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

Abstract

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%.