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).