Abstract
In this study, structural changes in micellar caseins and whey proteins due to high pressure--low temperature treatments (HPLT) were investigated and compared to changes caused by high pressure treatments at room temperature. Whey protein isolate (WPI) solutions as well as micellar casein (MC) dispersions and mixtures were treated at 500 MPa (pH 7.0 and 5.8) at room temperature, -15 °C and -35 °C. Surface hydrophobicity and accessible thiol groups remained nearly unchanged after HPLT treatments whereas HP treatments at room temperature caused an unfolding of the WPI, resulting in an increase in surface hydrophobicity and exposure of the thiol groups. For HPLT treatments, distinct changes in the secondary structure (increase in the amount of β-sheets) were observed while the tertiary structure remained unchanged. Large flocs, stabilized by hydrophobic interactions and hydrogen bonds, were formed in casein containing samples due to HPLT treatments. Depending on the pH and the applied HPLT treatment parameters, these interactions differed significantly from the interactions determined in native micelles.
References
Jan 1, 1977·Annual Review of Biophysics and Bioengineering·F M Richards
Aug 31, 1988·Biochimica Et Biophysica Acta·P T Wong, K Heremans
Jan 1, 1972·Progress in Biophysics and Molecular Biology·A A Zamyatnin
Jun 22, 1971·Biochemistry·S A Hawley
Mar 18, 1980·Biochemistry·B C SchadeR Jaenicke
Jun 12, 1994·Biochimica Et Biophysica Acta·E DufourT Haertlé
Jun 1, 1996·International Journal of Biological Macromolecules·N TanakaS Kunugi
Sep 20, 2000·Journal of Agricultural and Food Chemistry·J BelloqueG M Smith
Jul 17, 2001·Journal of Agricultural and Food Chemistry·J YangB G Swanson
Oct 9, 2001·Journal of Chromatography. a·G BordinA R Rodriguez
May 2, 2002·Biochimica Et Biophysica Acta·László Smeller
May 1, 1959·Archives of Biochemistry and Biophysics·G L ELLMAN
Apr 8, 2004·The Journal of Dairy Research·Thom HuppertzAlan L Kelly
Jan 18, 2006·Biochimica Et Biophysica Acta·Thom HuppertzAlan L Kelly
May 6, 2006·The Journal of Dairy Research·Thom HuppertzCornelis G de Kruif
Aug 3, 2006·Journal of Agricultural and Food Chemistry·Thom Huppertz, Cornelis G de Kruif
Mar 19, 2008·Journal of Agricultural and Food Chemistry·KeShun Liu, Fu-Hung Hsieh
Jun 28, 2008·Biophysical Chemistry·Yan Liu, Rong Guo