DETERMINATION OF PROPYLENE-GLYCOL ESTERS OF FATTY-ACIDS IN OILY FOODSBY HPLC

A sensitive method for the determination of propylene glycol esters of fatty acids (PGEs) in foods by HPLC was developed. The PGEs were extr acted from foods and purified by silica gel column chromatography. The isolated PGEs were derivatized with 3,5-dinitrobenzoyl chloride and t he reaction products were dissolved in a mixture of tetrahydrofuran an d acetonitrile (1:1) for HPLC. A portion of this solution was injected onto an Inertsil 5C8 column, and eluted with a mixture of acetonitril e and water (90:10) as the mobile phase. Detection was done with a UV detector set at 230 nm. PGEs in various foods could be selectively det ected without interference. Peaks of PGE having fatty acids of C16:0 a nd C18:0 could be well separated. The recoveries of PGEs added to marg arine, shortening and cake powder at the level of 0.5% or 1.0% were mo re than 93%. The detection limits were 10 mu g/g for total PGE. The pr oposed method for determination of the content and fatty acids composi tion of PGE in foods is suitable for routine work.