Determination of 2-MIB and rancid-related volatile lipid oxidation products in hybrid catfish (Clarias macrocephalus × Clarias gariepinus) with an automated HS-SPME-GC–MS-QTOF-arrow technique

A headspace solid–phase microextraction (HS-SPME) method coupled with gas chromatography/mass spectrometry with quadrupole time-of-flight (GC/MS-QTOF) was developed for analysis of volatile off-odor compounds, i.e., earthy/musty (2-methylisoborneol, 2-MIB) and rancid (aldehydes and alcohols), from farmed hybrid catfish (Clarias macrocephalus × Clarias gariepinus). The most efficient extraction of targeted volatiles was provided by 50 min at 70 °C with a CWR-PDMS fiber and 3 g of fish diluted to 5 mL with 1.5 g NaCl (30 % saturated NaCl). The maximum time-delay before extraction was 8 h to avoid spoilage and lipid oxidation during analysis. The final method showed good linearity, intraday repeatability of 5–9 %, interday reproducibility of 5–12 % and recoveries of 94–112 %. The implementation part proved that the developed method gave accurate quantitative results for oxidation-derived volatiles, several with high correlation to thiobarbituric acid reactive substances (TBARS). Altogether, our study provided an effective SPME-GC–MS method for the extraction and analysis of important off-odor compounds in catfish mince.