Gliadin films

The values of surface potential and fi in Fig. 24 indicate that the number and the orientation of the dipoles in the film, at least on acid and alkaline solutions, does not change as the film is compressed to some 2 dynes this may indicate that the earlier stages of the compression of the gliadin films only bring the ends of the chains R closer together, without removing the COOH or NHa groups at their ends from the water. Further compression, however, rapidly... 

Sanchez, A.C., Popineau, Y, Mangavel, C., Larre, C., and Gueguen, J. Effect of different plasticizers on the mechanical and surface properties of wheat gliadin films, /. Agric. Food Chem., 46, 4539,1998. 

Figure 2. Change of surface pressure with time for gliadin films experiencing submonolayer infections of calcium stearoyl-2-lac tylate ( ), Myrj 45 (A), Tween 60 ( Q), Brij 35 ( ), Brij 76 (O),...

In general, as a protein film is compressed the potential difference AF increases. Examination of equation 6 shows that this increase could be due to increasing number of molecules per unit area, to a decrease in 6, i.e., to an orientation of the dipoles normal to the surface, or to a decrease of D. It is commonly assumed that D remains constant as the film is compressed (20). If D actually remains constant as the film is compressed, then the potential difference should be a function only of n and the angle of tilt, n can be calculated from the area of the film and any variation in AF/n should be a function only of cos 0. For gliadin films, for serum albumin films, for j3-IactoglobuIin films and for... 

To compensate for any additivity effects of the surfactants and gliadin we spread surfactant solutions, in the amounts used in the experiments, on the film balance. No significant surface pressure was observed over the entire compression range, indicating that the surfactants did not contribute directly to the surface pressure measurements. 

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