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

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.