NMR method in the study of the interfacial adsorption layer of gelatin

The interfacial adsorption layers of gelatin at a benzene/gelatin solution in D2O interface were studied by NMR using the oil-in-water emulsions prepared by ultrasonic dispersion in conditions where the gelatin macromolecules are in a coiled conformation. The intensities of the proton signals from the gelatin decreased and the NMR spectral lines broadened upon the formation of interfacial adsorption layers of gelatin (T > 313 K). The result is similar to that of collagen-like helices and gels of gelatin and shows that the fraction of mobile gelatin segments in interfacial adsorption layers decreases virtually to zero. The presence of two different signals in the NMR spectrum suggests that benzene is solubilized by gelatin macromolecules and constitutes one component of the interfacial adsorption layer of gelatin