Production and characterization of stable foams with fine bubbles from solutions of hydrophobin HFBII and its mixtures with other proteins

Research output: Contribution to journalArticle

Authors

  • Lydia M. Dimitrova
  • Plamen V. Petkov
  • Peter A. Kralchevsky
  • Simeon D. Stoyanov
  • Edward Pelan

Colleges, School and Institutes

External organisations

  • Sofia University St. Kliment Ohridski
  • Unilever Research and Development
  • Wageningen University and Research Centre
  • UCL

Abstract

Hydrophobins are proteins that are excellent foam stabilizers. We investigated the effects of pH and addition of other proteins on the foaminess, bubble size, and stability of foams from aqueous solutions of the protein HFBII hydrophobin. The produced stable foams have bubbles of radii smaller than 40 μm that obey the lognormal distribution. The overrun of most foams is in the range from 5 to 8, which indicates a good foaminess. The foam longevity is characterized by the time dependences of the foam volume and weight. A combined quantitative criterion for stability, the degree of foam conservation, is proposed. The produced foams are stable for at least 12–17 days. The high foam stability can be explained with the formation of dense hydrophobin adsorption layers, which are impermeable to gas transfer and block the Ostwald ripening (foam disproportionation). In addition, the population of small bubbles formed in the HFBII solutions blocks the drainage of water through the Plateau borders in the foam. The variation of pH does not essentially affect the foaminess and foam stability. The addition of “regular” proteins, such as beta-lactoglobulin, ovalbumin and bovine serum albumin, to the HFBII solutions does not deteriorate the quality and stability of the produced foams up to 94% weight fraction of the added protein. The results and conclusions from the present study could be useful for the applications of hydrophobins as foam stabilizers.

Details

Original languageEnglish
Pages (from-to)92-104
Number of pages13
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume521
Early online date15 Jun 2016
Publication statusPublished - 20 May 2017

Keywords

  • Bubble size distribution, Foam drainage, Foam stability, Foaminess, HFBII hydrophobin, Ostwald ripening

ASJC Scopus subject areas