Composition of thin films between emulsion droplets stabilized by protein, as measured in highly concentrated emulsions

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 26; no. 3; pp. 269 - 279
• Main Authors: van Aken, George A., Zoet, Franklin D., Diederen, Julia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2002
• Subjects: air-water-interface; coalescence; foams; Highly concentrated emulsions; NMR; protein adsorption; protein stabilized emulsions; rheology; thin films; protein adsorption; NMR; Highly concentrated emulsions; protein stabilized emulsions; thin films
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/S0927-7765(02)00010-3

Oil-in-water emulsions stabilized by whey protein and β-lactoglobulin are extremely stable to coalescence, provided a saturated adsorbed protein layer is present at the droplet surfaces. If this is the case, these emulsions can be concentrated to stable highly concentrated emulsions, in which the droplets are in continuous contact and separated by thin films. The water content in these highly concentrated emulsions could be lowered to such an extent that almost all of the protein in the emulsion was present in the adsorbed layers at both sides of the thin films separating the emulsion droplets. Therefore, these systems are convenient for determination of the composition and mechanical properties of adsorbed protein layers in thin films between emulsion droplets. At the lowest water content obtained by us, the mobility of water was strongly reduced as measured by NMR, suggesting that hardly any water was present in the Plateau borders and that most of the remaining water was held within the adsorbed protein layer in the thin film regions between the emulsion droplets. The amount of protein and water remaining in the highly concentrated emulsion corresponded well with compositions of adsorbed protein layers as described in the literature, suggesting that these thin films are composed of two layers of adsorbed protein.