Heat-Induced Aggregation of Whey Proteins in Aqueous Solutions below Their Isoelectric Point

L. Cornacchia, C. Forquenot de la Fortelle, P. Venema

Research output: Contribution to journalArticleAcademicpeer-review

17 Citations (Scopus)

Abstract

Processing beverages containing high concentrations of globular proteins represents a technological challenge due to their instability during heating caused by protein aggregation and gelation. Aggregation of whey protein mixtures was investigated in aqueous model systems at pH 3.5, 4.0, and 4.5 at heating conditions resembling conventional industrial treatment (90 °C for 30 s). The extent of aggregation progressively decreased moving away from the pI. Protein aggregates became smaller and had a more open structure compared to higher pH values. Significant loss of protein dispersibility occurred at pH 4.0 and 4.5 above the denaturation T of whey protein (~70 °C), at which aggregation was caused by intermolecular hydrophobic interactions. Accessible thiol groups were detected in the heat-treated systems, with a higher intensity at higher pH and increasing extent of aggregation. Intermolecular -S-S- bonding played only a minor role in the aggregation at all conditions studied.
Original languageEnglish
Pages (from-to)733-741
JournalJournal of Agricultural and Food Chemistry
Volume62
DOIs
Publication statusPublished - 2014

Keywords

  • bovine beta-lactoglobulin
  • disulfide bonds
  • interchange reactions
  • thermal-denaturation
  • alpha-lactalbumin
  • particulate gels
  • induced gelation
  • ionic-strength
  • ph 2
  • solubility

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