Determination of amino acid content and its enantiomeric composition in honey samples from Mendoza, Argentina

Abstract

The amino acid (AA) content in honeys from Mendoza (Argentina) was determined by high-performance liquid chromatography and the relative quantities of D- and L-AAs were determined by chiral gas chromatography coupled to mass spectrometry. The results showed that proline was the most abundant AA in all analyzed samples, followed by phenylalanine. Based on the AA content, different chemometric tools were assessed for provenance differentiation. The unsupervised chemometric methods, however, could not differentiate unquestionably the geographical origin of honey based only on their AA content. Enantiomeric ratio demonstrated that D-proline amount was lower than D-phenylalanine levels in practically all honey samples. In addition, D-enantiomers of alanine, valine, glutamic acid, leucine, and isoleucine were found in most samples. The study demonstrated that certain D-AAs can occur naturally in this foodstuff, probably, as a consequence of the Maillard reaction, which is not dependent on microorganism actions. Novelty impact statement: The amino acid content in honey samples from Mendoza was determined by high-performance liquid chromatography. Proline and phenylalanine were the more abundant amino acid. Amino acid enantiomeric ratio was assessed by chiral gas chromatography coupled to mass spectrometry. D-amino acids can occur naturally in the honey samples from Mendoza (Argentina). Chemometric tools were applied to discriminate samples from the geographical origin.