Simplified method for the simultaneous gas chromatographic determination of fatty acid composition and cholesterol in food

A rapid, reliable and accurate gas chromatographic method for the determination of fatty acid composition in food was developed and evaluated. The procedure consists of direct saponification of glycerides and hexane extraction of sterols from the nonsaponifiable matter, followed by acidification of the residual soap and methylation of the free fatty acids. The substantial advantage of this procedure is the possibility of simultaneous determination of the fatty acid composition and the cholesterol of phytosterol content in food. In addition, it eliminates the use of chlorogenic chemicals and minimizes solvent use. This method was compared to a slightly modified standard procedure, involving fat extraction prior to saponification and transmethylation of the fatty acids. For both methods the coefficients of variation for analysed fatty acids (C greater than or equal to 8) ranged from 0.6 to 7.4%. For the majority of fatty acids no significant difference was observed between mean values at a 95% confidence level.