关键词: 乳；甘油三酯；超临界流体色谱-四极杆飞行时间质谱；蒙古马；双峰驼；山羊

Abstract: The triacylglycerols (TAGs) of milks from domesticated dairy animals especially non-bovine mammals were systematically identified and investigated in this research. A total of 31 raw milk samples of Holstein cows, goats, Mongolian horses and Bactrian camels were collected to identify the composition of TAGs by supercritical fluid chromatography-quadruple time-of-flight mass spectrometry (SFC-Q-TOF-MS), and principal component analysis (PCA) was conducted on the data obtained. A total of 145 TAGs were identified from these samples, with molecular mass ranging from 470 to 888, 24–54 total acyl carbons, and 0–9 double bonds. The TAGs were composed of 14 fatty acids (FAs) with 4–20 carbons and 0–3 double bonds. The number of TAGs identified from cow, goat, horse and camel milk was 60, 66, 74 and 44 respectively. The contents of unsaturated TAGs in horse, camel, cow and goat milk were 82.2%, 61.1%, 51.7% and 43.8% respectively. In horse milk, the content of TAGs composed of linolenic acid (Ln) were as high as 45.43%. Fatty acid composition of TAGs in camel milk was the simplest, containing at least one of myristic acid (M), palmitic acid (P), stearic acid (S) and oleic acid (O). The relative content of O-P-O was the highest in Bactrian camel milk fat (5.04%), but lowest in goat milk fat (only 1.8%). The major TAGs of goat milk were composed of saturated fatty acids. Base peak ion chromatograms of the four milks were obviously different from each other. PCA indicated that the four milks were clearly separated, and the distance of clustering was consistent with the taxonomy of species, implying that the TAGs can be applied in modeling for discriminating among milks from different species.

Key words: milk; triacylglycerol; supercritical fluid chromatography-quadruple time-of-flight mass spectrometry; Mongolian horse; Bactrian camel; goat