Geographical Origin Characterization of Slovenian Organic Garlic Using Stable Isotope and Elemental Composition Analyses.

Anja Mahne Opatić,David Kocman,Marijan Nečemer,Sonja Lojen

doi:10.17344/acsi.2017.3476

Abstract

In the present research, the applicability of stable isotope (δ13C, δ15N, δ34S, δ18O) and multi-element (P, S, Cl, K, Ca, Zn, Br, Rb, Sr) data for determining the geographical origin of garlic (Allium sativum L.) at the scale of Slovenia was examined. Slovenia is a rather small country (20273 km2) with significant geological and biological diversity. Garlic, valued for its medicinal properties, was collected from Slovenian farms with certified organic production and analyzed by elemental analyzer isotope ratio mass spectrometry combined with energy dispersive X- ray fluorescence spectrometry. Multivariate discriminant analysis (DA) revealed a distinction between four Slovenian macro-regions: the Alpine, Dinaric, Mediterranean and Pannonian. The model was validated through a leave-10%, 20% and 25% out cross validation. The overall success rate of correctly reclassified samples was 77% (on average), indicating that the model and the proposed methodology could be a promising tool for rapid, inexpensive and robust screening to control the provenance of garlic samples.

Highlights

Garlic (Allium sativum L.), a bulb vegetable widely used in global cuisine, is one of the most investigated food products
The lowest δ18O values were measured in garlic samples from the Dinaric region, whilst the highest δ18O values were found in samples from the Mediterranean region
The results show a definite tendency towards their respective Slovenian macro-regions, the slight overlap among some samples is likely due to them having been grown in regions with similar geological and climatic conditions and to the natural variability of the samples

Summary

Introduction

Garlic (Allium sativum L.), a bulb vegetable widely used in global cuisine, is one of the most investigated food products. It contains approximately 65% water, 28% carbohydrates, 2% proteins, 1.2% free amino acids and 1.5% fiber. Proof of provenance has played an increasingly significant role in food safety and quality surveillance programmes. It affects consumers’ rights in accordance with national legislation, international standards and guidelines. One of the important techniques, where the scope of geographical assignment of food products can be remarkably extended, relies on a combination of isotopic and elemen-

Methods

Results

Conclusion