| Popis: |
lactoglobulin in Tris-HCl buffer pH 7 50 mM was treated with combined pressure and temperature treatments using a central composite experimental design. Pressures studied were up to 294 MPa, temperatures up to 62°C and processing times up to 30 minutes. The molecular structure, at a secondary and tertiary level, was analysed post-processing using far and near-UV circular dichroism. It was found that, although the pressures applied were moderate, the far-UV circular dichroism spectra showed important changes corresponding to an increase in -helical content. The tertiary structure was almost completely lost for the highest processing intensities. This suggests a transition to the molten globule state. The percentage change in ellipticities at 293 nm (tertiary structure) were found to be linearly connected to the three independent variables hence possibly allowing process optimisation for that response. Pressure was found to be the most important parameter to bring about the molecular changes at the two molecular levels investigated. |
