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- Hilty, F. M., et al.
(författare)
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Development and optimization of iron- and zinc-containing nanostructured powders for nutritional applications
- 2009
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:47
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Tidskriftsartikel (refereegranskat)abstract
- Reducing the size of low-solubility iron (Fe)-containing compounds to nanoscale has the potential to improve their bioavailability. Because Fe and zinc (Zn) deficiencies often coexist in populations, combined Fe/Zn-containing nanostructured compounds may be useful for nutritional applications. Such compounds are developed here and their solubility in dilute acid, a reliable indicator of iron bioavailability in humans, and sensory qualities in sensitive food matrices are investigated. Phosphates and oxides of Fe and atomically mixed Fe/Zn-containing (primarily ZnFe(2)O(4))nanostructured powders were produced by flame spray pyrolysis (FSP). Chemical composition and surface area were systematically controlled by varying precursor concentration and feed rate during powder synthesis to increase solubility to the level of ferrous sulfate at maximum Fe and Zn content. Solubility of the nanostructured compounds was dependent on their particle size and crystallinity. The new nanostructured powders produced minimal color changes when added to dairy products containing chocolate or fruit compared to the changes produced when ferrous sulfate or ferrous fumarate were added to these foods. Flame-made Fe- and Fe/Zn-containing nanostructured powders have solubilities comparable to ferrous and Zn sulfate but may produce fewer color changes when added to difficult-to-fortify foods. Thus, these powders are promising for food fortification and other nutritional applications.
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| 2. |
- Hilty, Florentine M., et al.
(författare)
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Incorporation of Mg and Ca into Nanostructured Fe2O3 Improves Fe Solubility in Dilute Acid and Sensory Characteristics in Foods
- 2011
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 76:1, s. N2-N10
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Tidskriftsartikel (refereegranskat)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.
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| 5. |
- Teleki, A, et al.
(författare)
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Flame-coating of titania particles with silica
- 2005
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Ingår i: Journal of Materials Research. - Swiss Fed Inst Technol, Particle Technol Lab, Inst Proc Engn, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland. Swiss Fed Inst Technol, Dept Chem & Appl Biosci, Inorgan Chem Lab, CH-8093 Zurich, Switzerland.. - 0884-2914 .- 2044-5326. ; 20:5, s. 1336-1347
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Tidskriftsartikel (refereegranskat)abstract
- Silica/titania composite particles were prepared by co-oxidation of titanium-tetra-isopropoxide and hexamethyldisiloxane in a co-flow diffusion flame reactor. The influence of precursor composition on product powder characteristics was studied by x-ray diffraction, nitrogen adsorption, electron microscopy, elemental mapping, and energy-dispersive x-ray analysis. The flame temperature was measured by Fourier transform infrared spectroscopy. The evolution of composite particle morphology from ramified agglomerates to spot- or fully coated particles was investigated by thermophoretic sampling and transmission/scanning electron microscopy. At 40-60 wt% TiO2, particles with segregated regions of silica and titania were formed, while at 80 wt% TiO2 rough silica coatings were obtained. Rapid flame-quenching with a critical flow nozzle at 5 cm above the burner nearly halved the product particle size, changed its crystallinity from pure anatase to mostly rutile and resulted in smooth silica coatings on particles containing 80 wt% TiO2.
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