–1770 cm ^–1中进行了主成分分析（PCA）和偏最小二乘判别分析（拉曼）通过使用这两种技术，可以在PC1上清楚地区分TAG和EE，但是通过ATR-FTIR获得了更高的解释方差。使用ATR-FTIR对TAG和EE鱼油样品的预测也更好（R ² = 0.99对拉曼的0.95）。但是，两个模型都正确地对100％的样品进行了分类，这表明这些方法适用于旨在评估鱼油脂质形式的质量控制实验室。