Free fatty acid profiling of Greek yogurt by liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis

• Rapid LC-HRMS method for the simultaneous determination of 63 free fatty acids (common FAs, SHFAs and SOFAs) in yogurt samples in a 10-min run. • Application in 26 cow and 7 sheep yogurt samples from the Greek market. • Detailed study of SHFA and SOFA levels in yogurt for the first time. • Different concentrations of 6 common FAs and 5 oxidized FAs allowed the discrimination between cow and sheep yogurt samples by PCA. Yogurt is a fermented dairy product of high nutritional value, very popular in many parts of the world. Free fatty acids (FFAs), which are formed during fermentation, may cause changes in organoleptic properties of yogurt, and thus, the determination of FFAs is of importance. We present a liquid chromatography–high resolution mass spectrometry (LC-HRMS) method, which allows the simultaneous determination of a large set of common and uncommon FFAs in yogurt samples, avoiding any derivatization step. Twenty-five common saturated and unsaturated FAs, together with 21 saturated hydroxy fatty acids (SHFAs) and 17 oxo fatty acids (SOFAs), were analyzed in 26 cow and 7 sheep Greek yogurt samples. A detailed analysis of bioactive SHFAs and SOFAs was carried out in yogurt samples for the first time. Differences at the concentrations of six common FAs and five oxidized FAs between the cow and sheep samples were observed. Based on these FAs, Principal Component Analysis (PCA) allows the discrimination of cow from sheep yogurt samples.