The “Regiokorn“ project has led to a revitalization of cereal cultivation in South Tyrol. When certain guidelines are met, prices can be achieved that are significantly higher than the global market price. However, there is a lack of objective and robust analytical methods to protect against counterfeiting and guarantee regional production of cereals. One promising approach to achieve this goal is the Strontium Isotope Analysis.
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Determination of the origin of cereals from South Tyrol and the neighboring regions of Trentino, East Tyrol, and North Tyrol by means of Strontium Isotope Analysis
The “Regiokorn“ project has led to a revitalization of cereal cultivation in South Tyrol. When certain guidelines are met, prices can be achieved that are significantly higher than the global market price. However, there is a lack of objective and...
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The strontium isotope ratio Strontium is comparable to the chemical element calcium and is present in all soils; strontium has several isotopes (isotopes are atoms with the same number of protons and electrons, but a different number of neutrons)....
The strontium isotope ratio
Strontium is comparable to the chemical element calcium and is present in all soils; strontium has several isotopes (isotopes are atoms with the same number of protons and electrons, but a different number of neutrons). Interestingly, there is a strontium isotope resulting from the radioactive decay of rubidium (87Rb → 87Sr). The older a rock is and the more rubidium it initially contained when first formed, the higher the amount of 87Sr relative to 86Sr (the latter isotope does not form through radioactive decay and its concentration is therefore constant). Strontium is absorbed by plants just like calcium; for this reason, the 87Sr/86Sr ratio of the plants reflects that of the soil. The strontium isotope ratio of the soil depends upon the underlying rock from which the soil arose. Primary rocks like granite and gneiss are usually very old and contain relatively much rubidium; for this reason, they have a high 87Sr/86Sr ratio. Carbonate minerals such as dolomite and limestone contain relatively little rubidium and are younger; for this reason, their 87Sr/86Sr ratio is lower.
Analysis of the origin of the cereals
In the year 2020, cereal and soil samples from a total of 85 fields (rye and spelt) from South Tyrol, East Tyrol, and North Tyrol and the Italian province of Trentino were collected before harvest (see Fig. 1). The strontium isotope ratio was measured using a special high-resolution mass spectrometer. There is a distinct difference between cereals from South Tyrol and cereals from Trentino (Fig. 2). This is because cereal cultivation in South Tyrol takes place mainly in the Pusteria Valley and the Upper Venosta Valley. The soils in these areas have a pronounced primary rock (gneiss) content; this explains their high 87Sr/86Sr ratio. In contrast, in Trentino, limestone and dolomite dominate; for this reason, the isotope ratio is significantly lower here. Between North Tyrol and East Tyrol (Austria), and the other regions, no clear distinction is possible; this is because the soils consist of a mixture of primary rock and calcareous sediments.
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Conclusions and prospects The determination of the origin of foods is of great importance to both consumers and producers. This study shows that the strontium isotope ratio in cereals is dependent upon the geology of the place of growing. For this...
Conclusions and prospects
The determination of the origin of foods is of great importance to both consumers and producers. This study shows that the strontium isotope ratio in cereals is dependent upon the geology of the place of growing. For this reason, the analysis of the 87Sr/86Sr ratio is a promising method for determining the origin of agricultural products.
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