a1 Hannah Research Institute, Ayr KA6 5HL, UK
The nature and composition of the saturated oxo fatty acids in Cheddar cheese have been re-evaluated following isolation by moern chromatographic procedures, including low-pressure column chromatography and HPLC (adsorption and silver ion modes). The oxo fatty acids were identified and quantified (for the first time) by gas chromatography–mass spectrometry in the form of the methyl ester derivatives and many of the structures were confirmed similarly by preparing picolinyl ester derivatives. Thirty-six saturated oxo fatty acids were identified, ranging in chain length from 9 to 22 with an oxo group on carbons 4–17 (except for 12), of which twenty-one had been identified in a previous study and fifteen were new. Fifteen fatty acids tentatively identified by others did not in fact appear to be present.
(Received April 15 1991)
(Accepted July 10 1991)