| Abstract
| - Information about the speciation of Pb and Cu in different types of Port wines (white, single-yearand blended aged red, and young red wines) was gathered to estimate their respective bioavailabilities to man. For this purpose, wines were subjected to in vitro simulated gastrointestinaldigestion, and the following properties were studied in the wines and its gastric and intestinaldigests: (1) average conditional stability constant (Kav) of the Cu complexes (by potentiometry), ofthe strongest Pb complexes (those inert to cathodic voltammetry, K‘av), and of the respective ligandconcentrations (CC or CCinert); (2) the distribution of the metal among the different groups ofcompounds of different molecular weights and/or polarities in the different bands separated byreverse phase high-performance liquid chromatography; (3) the total metal concentration presentin the wines and the respective fractions present in the soluble and in the dialyzable fractions ofthe digest (an estimation of the assimilable fraction). The study showed that the complexing affinityfor Pb (expressed by either CCinert or K‘av) of white and very aged red Port wines was lower than forthe remainder of the wines. For Cu, the strength of the ligands in the white wines was lower (<logKav values) than in the other wines, but their concentrations (CC) were higher. For Pb, CCinert wasmuch higher after the digestion than for the untreated wines, whereas the log K‘av values were ∼1order of magnitude lower. These parameters could not be determined for Cu in the gastrointestinaldigests. For all of the studied wines the dialyzable fraction of Pb during the intestinal digestionwas low (10−22% of the total Pb) and the dialyzable fractions of Cu were close to 50% of the totalCu. Keywords: Copper; lead; speciation; Port wine; bioavailability; in vitro digestion
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