Brewing Time and Lemon Juice as Factors Affecting the Elemental Composition in Commercial Tea Infusions

Tea is one of the most widely consumed beverages worldwide and can contribute to dietary exposure to both essential and potentially toxic elements. This study investigated the effects of brewing time and lemon juice addition on the concentrations and multivariate relationships among selected metals in commercial black tea infusions. Brewing time significantly affected the concentrations of Pb, Cd, Mn, and Al, whereas acidification through lemon juice addition influenced Pb, Cr, Zn, Cu, Mn, and Al. Prolonged brewing increased Mn and Al concentrations but reduced Pb and Cd levels. Lemon juice addition enhanced the concentrations of Al, Mn, Zn, and Cr while decreasing Cu concentration in the infusions. Principal component analysis demonstrated that acidification was the primary factor shaping the elemental profile of tea infusions, exerting a greater influence than brewing time. The strongest responses to both experimental factors were observed for Mn and Al, whose concentrations increased markedly under acidic conditions and with extended brewing time. Despite these changes, the contribution of Ni, Al, Zn, Cu, Pb, Cd, and Cr to dietary intake or exposure remained low across all brewing variants. In contrast, tea infusions represented a substantial source of Mn, providing approximately 30-60% of the adequate intake, depending on preparation conditions. These findings indicate that common brewing practices can significantly modify the elemental composition of black tea infusions, with acidification having a stronger effect than extraction time. Nevertheless, consumption of the investigated teas is unlikely to pose a significant health risk and may contribute beneficially to manganese intake.