Contribution of tea (Camellia sinensis L.) to recommended daily intake of Mg, Mn, and Fe: An in vitro bioaccessibility assessment

Abstract

This study outlines the determination of total elemental contents, time-dependent extractabilities, and bioaccessibilities of Mg, Mn, and Fe from nine tea samples, including black, earl grey, and green teas, using inductively coupled plasma mass spectrometry. Leachabilities and bioaccessibilities were evaluated using samples infused for 2, 5, and 10 min, and bioaccessible levels were determined after in vitro enzymatic digestion. Lemon juice, sugar, milk, calcium, and tannic acid were studied as additives, and found to increase or decrease the bioaccessibilities from black tea infusions. Drinking one cup of tea provided 0.16%, 0.01%, and 0.10% of the recommended dietary allowance of Mg for black, earl grey, and green teas infused for 2 min, respectively. The equivalent levels were 11%, 6%, and 7% for Mn, and 0.05%, 0.02%, and 0.02% for Fe in the same samples, respectively. Therefore, Mn was found to be the most bioaccessible element resulting from tea consumption, reaching 17%–24% of the recommended daily allowance in the 10-min infusion. Moreover, lemon juice was found to increase the bioaccessibility of Mn by up to 3.4-fold, even in tea samples infused for 2 min.