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The trisaturated glycerides of bovine milk fat
Author(s) -
Banks William,
Christie William W.,
Clapperton John L.,
Girdler Anne K.
Publication year - 1987
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740390405
Subject(s) - glyceride , triglyceride , chemistry , fatty acid , differential scanning calorimetry , milk fat , composition (language) , organic chemistry , butterfat , melting point , fraction (chemistry) , food science , chromatography , biochemistry , cholesterol , physics , linguistics , philosophy , thermodynamics , linseed oil
Dietary manipulation has been used to produce a range of milk fats differing substantially in fatty acid composition. These fats have then been fractionated by preparing the mercuric acetate adducts to produce the trisaturated glyceride components. The method produced fractions having a very low unsaturated fatty acid content. Calculations suggest that the trisaturated fractions contained appreciably less 4:0 than would be predicted; with a compensating increase in the relative proportion of long‐chain fatty acids. The triglyceride distributions of the parent fats were shown to be markedly bimodal in nature, whereas those of the trisaturated glycerides were unimodal or exhibited fairly small second peaks. Calculations based on the proportion of unsaturated fatty acids present in the milk fat suggest that the strategy of triglyceride synthesis within the bovine mammary gland is not to reduce the production of trisaturated glycerides to a minimum unless only small amounts of unsaturated fatty acid are available. The melting spectra, determined by differential scanning calorimetry, of the parent milk fats were quite different from those of the trisaturated components, with the latter fraction having little material melting below 0°C, but complete melting occurred at slightly higher temperatures. The positions of the major endotherms in the melting spectra of the parent fats on the one hand and the trisaturated fractions on the other indicate that extensive solid solution occurred between the unsaturated and trisaturated components of the parent fat. The heat of melting of the trisaturated glycerides was much greater than that of the parent fats.