Abstract :
[en] The analysis of fatty acids is crucial from different viewpoints, as it can provide valuable insights into the composition of fats for instance for industrial processes or their impact on nutrition and health. Typically, the analysis of fatty acids involves extracting lipids from the matrix and subsequently undergoing a derivatization process to convert fatty acids into fatty acid methyl esters (FAMEs) before gas chromatography (GC) analysis. Often, the methods routinely employed involve the use of toxic agents (typically (BF3) and may require long process time. In these regards, recently a microwave-assisted extraction and derivatization (MAED) method was developed to significantly reduce the sample preparation time, using less toxic solvent (acidic methanol), proving its equivalence with the official AOCS Ce2b-11.
In this work, we extended the comparison to the AOCS Ce2c-11 and to the extraction and derivatization performed in two separate steps, as often performed to also have the data relative to the total fat. In the latter case, the most common BF3 derivatization and the acidic methanol derivatization were also compared on the same extract. All the processes, involving heating, were performed using the support of microwave, except for BF3 derivatization for simplicity reasons.
In more detail, two types of microwave-assisted extractions (solvent extraction and extraction + hydrolysis) were employed. The extracts were then derivatized using: i) BF3 and ii) an acidic solution of methanol. The combination of different extraction and derivatization methods was compared with the two AOCS reference methods, and with the MAED method, for a total of 7 different methods applied to 7 different food samples, such as dairy, meat, and ready-to-eat foods (Figure 1).
The FAMEs were identified and quantified using GC×GC-FID. The different procedures were compared in terms of FAMEs profile and from a greenness viewpoint, using the AGREEPrep metrics.
