(P11-055-23) Wheat Aleurone Provides a Bioavailable Source of Iron for Fortifying Wheat-Based Foods

Objectives: Cereals are important staple foods and are rich in iron. Wholewheat flour contains 3-5 mg iron /100 g. However, most of the iron is removed during the production of white flour. In many countries white flour is fortified to replace the iron lost during processing, however, the forms of iron used for fortification have low bioavailability. Most of the wheat iron is localised to the aleurone layer and in this study, we have tested the hypothesis that addition of wheat aleurone to white flour provides a bioavailable source of iron for fortifying wheat-based foods.

Methods: Bread rolls were produced using white flour fortified with either aleurone flour or elemental iron, added to give a final iron content of 10 mg /100 g bread. Samples were ground in a coffee grinder and subjected to simulated gastric digestion (pepsin (16 mg/ml) in isotonic saline, pH 2.0, 90 minutes). Iron released during digestion was measured using ICP-OES. Digests were mixed 1:1 with MEM culture medium and added to Caco-2 cells. Cellular iron uptake from digests was measured using ICP-MS. Data are mean ± SEM. Statistical analysis was by Student’s t-test.

Results: Iron release following in vitro digestion was greater from aleurone-fortified breads than from bread fortified with elemental iron (+42.8%, P< 0.005). Iron absorption by Caco-2 cells was also significantly higher from breads containing aleurone compared with elemental iron (+104.3% P< 0.02).

Conclusions: White flour is commonly fortified with elemental iron. While elemental iron has good sensory properties for food fortification, it has limited bioavailability. Here we have shown that the iron-rich aleurone fraction of wheat can be added to white flour to provide a bioavailable source of iron. Given that aleurone is rich in several minerals and B-vitamins it may have wider benefits as a functional food ingredient to improve the nutritional quality of wheat foods made from white flour.

Funding Sources: UK Biotechnology and Biological Sciences Research Council