Changes and roles of secondary structures of whey protein for the formation of protein membrane at soy oil/water interface under high-pressure homogenization.
The conformational changes of whey proteins upon adsorption at the soy oil/water interface were investigated using Fourier transform infrared (FT-IR) spectroscopy. Significant changes were observed in the bands assigned to beta-sheets and alpha-helix structures following the adsorption of proteins at the oil/water interface. The remaining interfacial proteins after Tween 20 desorption revealed small changes in beta-sheet and alpha-helical structures, whereas in the desorbed whey proteins the unordered structures largely increased, and beta-sheet structures almost disappeared. These FT-IR results provide important knowledge about the conformational modifications in whey proteins occurring upon adsorption at the oil/water interface. Finally, specific conformational changes are necessary to stabilize emulsions: adsorption-induced unfolding, increase in alpha-helical structures to establish interactions with the oil phase, and aggregation between adsorbed whey proteins to form protein membranes. Moreover, the structural changes in whey protein adsorbed at the oil/water interface under high-pressure homogenization are irreversible.
Lee
Sang-Ho
SH
Busan regional Korea Food & Drug Administration, Korea. salutsh@hanmail.net
Lefèvre
Thiery
T
Subirade
Muriel
M
Paquin
Paul
P
D000327:Adsorption; D004655:Emulsions / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013024:Soybean Oil / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry*; D000067816:Whey Proteins
D004655:Emulsions; D008894:Milk Proteins; D000067816:Whey Proteins; D014867:Water; D013024:Soybean Oil