Eureka! Institutional Repository

The events occurring during the spontaneous mixing of okra mucilage-based model emulsion food with saliva were recorded, with a focus on the local dynamics of colloidal particles contained in the system. An okra mucilage containing fluorescent negatively-charged microsphere probes (taking the role of the emulsion droplets), was brought into contact with reconstituted saliva on the welled slide of a confocal microscope. The translational movement of the probes at the saliva–mucilage interface and in the bulk mucilage has been recorded over periods of 60 minutes. Data have been obtained on the total mobility of individual model droplets, from which their diffusion coefficients and the local viscosities were calculated, providing information on the dynamics of processes that occur during the oral processing of colloidal liquids. The role of osmotic pressure gradients on the mixing of the droplets into saliva is discussed in relation to the microrheology data.