A Comparison of Fatty Acids Isolated from Muscle Triglycerides of Grain-Fed and Grass-Fed Cattle

The potential health benefits of eating beef raised exclusively on a grass diet is increasingly in the news. It has been suggested that grass-fed beef contains higher concentrations of conjugated linoleic acid (CLA) and omega-3 fatty acids. This laboratory experiment, aimed at an undergraduate biochemistry audience, allows students to investigate these claims by isolating and analyzing the fatty acids from identical cuts of meat—one of grain-fed origin and one from an animal raised on a grass diet. After isolation of intramuscular triglycerides, individual fatty acids are cleaved by saponification and converted to the corresponding methyl esters. Final analysis is carried out using GC-MS.