Beef, chicken and lamb fatty acid analysis — a simplified direct bimethylation procedure using freeze-dried material

Abstract

When fractionation of meat lipids is not required, procedures such as saponification can be used to extract total fatty acids, reducing reliance on toxic organic compounds. However, saponification of muscle fatty acids is laborious, and requires extended heating times, and a second methylation step to convert the extracted fatty acids to fatty acid methyl esters prior to gas chromatography. Therefore the development of a more rapid direct methylation procedure would be of merit. The use of freeze-dried material for analysis is common and allows for greater homogenisation of the sample. The present study investigated the potential of using freeze-dried muscle samples and a direct bimethylation to analyse total fatty acids of meat (beef, chicken and lamb) in comparison with a saponification procedure followed by bimethylation. Both methods compared favourably for all major fatty acids measured. There was a minor difference in relation to the C18:1 trans 10 isomer with a greater (P<0.05) recovery with saponification. However, numerically the difference was small and likely as a result of approaching the limits of isomer identification by single column gas chromatography. Differences (P<0.001) between species were found for all fatty acids measured with no interaction effects. The described technique offers a simplified, quick and reliable alternative to saponification to analyse total fatty acids from muscle samples.