Detection and evaluation of saccharide adulteration in Italian honey by NMR spectroscopy

The detection of honey adulteration is still an open question, and in these last year's particularly challenging due to the very limited production. This illegal practice is attracting producers worldwide, mostly due to the relevant economic gain available and to the lack of an official analytical method able to detect adulterations, particularly syrups. In the present study the use of both targeted and untargeted NMR spectroscopy have been applied to reveal inulin, corn/malt syrup and invert sugar syrup addition. Untargeted NMR data of pure and artificially adulterated samples in the range of 10-40% were statistical analyzed and OPLS models were used to predict samples spiked with the saccharide adulterants, resulting in very good predictions of the adulteration percentage. Targeted NMR data were concurrently evaluated, allowing to predict the adulteration percentage on the basis of calibration curves. Both these approaches revealed their robust capability in detecting and estimating the percentage of adulteration in the three different botanical origins of Italian honeys, like chestnut, polyfloral and acacia, thus suggesting the potential applicability of this approach to other botanical origins.