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Triglyceride composition of olive oil, cottonseed oil and their mixtures by low temperature crystallization and gas liquid chromatography
Author(s) -
SynouriVrettakou S.,
Komaitis M. E.,
Voudouris E. C.
Publication year - 1984
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02636217
Subject(s) - chemistry , acetone , cottonseed , chromatography , crystallization , composition (language) , linoleic acid , gas chromatography , methanol , cottonseed oil , triglyceride , fatty acid , food science , organic chemistry , biochemistry , cholesterol , philosophy , linguistics
Crystallization and gas liquid chromatography (GLC) have been used to characterize the triglyceride composition of olive and cottonseed oil and their precipitates from acetone or methanol/acetone (10:90, v/v) at −2 C. The precipitate obtained after a 24 hr crystallization of a 5% (w/v) solution of the sample in acetone or methanol/acetone (10:90, v/v) at −2 C was named Precipitate I (P‐I); that isolated after 2 successive crystallizations under identical conditions was named Precipitate II (P‐II). In each case, the ratio of oleic to linoleic acid (O/L) was calculated and proved to be a useful index for detecting adulteration of olive oil with cottonseed oil. In olive oil, the ratio O/L increased from the original sample to its precipitates, whereas in cottonseed oil and the adulterated samples the ratio O/L was lower in the precipitates than in the original sample. For olive oil P‐II, the lowest value of the ratio O/L was 8.4; for the adulterated samples it was 7.6. On the basis of this index, adulteration of olive with cottonseed oil as low as 10% can be detected. Hydrolysis of P‐1 by porcine pancreatic lipase and analysis of the fatty acids of the sn‐2 position showed that the enrichment factor of linoleic acid varied between 1.11–1.30 for olive oil and between 1.55–1.90 for the adulterated samples. Even for adulteration with 5% cottonseed oil, the enrichment factor appears to increase (1.55–1.57) and can be used as a criterion for adulteration.