Effect of modified Soxhlet (Soxtec) and Folch extraction method selection on the total lipid determination of aged beef.

This study compared the modified Soxhlet (Soxtec) and Folch extraction methods for determining the total lipid or intramuscular fat (IMF) content of aged beef samples. Ageing periods tested were 0, 5, 8, 10 and 12 weeks during which samples were held in vacuo and at ~ 1.0 °C. Prior to solvent extraction, all samples were freeze-dried and ground. The Folch method was found to result in higher IMF values and therefore higher extraction efficiency when compared to the Soxtec. A linear relationship was evident between the two methods that described 80.9% of the variation between IMF values. An interaction between ageing period and extraction method was identified, although ageing period did not independently impact on averaged IMF findings. Based on these observations and reagent toxicity not being a limiting factor, it is recommended that the Folch extraction method be used to determine beef IMF, although it is acknowledged that the Soxtec method IMF results were strongly aligned with those found using the Folch extraction method and tended towards comparability for beef aged < 5 weeks.