Animal derived lipids often offer more complex fatty acid (FA) profiles when compared to plant based fats and oils.  These FA mixtures attribute to potential flavor generation during food production but also have associated health effects based on carbon chain length, degree of saturation, and presence of chain branching.  Understanding FA composition of neutral and polar lipid species in whey allows for future utilization of whey streams, guiding process design, to make new nutritional ingredients and functional food products.  The advent of ionic liquid (IL) stationary phases for gas chromatography (GC) have led to highly polar phases commercially marketed for rapid, high resolution, and reproducible analysis of fatty acid methyl esters (FAME).  Commonly these IL columns can resolve cis/trans isomers of FA in half the time of other traditional polar stationary phases.  Lipids were extracted from whey powders using a modified Folch method (chloroform-methanol 2:1 v/v) followed by subsequent fractionation by aminopropyl solid phase extraction into neutral and polar lipid fractions.  These lipid fractions were qualitatively analyzed by silica TLC before FAME synthesis by acidic methanolysis.  Lipids were subjected to 2% sulfuric acid in dry methanol overnight in a heated shaking water bath, then extracted with hexane-diethyl ether (1:1 v/v).  Recovered FAME were concentrated under gentle stream of nitrogen before analysis by GC.  Both wax and IL phases (specifically Supelco IL111i) were compared in this study coupled to a flame ionization detector and mass spectrometer.  Neutral and polar lipid fractions differ in fatty acid profiles and relative composition with whey neutral lipids showing more diversity.  In addition, mass spectrometry was used to identify unbranched FA species in powder whey samples including 12-methyltetradecanoic acid, 14-methylpentadecanoic acid and 14-methylhexadecanoic acid. <br/>

Fatty acid profiles of neutral and polar whey lipids determined by ionic liquid stationary phase gas chromatography

2019 Fall National Meeting

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