Reactivity of Fe(III)-containing pyrophosphate salts with phenolics: complexation, oxidation, and surface interaction

Judith Bijlsma; Neshat Moslehi; Krassimir P Velikov; Willem K Kegel; Jean-Paul Vincken; Wouter J C de Bruijn

doi:10.1016/j.foodchem.2022.135156

Reactivity of Fe(III)-containing pyrophosphate salts with phenolics: complexation, oxidation, and surface interaction

Food Chem. 2023 May 1:407:135156. doi: 10.1016/j.foodchem.2022.135156. Epub 2022 Dec 6.

Authors

Judith Bijlsma¹, Neshat Moslehi², Krassimir P Velikov³, Willem K Kegel⁴, Jean-Paul Vincken⁵, Wouter J C de Bruijn⁶

Affiliations

¹ Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands. Electronic address: judith.bijlsma@wur.nl.
² Van 't Hoff Laboratory for Physical and Colloidal Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands. Electronic address: n.moslehi@uu.nl.
³ Unilever Innovation Centre Wageningen, Bronland 14, 6708 WH Wageningen, the Netherlands; Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands; Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands. Electronic address: krassimir.velikov@unilever.com.
⁴ Van 't Hoff Laboratory for Physical and Colloidal Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands. Electronic address: w.k.kegel@uu.nl.
⁵ Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands. Electronic address: jean-paul.vincken@wur.nl.
⁶ Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands. Electronic address: wouter.debruijn@wur.nl.

PMID: 36525808
DOI: 10.1016/j.foodchem.2022.135156

Abstract

Mixed pyrophosphate salts with the general formula Ca_2(1-x)Fe_4x(P₂O₇)_(1+2x) potentially possess less iron-phenolic reactivity compared to ferric pyrophosphate (FePP), due to decreased soluble Fe in the food-relevant pH range 3-7. We investigated reactivity (i.e., complexation, oxidation, and surface interaction) of FePP and mixed salts (with x = 0.14, 0.15, 0.18, and 0.35) in presence of structurally diverse phenolics. At pH 5-7, increased soluble iron from all salts was observed in presence of water-soluble phenolics. XPS confirmed that water-soluble phenolics solubilize iron after coordination at the salt surface, resulting in increased discoloration. However, color changes for mixed salts with x ≤ 0.18 remained acceptable for slightly water-soluble and insoluble phenolics. Furthermore, phenolic oxidation in presence of mixed salts was significantly reduced compared to FePP at pH 6. In conclusion, these mixed Ca-Fe(III) pyrophosphate salts with x ≤ 0.18 can potentially be used in designing iron-fortified foods containing slightly water-soluble and/or insoluble phenolics.

Keywords: Flavonoids; Food fortification; Iron supplementation; Mixed calcium-iron (III) pyrophosphate salts; Polyphenols.

MeSH terms

Diphosphates
Ferric Compounds*
Food, Fortified / analysis
Iron
Phenols
Salts*

Substances

Ferric Compounds
Salts
ferric pyrophosphate
Diphosphates
Iron
Phenols