Three methods for the isolation of volatile compounds from oils and fats were compared using small concentrations (approximately 1 ppm) of added C3–12n‐alkan‐2‐ones and C2–10n‐alkan‐1‐ols in commercial butter oil. These were : high vacuum degassing, cold‐finger molecular distillation and reduced pressure steam distillation. Several modifications were incorporated. The highest yields of all compounds were obtained by cold‐finger molecular distillation but difficulties were encountered in subsequent analysis. It was more convenient to recover compounds boiling below 150C by either high vacuum degassing or reduced pressure steam distillation. The latter was more efficient for the higher boiling compounds. Extraction with organic solvents was not required in any of these techniques.
The combination of high vacuum degassing and cold‐finger molecular distillation was found to be the best method of analyzing the complete range of model compounds.
Frozen samples of Antarctic krill (Euphausia superba Dana) were found to contain 71 -4% moisture, and on a dry matter basis 24.6% lipid, 49% protein (N x 6-25), 2.5% chitin, and 9.8% ash. Fatty acids from the crude lipid fraction were made up of 43 -8 % saturated, 32.8 % mono-unsaturated, and 23 * 4 % polyunsaturated types.Krill protein concentrate prepared as a light, fresflowing powder by isopropanol extraction of krill contained 74.3 % crude protein, 15.4 % ash, 6 % chitin and 0.3 % lipid, and was rich in lysine, arginine, tryptophan, and threonine. The protein efficiency ratio of this concentrate was found to be the same as that of casein. The significance of these results in relation to those obtained for other fish protein concentrates is discussed.
SummaryPhospholipid was isolated from milk, butter, and washed-cream serum by solvent extraction followed by simple counter-current distribution and thin-layer chromatography. Iodine values from fresh samples, determined by a micro-Wijs technique, ranged, for the cephalin fraction, from 70 to 86, for the lecithin fraction from 44 to 55, and for the sphingomyelin fraction from 36 to 44. In washed-cream serum, oxidation with copper and ascorbic acid led to reduction in extractable phosphorus, decreased chromatographic mobility of phospholipid and significant falls in the iodine values of the 3 phospholipid fractions. In milk, slight reductions in phospholipid iodine values were observed following copper-catalysed oxidation but they were not consistently significant. Iodine values of butter phospholipids remained unchanged even after gross oxidative quality deterioration.
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