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Separation of milk fat triacylglycerols by argentation thin‐layer chromatography
Author(s) -
Robinson N. P.,
MacGibbon A. K. H.
Publication year - 1998
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-998-0226-1
Subject(s) - degree of unsaturation , thin layer chromatography , chemistry , chromatography , fatty acid , composition (language) , fatty acid methyl ester , milk fat , organic chemistry , linseed oil , philosophy , linguistics , biodiesel , catalysis
Abstract Argentation thin‐layer chromatography was investigated as a method of obtaining detailed compositional information about milk fat. A modified argentation thin‐layer chromatography procedure, developed to optimize the separation of the complex mixture of total milk fat triacylglycerols, provided nine different groups of triacylglycerols, based on both the degree of unsaturation and the total length of fatty acid groups. Fatty acid methyl ester (FAME) analysis was performed to determine the composition of each band. Separation on the basis of chainlength was most pronounced among the fully saturated triacylglycerol groups, as evidenced by the high level of C 4:0 and C 6:0 in bands 7 and 8, respectively. For the cis ‐monoenoic triacylglycerols, the separation of C 4:0 and C 6:0 was less distinct. The cis,cis dienes and other dienoic, trienoic, or tetraenoic species were principally observed in two bands of retention factor <0.08 on the chromatography plate. Minimal cross‐contamination of bands was observed, with the exception of the lowest of the trisaturate bands, band 7, in which trans ‐monoenes were found to be present. Three samples from different points of the New Zealand dairy season were separated by argentation thin‐layer chromatography, and their FAME distributions were measured. In addition to differences in the masses of band extracts from these samples, levels of C 10:0 and C 12:0 in all bands, and levels of monounsaturates in the dienoic and trienoic bands, were found to differ. These changes were generally consistent with a pattern of decreasing fat hardness over the November to March period of a typical dairy season.