Swelling and dissolution of beta-lactoglobulin gels in alkali.
It is well documented in the literature that during the dissolution of whey protein gels in alkali, the gels swell to a great extent. However, the relevance of the swelling step in the dissolution process of the protein gel remains unknown. In the present article we present a systematic study on the swelling of beta-lactoglobulin gels at different alkaline pH and ionic strengths. The equilibrium swelling degree at different conditions has been modeled using a simple model developed for polyelectrolyte gels, modified to take into account the ionization of the residues in a protein. The model can describe the swelling behavior of the gels over a wide range of conditions, but it underpredicts the equilibrium swelling under conditions close to those when dissolution is observed. Dissolution is only noticeable above pH 11.5-12 and only for those gels that are swollen over a minimum degree, suggesting the existence of a dissolution threshold.
Mercadé-Prieto
Ruben
R
Department of Chemical Engineering, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, United Kingdom.
Falconer
Robert J
RJ
Paterson
William R
WR
Wilson
D Ian
DI
D000042:Absorption; D000468:Alkalies / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry*; D008956:Models, Chemical; D009994:Osmolar Concentration; D012996:Solutions; D014867:Water / Q000737:chemistry*
D000468:Alkalies; D005782:Gels; D007782:Lactoglobulins; D012996:Solutions; D014867:Water