Determination of furan and methylfurans in manufactured and commercial ratatouille by headspace gas chromatography coupled to mass spectrometry (HS-GC-MS)

Furan and methylfurans (2-MF, 3-MF and 2,5-DMF) are volatile compounds formed in foods during thermal processing, and there are concerns about their effects on human health. Ratatouille was selected as a case-study food due to its frequent consumption, vegetable-based composition rich in known furan precursors, and the intense thermal treatments typically applied during both domestic and industrial preparation, which may favor furan and methylfuran formation and contribute to dietary exposure. Thus, the present work aimed to develop a method for the simultaneous detection and quantification of furan and methylfurans in samples of homemade and commercially produced ratatouilles. The HS-GC-MS method has been optimized using a Box Behnken experimental design combined with response surface methodology. The optimum conditions were 2.5 g of sample, 30 min incubation time and 60 °C temperature. The method showed good linearity (R² > 0.995), satisfactory recoveries (83-96%) and adequate precision (RSD < 9%), with limits of quantification below 1 ng/g. Furan and methylfurans were detected in all samples, with total concentrations ranging from approximately 3 to 12 μg/kg in pan-cooked ratatouille, 4 to 17 μg/kg in kitchen-robot preparations, and reaching up to 40-55 μg/kg in commercial products. Commercial ratatouilles showed significantly higher concentrations than homemade samples, while kitchen-robot cooking led to higher levels than pan cooking. To our knowledge, this is the first study reporting the simultaneous determination of furan and methylfurans in ratatouille using a validated HS-GC-MS method.