Seasonal variations in fatty acid composition of New Zealand butterfat

Abstract

14-METHYLHEXADECANOIC ACID IN MUTTON FAT 207 37.5°. In the sample of extemal tissue fat analysed, (+)-14-methylhexadecanoic acid constitutes not less than 0-2 % of the total fatty acids. Examination ofother fractions from mutton fat is in progress, and the evidence already accumulated suggests that appreciable quantities of branched-chain acids are present. The work now reported establishes that certain branched-chain acids isolated from wool grease (Weitkamp, 1945) and presumably secreted by the sebaceous glands of the sheep are also present in the extemal tissue fat, and possibly in the other fatty tissues of this animal. SUMMARY (+)-14-Methylhexadecanoic acid has been shown to occur as a minor constituent of mutton fat. We wish to acknowledge the assistance given in this work by Mr M. Fieldes, Soil Bureau, Department of Scientific and Industrial Research, Wellington, who kindly carried out all X-ray measurements. To Mr M. S. Carrie, Chemist to The Hawkes Bay Farmers Freezing Company Ltd., and to the management of that Company, we are indebted for arranging supplies of suitable material for this investigation.

The variation throughout a year in the fatty acid composition of milk fat from 2 dairy herds

“…Again, in contrast to the findings obtained in the Northern Hemisphere, there is a rise in iodine number of milk fat in late summer and early winter accompanied by a depressed Reichert-Meissl value. These observations, which are typical of undernutrition and consistent with mobilization of body fat (Smith & Dastur, 1938), have been considered as reflecting the extent to which milking cows draw on body reserves of fat when pasture is of poor nutritional quality (Hansen & Shorland, 1952;McDowall, 1962).…”

Relationship between triglyceride structure and softening point of milk fat

“…This has led to a number of studies on the melting characteristics of milk fat. Hansen & Shorland (1952), Parodi & Dunstan (1971), Norris, Gray & Dolby (1973) and Steen & Andersen (1974) studied the relationship between fatty acid composition and softening point (SP). The absence of adequate correlation between fatty acid composition and SP in the above studies has been attributed to variation in the stereospecific distribution of fatty acids in the triglyceride molecules.…”

564. The properties of New Zealand butters and butterfats: IV. Refractive index and density of the butterfat

“…Hansen & Shorland(i7), working on New Zealand butterfat, have also pointed out the close relationship that exists between saponification value and Reichert value which itself is correlated with the content of C 4 -C 12 saturated acids (17). Increases in the molecular weight of the fatty acids comprising the mixed glycerides of butterfat obviously will be reflected in decreasing saponification values and also in decreasing densities if the general rule for fats and oils applies (18).…”

“…It is also an accepted rule that the specific gravity varies with the iodine value; and a similar variation for butterfat has been assumed, from theoretical considerations, by Dutch workers (19). In New Zealand butterfat, however, increases in the content of C 4 -C 12 saturated acids are reflected in compensating decreases in the content of C 18 unsaturated acids but in slight changes only in the quantity of palmitic acid (17). Changes in both the saponification values and the density will therefore be governed almost entirely by variations in the content of the lower saturated fatty acids.…”