Authentication of Natural Vanilla Flavorings:  Isotopic Characterization Using Degradation of Vanillin into Guaiacol

Abstract

The isotopic investigation of vanillin has been extended to the new sources of natural precursors of vanillin recently introduced with a view of obtaining natural vanillin by biotechnological processes. To check the consistency of the isotopic composition of vanillin with that of the corresponding aromatic fragment, a selective degradation reaction into guaiacol was carried out. The reaction was shown to proceed without significant isotopic fractionation at the sites of interest, and an optimized procedure was defined from the results of an experimental design involving the quantity of reagent and the temperature and duration of the experiment. Guaiacol, which can be easily obtained in a reasonable time, is an interesting isotopic probe for carbon- and oxygen-isotope ratio mass spectrometry (IRMS) determinations. It provides (13)C information specific to the aromatic fragment and, combined with delta(13)C values measured on vanillin itself, it improves the authentication potential of carbon-IRMS. Thus, the natural status of ferulic acid may be characterized by significant (13)C depletion at the formyl site. Similarly, the oxygen-18 content of guaiacol is a better authentication tool than delta(18)O of vanillin because it does not suffer the drawback of being altered by chemical exchange of the sp(2) oxygen atom with water in industrial or laboratory procedures. Although collaborative studies are still necessary to improve the interlaboratory reproducibility of the delta(18)O parameters, consistent results can be obtained in an intralaboratory context. It is shown in particular that chemical oxidation of ferulic acid is characterized by a relative enrichment of the aromatic moiety of vanillin.

Laboratory-evolved Vanillyl-alcohol Oxidase Produces Natural Vanillin

“…Moreover, vanillin displays antimicrobial and antioxidant properties and is used as a food preservative and for medicinal purposes (10 -15). Natural vanilla flavor from the orchid Vanilla planifolia (16,17) supplies Ͻ1% of the total demand for vanillin. Therefore, because of the increasing interest in natural products, alternative processes are being developed to produce natural vanillin (15, 18 -20).…”

Easy Extraction Method To Evaluate δ13C Vanillin by Liquid Chromatography–Isotopic Ratio Mass Spectrometry in Chocolate Bars and Chocolate Snack Foods

“…Of the chocolate bars and chocolate snack foods in Table 1, the samples 1, 3,7,8,9,10,11, and 12 were declared as "vanilla" on the label. Only samples 3 and 11 gave results that agreed with this declaration.…”

“…7 Site-specific natural isotope fractionation combined with nuclear magnetic resonance (SNIF−NMR) measurements has produced data that define the site-specific abundance of deuterium or carbon-13. 8,9 Several reports have shown that 2 H NMR spectroscopy allows for the determination of the synthetic or natural origin of vanillin as well as providing information about the starting materials. 6,8−12 The determination of stable isotope ratio mass spectrometry of carbon is presently a useful method for discrimination between natural vanillin from vanilla beans and synthetic vanillin or that produced from biotechnological methods.…”

“…9,14,15,17 According to the range reported in the literature, values of δ 13 C greater than −21.5 18 or −21.8 17 for vanillin are used as a criterion of authenticity (vanillin from vanilla beans).…”

Fast single run of vanilla fingerprint markers on microfluidic‐electrochemistry chip for confirmation of common frauds

“…The replacement of VAN with EVA inevitably results in the use of the flavoring in artificial products because the presence of this compound is a unambiguous evidence of their non-natural origin. However, the presence of VAN in vanilla-related samples is not unequivocal proof of their authenticity because adulteration of vanilla extracts with synthetic VAN (lignin-derived) is a major problem in commercial products [18][19][20][21]. As a consequence, the high demands and the high price of authentic vanilla extracts leads to numerous attempts to blend and adulterate samples and their authenticity must be verified by MS or by multianalyte detection in vanilla extract profiles using GC and HPLC [22][23][24][25].…”