Flavor Authenticity Studies by 2H/1H Ratio Determination Using On-line Gas Chromatography Pyrolysis Isotope Ratio Mass Spectrometry

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Abstract
Based on 2H/1H ratio measurements of commercial synthetic and “natural” references, the recently developed on-line gas chromatography pyrolysis isotope ratio mass spectrometry (HRGC-P-IRMS) technique was used to determine the δ2HSMOW values of the flavor compounds decanal, linalool, and linalyl acetate, as well as those of E-2-hexenal and E-2-hexenol in foods and essential oils. In preceding model studies, the influence of sample preparation steps (simultaneous distillation extraction, SDE; solvent extraction, SE; liquid liquid extraction, LLE) on the δ2H values was found to be negligible. For decanal, the typical 2H abundance, with higher content of 2H for synthetic material (δ2HSMOW from −90 to −156‰) and lower 2H content for natural references (δ2HSMOW from −138 to −262‰) was observed. Although the δ2H data recorded for linalool did not allow one to distinguish between synthetic (δ2HSMOW from −207 to −301‰) and natural (δ2HSMOW from −234 to −333‰) materials, the situation was somewhat more encouraging for linalyl acetate; δ2HSMOW values from −199 to −239‰ and from −213 to −333‰ were found for synthetic and natural samples, respectively. E-2-Hexenal and E-2-hexenol showed clear-cut origin-dependent differences in their 2H/1H ratios; that is, δ2HSMOW values from −14 to −109‰ and from −263 to −415‰ as well as from −41 to −131‰ and from −238 to −348‰ were recorded for products from synthetic and natural origins, respectively. Keywords: Flavor authenticity; origin assignment; stable isotope ratio analysis; decanal; E-2-hexenal; E-2-hexenol; linalool; linalyl acetate; HRGC-P-IRMS, 2H/1H ratio