Food proteins as potential carriers for phenolics

M.C. Bohin

Research output: Thesisinternal PhD, WU

Abstract

The development of phenolic-rich functional foods is often limited by the off-tastes of phenolics that might be counteracted by sequestering these compounds using a carrier, thereby preventing them to interact with bitter taste receptors and salivary proteins. A range of common animal food proteins were tested for binding of phenolics. It appeared that a proline-rich open protein structure, as in β-casein, favored binding of phenolics. Globular proteins other than bovine serum albumin showed poor potential for use as carrier. No appropriate carriers for monomeric phenolics were found. β-Casein and Na-caseinate were shown to have good bitter-masking potential for EGCG, as measured by a maximal reduction in bitter receptor activation of ~93% measured in vitro. This effective reduction in bitter receptor activation was confirmed by a sensory test. This illustrates the validity of using food proteins with good binding properties as carriers for phenolics.

Different methodologies for probing the interaction between proteins and phenolics were developed: (i) ultrafiltration followed by UV quantification of unbound phenolics in the retentate, (ii) fluorescence quenching, and (iii) ultrafiltration followed by mass spectrometric quantification of unbound phenolics in the retentate. The latter method offered the opportunity to analyze preferential binding to protein of individual phenolics present in a complex mixture. With these methods, it was established that, with respect to phenolics, conformation and flexibility were important drivers of protein-phenolic interaction, besides degree of polymerization and galloylation. With respect to relatively proline-poor unstructured proteins such as α-casein and β-casein, it appeared that there should be other factors, besides proline density, explaining the interaction with phenolics.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Gruppen, Harry, Promotor
  • Vincken, Jean-Paul, Co-promotor
Award date25 Oct 2013
Place of PublicationS.l.
Print ISBNs9789461736765
Publication statusPublished - 2013

Keywords

  • proteins
  • phenolic compounds
  • casein
  • caseinates
  • bitterness
  • interactions

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