Determination of high fructose corn syrup concentration in Uruguayan honey by 13C analyses

• We determined honey adulteration with sugar-C4 in Uruguay.
• With this purpose, the 13C signature of honey and its protein was analyzed.
• The international and a local rejection criterions were used.
• In this set of samples the percentage of adulteration was 5.8 and 7.8% respectively.
• The second criterion was more exigent due to the local ecosystem homogeneity.

The methodology of internal standard which relies on the difference between the isotopic composition in terms of δ13C of honey and its proteins, has been extensively used in many countries to assess honey adulteration with high fructose corn syrup (HFCS) or other C4-adulterants, but there have been no reports of such studies in Uruguay. To obtain this information, 51 honey samples were collected from different outlets in two Uruguayan regions. The δ13C composition of honey varied between −26.89 and −23.72‰, while that of its proteins ranged between −26.49 and −24.61‰. When the international value of −1.0‰ was used as the maximum accepted difference between the isotopic values of proteins and honeys, it was determined that 5.9% of samples were adulterated with HFCS, but when this limit was replaced by the locally determined threshold of 0.80‰, the proportion of adulterated samples increased to 7.8%. Both values, however, were lower than most of those reported internationally, which suggest that honey fraud is not widespread in Uruguay.