Continuing yet mostly reversible structuration of gum arabic in the presence of oil at interface

International audience ; To understand the long-term self-association of gum arabic (GA) in water, the time-course development during aggregation of GA molecules with or without an oil/water interface was studied. A simple experimental setup, using a rheometer was employed. The transparent cone-plate geometry was filled with gum arabic solution, and the periphery of the geometry was covered with oils or left uncovered. The observed time-course increase in shear modulus revealed that the continuous structuration of GA molecules occurs in the presence of oil at the interface. The network structure of the GA molecules was mostly re-dispersible with a flow test. In addition, the degree of structuration of GA aggregates depended on the type of oil. The physical properties of the aqueous GA solution, as measured by the rheological experimentation, were found to be strongly influenced by the interfacial conditions, namely air/water or oil/water.