Incorporation of Mg and Ca into Nanostructured Fe2O3 Improves Fe Solubility in Dilute Acid and Sensory Characteristics in Foods

Authors

  • Florentine M. Hilty,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Jesper T.N. Knijnenburg,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Alexandra Teleki,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Frank Krumeich,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Richard F. Hurrell,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Sotiris E. Pratsinis,

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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  • Michael B. Zimmermann

    1. Authors Hilty, Hurrell, and Zimmermann are with ETH Zurich, Human Nutrition Lab., Insti. of Food, Nutrition and Health, Schmelzberstrasse 7, 8092 Zurich, Switzerland. Authors Knijnenburg, Teleki, and Pratsinis are with ETH Zurich, Particle Technology Lab., Dept. of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zurich, Switzerland. Author Krumeich is with ETH Zurich, Electron Microscopy Center (EMEZ), Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland. Direct inquiries to author Zimmermann (E-mail: michael.zimmermann@ilw.agrl.ethz.ch).
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Abstract

Abstract:  Iron deficiency is one of the most common micronutrient deficiencies worldwide. Food fortification can be an effective and sustainable strategy to reduce Fe deficiency but selection of iron fortificants remains a challenge. Water-soluble compounds, for example, FeSO4, usually demonstrate high bioavailability but they often cause unacceptable sensory changes in foods. On the other hand, poorly acid-soluble Fe compounds, for example FePO4, may cause fewer adverse sensory changes in foods but are usually not well bioavailable since they need to be dissolved in the stomach prior to absorption. The solubility and the bioavailability of poorly acid-soluble Fe compounds can be improved by decreasing their primary particle size and thereby increasing their specific surface area. Here, Fe oxide-based nanostructured compounds with added Mg or Ca were produced by scalable flame aerosol technology. The compounds were characterized by nitrogen adsorption, X-ray diffraction, transmission electron microscopy, and Fe solubility in dilute acid. Sensory properties of the Fe-based compounds were tested in 2 highly reactive, polyphenol-rich food matrices: chocolate milk and fruit yoghurt. The Fe solubility of nanostructured Fe2O3 doped with Mg or Ca was higher than that of pure Fe2O3. Since good solubility in dilute acid was obtained despite the inhomogeneity of the powders, inexpensive precursors, for example Fe- and Ca-nitrates, can be used for their manufacture. Adding Mg or Ca lightened powder color, while sensory changes when added to foods were less pronounced than for FeSO4. The combination of high Fe solubility and low reactivity in foods makes these flame-made nanostructured compounds promising for food fortification.

Practical Application:  The nanostructured iron-containing compounds presented here may prove useful for iron fortification of certain foods; they are highly soluble in dilute acid and likely to be well absorbed in the gut but cause less severe color changes than FeSO4 when added to difficult-to-fortify foods.

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