Improved Characterization of the Botanical Origin of Sugar by Carbon 13 SNIF-NMR Applied to Ethanol

Until now no analytical method, not even isotopic ones, had been able to differentiate between sugars coming from C4-metabolism plants (cane, maize, etc.) and some Crassulacean Acid Metabolism plants (e.g. pineapple, agave), because in both cases the isotope distributions of the overall Carbon-13 / Carbon-12 and site-specific Deuterium / Hydrogen isotope ratios are very similar. Following recent advances in the field of quantitative isotopic Carbon-13 NMR measurements, a procedure for the analysis of the positional Carbon-13 / Carbon-12 isotope ratios of ethanol derived from the sugars of pineapples and agave using the Site-Specific Natural isotopic Fractionation ¿ Nuclear Magnetic Resonance (SNIF-NMR) method is presented. It is shown that reproducible results can be obtained when appropriate analytical conditions are used. When applied to pineapple juice, this new method demonstrates a unique ability to detect cane and maize sugar, which are major potential adulterants, with a detection limit in the order of 10% of the total sugars, which provides an efficient mean of controlling the authenticity of juices made from this specific fruit. When applied to tequila products, this new method demonstrates a unique ability to unambiguously differentiate authentic 100% agave tequila, as well as misto tequila (made from at least 51% agave), from products made from a larger proportion of cane or maize sugar, and therefore not complying with the legal definition of tequila.

THOMAS Freddy;  RANDET Célia;  GILBERT Alexis;  SILVESTRE Virginie;  JAMIN Eric;  AKOKA Serge;  REMAUD Gerald;  SEGEBARTH Nicolas;  GUILLOU Claude; 

2010-11-23

AMER CHEMICAL SOC

JRC59905

0021-8561,   

http://pubs.acs.org/doi/full/10.1021/jf102983v,    https://publications.jrc.ec.europa.eu/repository/handle/JRC59905,   

10.1021/jf102983v,