The effect of oxidation on the iodine values of phospholid in milk, butter and washed-cream serum

Abstract

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.

Oxidized phosphatidylcholines from defatted soybean flakes taste bitter

“…The decreased mobility of SPC-B on thin layers may therefore be due to oxidation known to affect the chromatographic behavior of phospholipids. May and McCay (1968), Sessa et al (1974), and also Pont and Holloway (1967) reported decreases in the mobility of oxidized phospholipids on TLC. According to Pont and Holloway, the mobility of both oxidized phos-phatidylcholine and phosphatidylethanolamine compared to the Rf value of sphingomyelin in chloroform-methanol-water (65:25:4).…”