Selenium speciation profiles in biofortified sangiovese wine

Biofortification is an agronomic-based strategy, utilized by farmers, to produce selenium (Se)-enriched food products that may help reduce dietary deficiencies of Se occurring throughout susceptible regions of the world. The foliar exposure route application ensures a high efficiency of Se assimilation by the plant since it does not depend on root-to-shoot translocation. In this study we treated grapevines of Sangiovese variety in the pre-flowering period with sodium selenate (100 mg Se L−1). Se content was measured in leaves, fruit at harvest time and in wine respectively in treated and not treated samples with ICP-MS. At harvest, a higher amount of Se in the treated leaves compared to untreated ones was found, 16.0 ± 3.1 mg kg−1 dry weight (dw) against 0.17 ± 0.006 mg kg−1 dw in the untreated ones. The treated grapes had a content of Se of 0.800 ± 0.08 mg kg−1 dw, while that untreated one 0.065 ± 0.025 mg kg−1 dw. Immediately after the malolactic fermentation, the wine obtained from treated and untreated vines had a Se content of 0.620 ± 0.09 mg Se L−1 and 0.024 ± 0.010 mg Se L−1 respectively. In our case the percentage of inorganic Se is 26% of the total Se in the untreated wine, while in Se enriched wine this percentage increase to 47.5% of the total Se. The Se(VI) was the inorganic chemical form more present in enriched wine, probably due to foliar application with selenate. Distributions of Se species suggested being careful to the choice of the enrichment solutions to promote a balanced distribution of different chemical forms, perhaps favouring the accumulation of organic forms.