Development of iron-rich whey protein hydrogels following application of ohmic heating - Effects of moderate electric fields

Ricardo N Pereira; Rui M Rodrigues; Emir Altinok; Óscar L Ramos; F Xavier Malcata; Paola Maresca; Giovanna Ferrari; José A Teixeira; António A Vicente

doi:10.1016/j.foodres.2017.05.023

Development of iron-rich whey protein hydrogels following application of ohmic heating - Effects of moderate electric fields

Food Res Int. 2017 Sep;99(Pt 1):435-443. doi: 10.1016/j.foodres.2017.05.023. Epub 2017 May 29.

Authors

Ricardo N Pereira¹, Rui M Rodrigues², Emir Altinok³, Óscar L Ramos⁴, F Xavier Malcata⁵, Paola Maresca⁶, Giovanna Ferrari⁷, José A Teixeira², António A Vicente²

Affiliations

¹ CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal. Electronic address: rpereira@deb.uminho.pt.
² CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
³ Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA, Italy.
⁴ CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, University of Porto, Porto, Portugal.
⁵ LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, University of Porto, Porto, Portugal; Department of Chemical Engineering, University of Porto, Porto, Portugal.
⁶ ProdAl Scarl - University of Salerno, via Ponte don Melillo, 84084 Fisciano, (SA), Italy.
⁷ Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA, Italy; ProdAl Scarl - University of Salerno, via Ponte don Melillo, 84084 Fisciano, (SA), Italy.

PMID: 28784503
DOI: 10.1016/j.foodres.2017.05.023

Abstract

The influence that ohmic heating technology and its associated moderate electric fields (MEF) have upon production of whey protein isolate cold-set gels mediated by iron addition was investigated. Results have shown that combining heating treatments (90°C, 5min) with different MEF intensities let hydrogels with distinctive micro and macro properties - i.e. particle size distribution, physical stability, rheological behavior and microstructure. Resulting hydrogels were characterized (at nano-scale) by an intensity-weighted mean particle diameter of 145nm, a volume mean of 240nm. Optimal conditions for production of stable whey protein gels were attained when ohmic heating treatment at a MEF of 3V∙cm^-1 was combined with a cold gelation step using 33mmol∙L^-1 of Fe²⁺. The consistency index of hydrogels correlated negatively to MEF intensity, but a shear thickening behavior was observed when MEF intensity was increased up to 10V∙cm^-1. According to transmission electron microscopy, ohmic heating gave rise to a more homogenous and compact fine-stranded whey protein-iron microstructure. Ohmic heating appears to be a promising technique, suitable to tailor properties of whey protein gels and with potential for development of innovative functional foods.

Keywords: Cold gelation; Electric fields; Iron; Transmission electron microscopy; Whey protein isolate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Electric Conductivity
Electricity*
Ferrous Compounds / analysis*
Food Handling / methods*
Food, Fortified / analysis*
Heating*
Hydrogels
Microscopy, Electron, Transmission
Nanoparticles
Nutritive Value
Protein Conformation
Viscosity
Whey Proteins / analysis*

Substances

Ferrous Compounds
Hydrogels
Whey Proteins
ferrous sulfate