Abstract
The determination of free fatty acids (FFAs) in milk is of importance for quality control, legislative purposes, authentication and product development. We present herein a liquid chromatography-high resolution mass spectrometry method for the direct determination of FFAs in milk. The method involves mild sample preparation, avoids time-consuming derivatization and allows the direct quantification of twenty-two FFAs in a 10-min single run. It was validated and applied in thirteen cow milk and seven goat milk samples. Saturated fatty acids C16:0, C18:0 and unsaturated C18:1 (n-9) were found to be the major components of milk FFAs at concentrations of 33.1 ± 8.2 μg/mL, 16.5 ± 5.3 μg/mL and 14.8 ± 3.8 μg/mL, respectively, in cow milk and at concentrations of 22.8 ± 1.8 μg/mL, 12.7 ± 2.8 μg/mL and 13.3 ± 0.3 μg/mL, respectively, in goat milk. Other saturated and unsaturated FFAs were found in significantly lower quantities. Saturated fatty acids C6:0, C8:0 and C10:0 were found in higher quantities in goat milk than in cow milk. The levels of the important (for human health) odd-chain FFAs C15:0 and C17:0 were estimated in cow and goat milk.