Zannella, Carmela (2017) Multi-element profiles and Sr isotopic signatures to authenticate the geographical origin of high-quality food. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Multi-element profiles and Sr isotopic signatures to authenticate the geographical origin of high-quality food.
Date: 11 December 2017
Number of Pages: 97
Institution: Università degli Studi di Napoli Federico II
Department: dep01
Dottorato: phd073
Ciclo di dottorato: 30
Coordinatore del Corso di dottorato:
Date: 11 December 2017
Number of Pages: 97
Uncontrolled Keywords: Fingerprinting, Protected Designation of Origin, Protected Geographical Indication, traceability, strontium isotopic signature, multielement analysis, geographic origin
Settori scientifico-disciplinari del MIUR: Area 07 - Scienze agrarie e veterinarie > AGR/13 - Chimica agraria
Date Deposited: 27 Dec 2017 09:52
Last Modified: 19 Mar 2019 12:01


Nowadays the authentication of food products remains a major issue, especially for those products that receive excellent labels from European Union (i.e. PDO, PGI, TSG) due to their higher price compared to all other non-branded products. The defense of these products helps to prove product authenticity, to combat fraudulent practices and to control adulteration, which are important issues for economic and cultural reasons, as well as contribute to valorize the cultivation territories. The focal point of this thesis was to study the potential of the elemental composition and 87Sr/86Sr isotopic ratio as promising tools for the authentication of agricultural products in relation to their geographic area of cultivation. In this view, four Italian agro-products covered by a Geographic Indication mark were chosen and investigated: “PDO White Asparagus from Bassano del Grappa”, “PDO Green Pistachio from Bronte”, durum wheat flour to make the“PDO Bread from Altamura” and “PGI Red Onion from Tropea”. In addition, the identification of geochemical markers for fish meat directly linked to the ambient water was investigated at the Viris Laboratory at BOKU University (Vienna, Austria) to determine the geographical origin of Austrian fish food. Both soil and plant materials (from 5 farms per agro-product for three replications per farm) were analysed. The soils were characterized for their physical and chemical properties (pH, organic carbon, cationic exchange capacity, total carbonate content, particle-size distribution), content of 41 macro- and micro-elements (included rare earths) and Sr isotopic ratio (87Sr/86Sr) of total and 1M NH4NO3-extractable (i.e. bioavailable) Sr. The plant material was analysed for the total content of 33 elements and the total Sr isotopic ratio. The Sr isotopic ratio was highly promising for agro-product authentication. In particular, the isotopic ratio of Sr found in agro-foods (i.e. Sr uptaken by the plants) was very similar to the isotopic ratio of bioavailable Sr measured in the soils. In contrast, the isotopic ratio of Sr measured in the plants was significantly lower than the isotopic ratio of total Sr measured in the soils. This important outcome has been confirmed in all the analyzed products, except for Tropea Red Onion for which the investigation of isotopic ratio of Sr is still ongoing. The isotopic ratio of Sr found in ‘White asparagus from Bassano del Grappa’ was distinctively different from the Literature values for Sr isotopic ratio of Hungarian and Peruvian asparagus. In contrast, a certain overlap was observed with white asparagus from Austria. A coefficient of variation (CV) was calculated to estimate the degree of similarity among geochemical profiles of soils and plants collected in the same production areas (i.e. variability within production areas). For ‘White asparagus from Bassano del Grappa’, twenty elements were characterized by a CV < 10%. Among these elements Ca, Fe, K, Mg, Mn, Na and P were able to discriminate between asparagus from Bassano del Grappa and asparagus from USA and Spain. For “Green Pistachio from Bronte”, P, Cr, Mg, K, Sc and S were the main discriminating elements (CV < 10%). For “durum wheat flour from Altamura”, Co, Fe, P, Cr, Mg, Ti and K were the elements with a CV < 10%. From a Literature comparison, the Sr content and the Ca/Sr ratio were able to well discriminate “Green Pistachio from Bronte” from pistachios from Iran, Turkey and USA, the main pistachio world producers. The ratio between 87Sr/86Sr vs δ ‰ well discriminate Altamura from China wheat flour. In the case of “Red Onion from Tropea”, the chemical composition of both soils and onions was found highly variable within the production area. None element was characterized by a CV < 10%. Hence, it was not possible to identify a unique geochemical signature for the Tropea Red Onion. This was likely caused by the large geographical scale (both in latitude and altitude) of the production area. The Sr/Ca ratio along with the 87Sr/86Sr isotopic ratio was also applied to determine the geographical provenance of fish meat from different Austrian regions. The development of an analytical approach (including sampling, digestion and analysis) was assessed for the usage of Sr isotopes and multi-element fingerprints as tracer of origin in fish meat. In the next step, the acquainted information will to be linked to the water bodies, which has been tested on a limited number of samples as preliminary study. Further studies based on a larger number of samples of both products covered by Geographical Indication label and similar products with no labels (e.g. agro-products from PDO or PGI areas and similar products outside PDO or PGI areas) might improve the robustness of identified ‘geochemical signatures’ and hence the potential of soil-based indicators for authenticity and geographical provenience traceability.

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