Soil properties, strontium isotopic signatures and multi‐element profiles to authenticate the origin of vegetables from small‐scale regions: illustration with early potatoes from southern Italy

Abstract

We propose a method for the authentication of the origin of vegetables grown under similar weather conditions, in sites less than 10 km distance from the sea and distributed over a rather small scale area (58651 km 2 ). We studied how the strontium (Sr) isotopic signature and selected elemental concentrations ([Mn], [Cu], [Zn], [Rb], [Sr] and [Cd]) in early potatoes from three neighbouring administrative regions in the south of Italy were related to the geological substrate (alluvial sediments, volcanic substrates and carbonate rocks) and to selected soil chemical properties influencing the bioavailability of elements in soils (pH, cation exchange capacity and total carbonate content). Through multiple-step multivariate statistics (PLS-DA) we could assign 26 potatoes (including two already commercialised samples) to their respective eight sites of production, corresponding to the first two types of geological substrates. The other 12 potatoes from four sites of production had similar characteristics in terms of the geological substrate (third type) and these soil properties could be grouped together. In this case, more discriminative parameters would be required to allow the differentiation between sites.The validation of our models included external prediction tests with data of potatoes harvested the year before and a study on the robustness of the uncertainties of the measurement results. Annual variations between multi-elemental and Sr isotopic fingerprints were observed in potatoes harvested from soils overlying carbonate rocks, stressing the importance of testing long term variations in authentication studies.

Strontium and stable isotope evidence of human mobility strategies across the Last Glacial Maximum in southern Italy

“…This is evident especially during the Early Gravettian, when the Sr isotope ratios of both humans and animals tend to converge towards a common lower Sr ratio, with Equus ferus as the lowest and more likely isotopic end-member. This low ratio within the considered fauna is consistent with animal movements/migrations toward the southern portion of the Apulia region (40). Zooarchaeological and taphonomic evidences of the earliest stages of the Gravettian suggest also a strong reliance on ungulates from open habitats (45).…”

“…In this area, isotopic values higher than modern seawater (~0.7092) are scarcely documented and restricted to specific geological areas that include the volcanic area of Roccamonfina and the Hercynian basement outcrops of Calabria and of the easternmost portion of Sicily ( 87 Sr/ 86 Sr ratios up to ~0.71; 36,37). Instead, low Sr isotope ratios are common among Campanian, Aeolian and Etna volcanoes(38), and along the Salentine coast(39,40).Therefore, the higher and lower Sr isotope ratios endmembers found in the Gravettian teeth could derive from the exploitation of resources as far south as e.g. Calabria.…”

“…Poggio Imperiale, Grotta Scaloria, Passo di Corvo and Masseria Candelaro sites include bone and tooth Sr isotope ratios from (69). Manfredonia site include potatoes data from(40).…”

Life and Death in Neolithic Southeastern Italy: The Strontium Isotopic Evidence

“…0.71043 or higher), this Sr apparently was not mobilised so as to alter the ratios of our bone and tooth samples. It is noteworthy that the Sr signature obtained from the dental enamel of the individuals studied is consistent with data on modern botanical samples from the area of Manfredonia (Zampella et al ., ), with data from Grotta Scaloria, showing the greatest affinity by virtue of a greater range in Sr ratios (see succeeding discussions).…”

“…Sample codes are reported in Table 1. Mean modern values on vegetal species measured by Zampella et al (2011) are indicated. For the animal signatures: Sus sp.…”