Authentication of Indian Honey Based on Carbon Stable Isotope Ratio Analysis—Verification of Indian Regulatory Criteria

The present study was undertaken for the first time in India to generate a database of isotopic signatures of authentic Indian honey to verify the regulatory criteria laid down by the Food Safety and Standards Authority of India (FSSAI). In this study, ninety-eight (98) authentic honey samples from nineteen (19) different botanical sources were collected from five (05) geographical regions of India and analyzed to generate a database of stable carbon isotope ratios (¹³C/¹²C) by Elemental Analyzer/Liquid Chromatography-Isotopic Ratio Mass Spectrometry (EA/LC-IRMS). The samples were analyzed for the parameters <i>δ</i>¹³C_Honey(<i>δ</i>¹³C_H), <i>δ</i>¹³C_Protein(<i>δ</i>¹³C_P), <i>δ</i>¹³C individual sugars, ∆<i>δ</i>¹³C_{Protein-Honey}(<i>δ</i>¹³C_P-H), C4 sugar, ∆<i>δ</i>¹³C_{Fructose-Glucose}(<i>δ</i>¹³C_Fru-Glu), ∆<i>δ</i>¹³C_max, and foreign oligosaccharides (FOs), as per the official methods of analysis of the Association of Official Analytical Chemists (AOAC 998.12) and the FSSAI. The results were evaluated against the published literature and Indian regulatory criteria for authentic honey. The <i>δ</i>¹³C value for honey (<i>δ</i>¹³C_H) ranged from -22.07 to -29.02‱. It was found that 94% of Indian honey samples met the criteria for Δ<i>δ</i>¹³C_P-H (≥-1.0‱), Δ<i>δ</i>¹³C_Fru-Glu (±1.0‱), and C4 sugar content (7% maximum), with negative C4 sugar values treated as 0% as prescribed by the AOAC method. Further, 86% of samples met the FO criteria (maximum 0.7% peak area). Thus, the data of this study provide scientific backing for these four (04) parameters as per the FSSAI regulation. However, the non-compliance of a high number (47%) of authentic honey samples for Δ<i>δ</i>¹³C_max (±2.1‱) compels further systematic investigation with a special focus on bee feeding practices. Further, in the present study, it was found that honey samples with a Δ<i>δ</i>¹³C_P-H greater than +1‱ and a C4 sugar content more negative than -7% also did not comply with the Δ<i>δ</i>¹³C_max criteria. Hence, Δ<i>δ</i>¹³C_P-H values (>+1‱ equivalent to C4 sugar < -7%) could be an indicator of C3 adulteration to some extent.