Disulfide cleavage to improve interfacial behavior and emulsification properties of oat protein

Runnan Li, Youling L. Xiong

Research output: Contribution to journalArticlepeer-review

Abstract

Disulfide bonds play an essential structural role but may hinder the molecular flexibility and functionality of proteins. The present study investigated the effect of disulfide cleavage on emulsifying activity of oat protein isolate (OPI). Four reducing agents tested (dithiothreitol, ascorbic acid, cysteine, and sodium bisulfite) except ascorbic acid disrupted inter-subunit S[sbnd]S bonds of OPI (up to 90 %) in a dose-dependent manner. Emulsification properties were measured specifically on cysteine-modified OPI, and the results showed increased emulsifying activity up to 37 % after subunit dissociation, which exposed hydrophobic groups and loosened the structure. In particular, emulsions formed by cysteine-treated OPI (1.7 to 6.7 mM/mg protein) displayed a superior interfacial protein coverage (0.170 m2/mg compared to 0.092 m2/mg for control) and reduced emulsion particle size (from 4722 to 2238 nm). The application of cysteine as a structure-modifying food additive can broaden the utilization of oat protein in emulsion-based food products.

Original languageEnglish
Article number134511
JournalFood Chemistry
Volume404
DOIs
StatePublished - Mar 15 2023

Bibliographical note

Funding Information:
This work is supported by the USDA National Institute of Food and Agriculture, Hatch project 1020736. The authors thank Dr. Thomas Wilkop at the Light Microscopy Core of the University of Kentucky for assisting the confocal imaging analysis.

Publisher Copyright:
© 2022 Elsevier Ltd

Keywords

  • Cysteine
  • Disulfide bonds
  • Emulsification properties
  • Oat protein
  • Reducing agents

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science

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