Authenticity assessment of garlic using a metabolomic approach based on high resolution mass spectrometry

Abstract Depending on conditions in a growing locality and several other factors, marketed garlics ( Allium sativum L.) may largely differ in content of flavour significant compounds and other biologically active components. To enable verification of tradeŕs declarations on the geographic origin, a new analytical, metabolomic fingerprinting, was employed for analysis of 47 samples of garlic with the designated country of origin Czech Republic, Spain and China. Non-target screening of metabolome components occurring in garlic extracts was performed employing following three instrumental platforms based on high resolution mass spectrometry (HRMS): (i) ambient mass spectrometry utilizing direct analysis in real time ionization (DART) ion source coupled to HRMS; (ii) direct infusion (DI) of sample into electrospray ion source (ESI) coupled to HRMS; (iii) high performance liquid chromatography (HPLC) – ESI – HRMS. Statistical models (Orthogonal Partial Least Squares-Discriminant Analysis, OPLS-DA) models were constructed on generated data with the aim to identify the best HRMS technique enabling a reliable differentiation of a country of origin. The best prediction ability, up to 100%, was obtained by processing the data generated by HPLC-HRMS. Alliin, phosphatidylcholine (16:0/18:2), arginine, dehydroalanine, phosphatidylethanolamine (16:0/22:6), L-γ-Glutamyl- S -allyl- l -cysteine and choline glycerolphosphate, were identified as compounds most contributing to a correct classification of the samples.