Foaming properties of wheat gliadin.
We studied gliadin solubility, surface tension and foam behavior, and the presence of different gliadin types in gliadin aqueous solutions and foams as a function of pH. Gliadin has excellent foaming properties only at neutral and alkaline pH. Its solubility is minimal near neutral pH, while almost complete at acidic and alkaline pH. Surface tensions of gliadin solutions are minimal around neutral pH, higher at alkaline pH, and highest at acidic pH, which corresponds well with their respective foaming properties. Foams at acidic and alkaline pH values are enriched in γ-gliadin, while foams at pH 8.0 have a similar distribution of α- and γ-gliadins. Thus, γ-gliadin predominantly contributes to the foaming properties of gliadin. The poor foaming properties of gliadin at pH 2.0 improve in the presence of 0.25 and 1.0% NaCl. It follows that the presence of positively charged amino acid residues hinders the formation of stable foam at acidic pH.
Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven , Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Bert G
BG
Thewissen
Inge
I
Celus
Kristof
K
Brijs
Jan A
JA
Delcour
D055598:Chemical Phenomena / Q000187:drug effects; D005903:Gliadin / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D013500:Surface Tension; D014908:Triticum / Q000737:chemistry*
D012965:Sodium Chloride; D005903:Gliadin