Elemental and stable isotopic study of sweeteners and edible oils: Constraints on food authentication

Elemental concentrations and stable isotopic compositions of 41 sweeteners (syrups, honeys, and sugars) and 43 edible oils were determined to evaluate their potential as parameters for food authentication. The addition of as little as 10% of corn syrup to pure maple syrup can be detected using molar ratios of Na/(Na + K) and Na/(Na + Ca) for maple syrups. The detection of more than 15% adulterant in maple syrup and honey is also possible due to the 13‰ difference in carbon isotopic composition of C3 plants for authentic honeys and maple syrups (25.1 ± 1.1‰) relative to the carbon isotopic composition of C4 plants for corn syrups and cane sugars (−11.4 ± 0.8‰) as major adulterant agents. Nearly constant net oxygen (1.028 ± 0.002) as well as hydrogen (0.974 ± 0.005) isotope fractionation factors between honeys and average local meteoric waters from two areas, Kingston and Costa Rica, suggests that these isotope ratios of honeys are good candidates to authenticate their geographic locations. The net oxygen (1.03 ± 0.001) as well as hydrogen (0.894 ± 0.003) isotope fractionation factors between olive oils and local meteoric waters from different parts of Italy suggests that these isotope ratios are independent of the oil processing method and therefore can be used to trace geographic locations.