A bread wheat zinc biofortification project - chelating action of food additives in fortified flour and technological development of alternatives to potentiate Zn bioavailability

The selection of new wheat genotypes with a more efficient capacity for Zn accumulation might enhance the human population Zn status. However, a prerequisite for the success of this approach, after the digestive process, is a high efficient Zn absorption through the intestinal epithelium related to its bioavailability. Additionally, mixes for bread and other bakery products and pastries require food additives, namely those acting as sequestrants (sodium diacetate E262ii, acetic and fatty acid esters of glycerol E472a, citric acid E330, tartaric acid E334, magnesium phosphates E343, disodium pyrophosphate E450i, tetrasodium pyrophosphate E450iii, sodium and calcium polyphosphates E452). These additives, which may have several functional uses, can complex metal ions and thus prevent degradation processes (implicating enzymatic and oxidation catalysis by metal ions). Zn absorption may also be affected by other factors like the phytate/Zn molar ratio. The aim of this study is to characterize sequestrants chelating interactions in biofortified Zn flour, produced from wheat genotypes to be selected (after a thorough biochemical and physiological evaluation), and develop alternative technical procedures for food additives (namely non chelating additives) applications, to potentiate human Zn bioavailability. In this context, a model that includes in vitro simulation of gastrointestinal digestion and a human colon carcinoma cell line (Caco-2 cell line), that shows many of the functional and morphological proprieties of mature human enterocytes, will be used to estimate Zn uptake.