COLL 229 |
| To better understand what happens to casein micelles in the dairy processing industry, the effects of various protein-solution interactive forces derived from processing conditions (temperature, concentration, ethanol and pH) on the molecular conformations of casein micelles have been investigated by dynamic and static light scattering. The hydrodynamic radius (Rh) of casein micelles decreased generally with increasing temperature in the presence or absence of ethanol, indicating the dissociation of casein micelles. It was a reversible dissociation for thermal treatment of casein in the presence of ethanol or aqueous casein with a lower concentration. By contrast, heat-induced dissociation of aqueous casein micelles with a higher concentration was irreversible. The Rh value of casein micelles decreased and then increased with their increasing concentration at room temperature (20~30°C). As the concentration of ethanol increased from 0 to 40%, the Rh value of protein molecules increased gradually, suggesting the aggregation of casein micelles. The molecular weight and gyration radius of casein micelles were determined to be approximately 4.25 million Dalton and 169nm, respectively, at pH 8.0 and 25°C, which both increased with the decreasing pH value.
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Fundamental Research in Colloid and Surface Chemistry
6:00 PM-8:00 PM, Monday, August 20, 2007 BCEC -- East Registration, Poster
Division of Colloid & Surface Chemistry |
