Anisotropic protein films

The reorganization free energy is usually split in two parts. The local mode contribution is obtained in standard routines which require local potentials (say harmonic potentials) and vibrational frequencies in the reactants and products states. The collective modes associated with the proteins and the solvent, however, pose complications. One complication arises because classical electrostatics needs modification when the spatial extension of the electric field and charge distributions are comparable with the local structure extensions of the environment. Other complications are associated with the presence of interfaces such as metal/solution, protein/solution, and metal/film/solution interfaces. These issues are only partly resolved, say by nonlocal dielectric theory and dielectric theory of anisotropic media. 

Finally, protein-based fibrils can be formed and may be used to increase the stability of the interfacial film in spray-dried microcapsules. In concentrated protein solutions depending on the environmental conditions (pH, ionic strength, temperature) and the process conditions (e.g. shear), fibril structures or spherical aggregates may occur as a result of hydrolysis and denaturation [41,42]. In literature the formation of fibrils using p-lactoglobulin and whey protein isolate is described. These amyloid-like anisotropic aggregates are formed at pH values below the isoelectric point (pH 2.0. 0) and several hours of heating (at or above 80 °C)... 

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