Results of stereospecific analysis of triacylglycerol fraction from donkey, cow, ewe, goat and buffalo milk

In the present research article, donkey milk samples were studied and the results were compared with those obtained from other mammalian species such as cow, ewe, goat and buffalo. Stereospecific analysis of triacylglycerols (TAG) was carried out to determine the intrapositional % fatty acid (FA) compositions and then the interpositional FA distribution in the sn-positions of TAG glycerol backbone. Buffalo milk showed the highest lipid content (9.6%) and donkey milk the lowest (0.3%). The FA distribution among the three sn-positions of the glycerol backbone was non-random; in all the considered milk samples, saturated FA (SFA) were prevalently esterified in sn-3-position, while monounsaturated FA (MUFA) in sn-2-, with some exceptions. Donkey milk represents an important dietary source of essential FA (EFA), about 40 mg/100 g milk; in particular, the linoleic acid is 2.5 times higher than in cow milk (15 mg/100 g versus 6 mg/100 g); moreover, these are esterified in high percentages in sn-2-position, so this milk appears interesting for its potential pharmaceutical and nutritional properties.