Comprehensive Authenticity Assessment

The online determination of S Hv-smow values using GC-pyrolysis-IRMS (GC-P-IRMS) was developed recently [55] and has proved to be a powerful tool to define the authenticity of natural compounds [56-61]. However, as fruit fiavour extracts are rather complex, and the sample amount for hydrogen measurement has to be rather high owing to the low abundance of deuterium 

By measuring standard compounds [5-nonanone, linalool, (-)-menthol, lin-alyl acetate, y-decalactone, ( )-a -ionone, 1-octanol, dodecane, methyl decano- 

17 Enantioselective and Isotope Analysis—Key Steps to Flavour Authentication 

Erom natural sources the (R)-enantiomer of ( )-a-ionone is detected with high enantiomeric purity (much more than 99%) hence, the authenticity of ( )-a-ionone is mostly proved via enantio-GC applications [27,65-67]. In the majority of cases synthetic ionones are produced via pseudoionone, prepared by base-catalysed condensation of citral with acetone. After acidic catalysis (using 85% phosphoric acid or concentrated sulphuric acid), this reaction yields racemic ( )-a-ionone and ( )-/l-ionone [68]. 

To point out the relevance of the new coupling technique, Fig. 17.13 shows a precolumn (Fig. 17.13a) and a main column (Fig. 17.13b) chromatogram of a raspberry extract (variety Rucami) measured by MDGC-P-IRMS. The concentrations of ( )-a-ionone and ( )-/l-ionone were adjusted to the linearity range of the isotope ratio mass spectrometer (peak amplitude 4-7 V). 

---

Schmidt H-L, Rossmann A, Werner RA (1998) Flavourings. Wiley-VCH, Weinheim Jung J, Sewenig S, Hener U, Mosandl A (2005) Comprehensive authenticity assessment of lavender oils using multielement/ multicomponent IRMS-analysis and enantioselective MDGC-MS. Eur Food Res Technol 220 232... 

J. Jung, S. Sewenig, U. Hener, A. Mosandl (2005) Comprehensive authenticity assessment of lavander oils using multielement/multicompound IRMS-analysis and enantioselective MDGC-MS. Eur. Food Res. Technol. 220, 232-237... 

Presently, online cGC-IRMS determination of 5 C and 5 H values of flavour compounds are established [107. 118-123] and, further on, 5 0 measurements using online cGC-IRMS procedures will be available. Finally, enantio-MDGC combined with multielement- and multicomponent IRMS methods will open the door to comprehensive authenticity assessment of natural flavour and fragrance compounds in the near future. 

---