Effects of ionic strength and denaturation time on polyethyleneglycol self-diffusion in whey protein solutions and gels visualized by nuclear magnetic resonance.
Pulsed field gradient NMR spectroscopy was used to determine the poly(ethylene glycol) (PEG) self-diffusion coefficient (D(PEG)) as a function of NaCl concentration (C(NaCl)) and denaturation time (t(D)) in whey protein solutions and gels. D(PEG) in the gel decreased with increasing C(NaCl) concentrations and increased with increasing t(D); the increase ceased for all PEGs when the gel was fixed. This increase was more pronounced for the 82250 g/mol PEG than the 1080 g/mol PEG. Moreover, the diffusion coefficient of nonaggregated whey protein was measured and an increase for longer t(D) was also observed. Scanning electron microscopy images and (1)H spectra demonstrated that D(PEG) were related to the structure changes and to the percentage of beta-lactoglobulin denaturation.
Colsenet
Roxane
R
Process Engineering Technology Research Unit, Cemagref, CS 64426, 17 Avenue de Cucillé, 35044 Rennes, Cedex, France.
Söderman
Olle
O
Mariette
François
F
D004058:Diffusion; D005782:Gels; D006358:Hot Temperature; D007782:Lactoglobulins / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008894:Milk Proteins / Q000737:chemistry*; D009994:Osmolar Concentration; D011092:Polyethylene Glycols / Q000737:chemistry*; D011489:Protein Denaturation; D012965:Sodium Chloride; D012996:Solutions; D013997:Time Factors; D000067816:Whey Proteins
D005782:Gels; D007782:Lactoglobulins; D008894:Milk Proteins; D012996:Solutions; D000067816:Whey Proteins; D011092:Polyethylene Glycols; D012965:Sodium Chloride