Multiple stable isotopes characterization as a tool for determination of the geographical origin of honey in Northern China

Mislabeling of the geographical origin of honey poses a serious concern, particularly for honey certified with Protected Geographical Indication (PGI). In this study, multiple stable isotopes (C, N, H and O) of bulk honey, honey protein and honey monosaccharides were employed to discriminate among 83 honey samples from six regions in northern China, using isotope ratio mass spectrometry (IRMS). Significant correlations were identified between the stable isotope signatures of specific environmental variables of their production regions. The hydrogen isotopic signature of hexamethylenetetramine (HMT), derived from monosaccharides, was the primary factor enabling sample differentiation. Orthogonal partial least squares-discriminant analysis (OPLS-DA) achieved an average classification accuracy of 92.1 % and 85.7 % for the training set and prediction set, respectively. This study offered an effective tool of geographical classification for the control of fraudulent geographical labeling of honey traded in markets.