Grapes Enrichment with Zinc for Vinification: Mineral Analysis with Atomic Absorption Spectrophotometry, XRF and Tissue Analysis

: Micronutrient deficiency affects individuals all around the world, being a public health problem. To minimize this problem, several alternatives are being developed, namely agronomic biofortification, to increase the amount of nutrients in food crops. In this context, Zn is one of the most relevant micronutrients for the human body, displaying catalytic, structural and regulatory properties. Considering that Zn deficiency leads to health diseases (namely, neurological disorders, autoimmune, degenerative diseases related to age, Wilson’s disease, cardiovascular problems, and diabetes mellitus), a technical itinerary for biofortification was outlined in a field grapes located in Palmela (Portugal), aiming to optimize Zn contents for the Syrah variety. Biofortification was performed with foliar spraying with zinc oxide (ZnO) and zinc sulfate (ZnSO 4 ) throughout the production cycle (at concentrations of 0%, 30% and 60%—0, 450 and 900 g ha −1 ). Zinc biofortification index increased about 59% and 45%, with OZn60 and SZn60, whereas its deposition in the flesh of the grapes increased 2.41 and 2.37 fold and in the seeds ca. 1.76 and 2.19 fold (in OZn60 and SZn60, respectively). After vinification, wine significant increases of Zn contents were also found (1.92 and 1.77 fold) yet, considering the amount of this nutrient in grapes, it is concluded that vinification must also be optimized.