Presence of C4 Sugars in Honey Samples Detected by The Carbon Isotope Ratio Measured by IRMS

Gilberto J.Padovan, Luciana P.Rodrigues, Izabel A.Leme, David De Jong and J€lio S.Marchini

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Honey adulteration, carbon isotope ratio, exogenous sugars.


Honey is occasionally adulterated with low-cost sugars. The 13C/12C ratio is –22 to –33δ‰, in honey from C3 plants, –10 to –20δ‰ in honey from C4 plants, and –11 to –13.5δ‰ in honey from Crassulacean Acid Metabolism plants. When C4 sugar is added to pure honey, the 13C/12C ratio will be altered, whereas it corresponding 13C/12C ratio protein extract will remains constant. The difference accepts in 13C/12C results between honey and its associated protein extract is -1δ‰ deviation, which provides the international benchmark of 7% of C4 sugar added. This is the international tolerated limit established to consider the honey pure or not. In the present study, 30 imported honey samples were analyzed by ISCIRA mass spectrometry. Twelve of them came from country A, 10 from B, 4 from C, and 4 from D. Six of the samples from country A (50%) and 4 of the samples from country B (40%), were adulterated, whereas none of the samples from countries C and D were adulterated. We also analyzed exogenous sugars, (cane sugar, and corn sugar) and the mean of ten replicates was –11.6 and –10.5δ‰ deviation respectively; as well the two pure honey and the pure honey were proposal adulterated with exogenous sugars, by serial dilution as: 0; 0.5; 1; 2; 5; 10; 15; 20; 50 and 70%.