Comparison of the Fatty Acid Composition of Peanut Butter by Applying Different Fat Extraction Procedures

The aim of this work was to evaluate the influence of different fat extraction procedures on the fatty acids composition (FAs) of a NIST standard reference material, peanut butter (SRM 2387). Extraction of fat was made with petroleum ether by applying six extraction procedures: Soxhlet automatic with B chi B-811 unit: Soxhlet standard (SS); Soxhlet warm (SW); Hot extraction (HE) and Continuous flow (CF), repeated extraction with solvent (SR) and Soxhlet traditional extraction (ST), by using a Soxhlet extractor. Identification of FAMEs was based on retention time (RT) and the ratio of characteristic ions (m/z) of the reference standards F.A.M.E. Mix C4-C24 and SRM 2377. FAMEs determination was realized by using internal standards (IS) and applying relative response factors (RRFi), and without IS by applying correction factors (Fi). Determination of FAMEs was performed on a GC-MS. Triglyceride of pentadecanoic acid (TAG-IS C15:0) was used as an IS to assess the analyte losses during FAMEs preparation steps, and tricosanoic acid methyl ester (FAME-IS C23:0) was used to evaluate the analyte losses on GC injection. Values of fat content and fatty acids composition determined by the 6 extraction procedures were compared with the NIST certified values of SRM 2387. All 4 procedures of extraction made with B chi unit B-811 were effective in fat extraction and analysis of fatty acids composition compared to standard methods. Between the experimentally determined values and the certified values there were no significant differences.