Carbon isotope ratio (13C/12C) of pine honey and detection of HFCS adulteration

• Pine honey is a valuable food which is limitedly produced.
• Pine honey is commonly adulterated using sugar.
• Carbon isotope ratio is one of the most effective criteria to detect sugar adulteration.
• The C isotope ratio of pine honey is reported for the first time with this study.
• The results showed that C4 based sugar addition can be detected by the method explained in the study.

Carbon isotope ratio (13C/12C = δ13C) of 100 pine honey samples collected from 9 different localities by Mugla region (Turkey) in years 2006, 2007 and 2008 were investigated. The δ13Cprotein value of honey samples ranged between −23.7 and −26.6‰, while the δ13Choney value varied between −22.7 and −27‰. For 90% of the samples, the difference in the C isotope ratio of protein and honey fraction (δ13Cpro–δ13Chon) was −1.0‰ and/or higher. Therefore, it can be said that the generally anticipated minimum value of C isotope difference (−1.0‰) for honey is also valid for pine honey. On the other hand, C4 sugar value (%), which was calculated from the δ13Cpro–δ13Chon difference, was found to be linearly correlated with the amount of adulterant (HFCS) in pine honey. These results indicate that C4 sugar value is a powerful criteria for detecting HFCS adulteration in pine honey.The δ13Choney and δ13Cprotein–δ13Choney values of the samples did not show any significant differences in terms of both year and locality (P > 0.05), while the δ13Cprotein values showed significant differences due to year (P < 0.05) but not due to locality (P > 0.05).