Rheology of Emulsions

A review of the rheological properties of dilute and concentrated food emulsions

“…There has been considerable interest in the development of various kinds of concentrated emulsions by researchers in the food industry, including high internal phase emulsions (HIPES) (ϕ > 0.64) (Tatar & Sumnu, ), emulsion gels (Solans, Pons, & Kunieda, ) and bi‐liquid foams (Sonneville‐Aubrun et al, ). Concentrated emulsions may possess some advantages over conventional dilute or semi‐dilute emulsions for certain food applications (Piorkowski & McClements, ), such as mayonnaise, dressings, creams, and spreads.…”

“…Researchers have therefore tried to understand the major factors affecting the rheological properties of food emulsions. Many factors are known to be important, including the continuous phase rheology, disperse phase volume fraction, particle size distribution, colloidal interactions, and aggregation state (Tatar & Sumnu, ). These factors can therefore be manipulated to obtain food emulsions with different desirable physicochemical or functional attributes.…”

“…In some food emulsions, the dimensions of the droplets have a major influence on their rheological properties (Tatar & Sumnu, ). The textural properties of these emulsions can then be manipulated by controlling the droplet size, which can be achieved by altering the homogenization method or system composition (such as emulsifier type and concentration).…”

“…The mean droplet diameter and particle size distribution can influence the viscosity of emulsions in numerous ways. At the same oil level, small droplets can have a substantially larger effective volume fraction than larger ones because of the presence of the hydrated interfacial coating (McClements, ; Tatar & Sumnu, ). Moreover, the average distance between droplets decreases as the droplet size decreases, which means that droplet‐droplet interactions become more important (Chen, Chen, & Chiou, ).…”

“…Emulsion rheology is the science that focuses on the flow or deformation of emulsion‐based fluids or solids when forces are applied (Tatar & Sumnu, ). An understanding of the principles and techniques of rheology is important because it allows one to develop effective analytical tools to probe emulsion properties, as well as to optimize the physicochemical properties, sensory attributes, and nutritional value of emulsion‐based foods, such as dressings, mayonnaise, creams, milk, sauces, and soups (McClements, ).…”