Colloidal stability and chemical reactivity of complex colloids containing Fe3

•We prepare three systems of colloidal particles for use as food fortificants.•The particles contain essential minerals such as ironIII, magnesium and calcium.•The reactivity of the contained iron is analysed using spectrophotometry.•Incorporating a second mineral reduces the reactivity of the conta...

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Bibliographic Details
Published inFood chemistry Vol. 155; pp. 161 - 166
Main Authors van Leeuwen, Y.M., Velikov, K.P., Kegel, W.K.
Format Journal Article
LanguageEnglish
Published Kidlington Elsevier Ltd 15.07.2014
Elsevier
Subjects
Biological and medical sciences
Colloidal salt
Essential minerals
Food toxicology
Medical sciences
Micronutrients
Reactivity
Toxicology
Essential minerals
Micronutrients
Reactivity
Colloidal salt
Micronutrient
Trace element
Salt
Chemical stability
Complexes
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Summary:•We prepare three systems of colloidal particles for use as food fortificants.•The particles contain essential minerals such as ironIII, magnesium and calcium.•The reactivity of the contained iron is analysed using spectrophotometry.•Incorporating a second mineral reduces the reactivity of the contained iron.•Coating the particles with protein increases stability and decreases reactivity. The reactivity of iron contained within insoluble colloidal metal-pyrophosphate salts was determined and compared to the reactivity of a soluble iron salt (FeCl3). As a model system for the reactivity of iron in food products, the formation of an iron–polyphenol complex was followed with spectrophotometry. Three types of systems were prepared and their colloidal stability and reactivity studied: Fe3+ pyrophosphate, protein-coated Fe3+ pyrophosphate and mixed-metal pyrophosphates containing Fe3+ and a second cation M. The additional cation used was either monovalent (sodium) or divalent (M2+). It was found that: (i) incorporating iron in a colloidal salt reduced its reactivity compared to free Fe3+ ions; (ii) coating the particles with a layer of hydrophobic protein (zein) increased stability and further decreased the reactivity. Finally, the most surprising result was that (iii) a mixed system containing more Fe3+ than M actually increased the reactivity of the contained iron, while the reverse, a system containing excess M, inhibited the reactivity completely.
ISSN:0308-8146
1873-7072
DOI:10.1016/j.foodchem.2014.01.045