Determination of free cholesterol oxide products in food samples by gas chromatography and accelerated solvent extraction: influence of electron-beam irradiation on cholesterol oxide formation

BACKGROUND The aim of this study was to develop an efficient method for cholesterol oxide product (COP) determination in irradiated and non‐irradiated ready‐to‐eat foods with high water content by gas chromatography–flame ionisation detector after accelerated solvent extraction (ASE), and derivatisation with a silylating reagent. RESULTS The ASE solvent was an 85:15 v/v petroleum ether/chloroform mixture at 40 °C and 1500 psi followed by solid phase extraction. The ASE method was compared with the established lixiviation method, proving an advantageous alternative which reduces analysis time by a factor of 15 and solvent volume by 50%, and minimises the use of chlorinated solvents. COP derivative structures were identified by gas chromatography coupled with mass spectrometry. Analytical characteristics were determined from standards and recoveries were 63–95%, establishing the validity of the method. CONCLUSION The results obtained and their analysis by chemometric techniques established COP formation in food samples after e‐beam irradiation. Increase in COP concentration depended on both irradiation doses and food composition, mainly water and fat content, although linear correlations among variables were not found. © 2016 Society of Chemical Industry