The mixed unsaturated glycerides of liquid fats. Part VI. Low‐temperature crystallisation of rape oil

Abstract

Abstract The mixed glyecrides of rape oil were separated by systematic crystallisation from acetone at low temperatures into three fractions, each less complex in composition than the whole fat. The component acids of each fraction were determined, after preliminary resolution into two groups by low‐temperature crystallisation from acetone or ether, by ester‐fractionation. Spectrographs analysis of alkali‐isomerised acids from selected ester‐fractions showed the presence of more linolenic acid than ha hitherto been reported, and also of small amounts of a docosadienoic acid, C 22 H 10 O 2 . The component acids of the rape oil included myristic o·2%, palmitic 2·2%, stearic 0·4%, arachidic 0·5%, behenic 1·5%, lignoceric 0·8%, with hexadecenoic 0·1%, oleic 15·2%, linoleic i6·0%, linolcnic 7·0%, erucic 53·8%, and docosadicnoic 2·3% (W/W). The component glyceridcs were made up, approximately, of 54% (mol.) containing one unsaturated C 22 and two unsaturated C 18 acyl groups, 28% (mol.) containing two unsaturated C 18 and one unsaturated C 22 . acyl group, and 18% (mol.) containing one group each of saturated and unsaturated C 183 and unsaturated C 22 acids.