Heat Gelation of Oil‐in‐Water Emulsions Stabilized by Whey Protein

Abstract

The conditions under which a high volume fraction of oil can be trapped in whey protein gels were studied. Oil-in-water emulsions of whey protein and vegetable oil were subjected to heat treatment. Such emulsions, depending on their protein and oil content, on their pH and on the emulsification technique used, gelled or remained liquid. Homogenization was the major factor to achieve gelation and the firmness of heat-induced gels increased with increasing emulsion fineness and homogeneity. Emulsions with a high gelation capacity were characterized by a single droplet family of relatively narrow size distribution and a mean droplet diameter ranging from roughly 300-700 nanometers. The pH range suitable for gelation extended from 3.5-8.0.

Aggregated whey proteins and trace of caseins synergistically improve the heat stability of whey protein-rich emulsions

“…However, heat treatments can cause detrimental changes in some products such as liquid protein-stabilized emulsions due to the heat instability of the proteins adsorbed at the surface of fat droplets and in the dispersing phase (Çakir-Fuller, 2015;Dybowska, 2011;Euston, Finnigan, & Hirst, 2000). Heating leads to the flocculation and coalescence of the fat droplets and in extreme cases to gelation of the emulsion (Çakir-Fuller, 2015;Demetriades, Coupland, & McClements, 1997;Euston et al, 2000;Hunt & Dalgleish, 1995;Jost, Baechler, & Masson, 1986;Yamauchi, Shimizu, & Kamiya, 1980;Yost & Kinsella, 1992). To prevent such instability, manufacturers used to add non-protein additives (such as carrageenans, pectins, mono and diglycerides of fatty acids) that are able to keep the fat droplets away from each other.…”

Characterization of whey protein emulsion films

“…Emulsion stability is affected by film morphology, by continuous phase characteristics (pH, viscosity, ionic strength) and by the dispersed phase (size, density of lipid droplet) (Pérez-Gago and Krochta, 1999). Protein and lipid interactions at the interfacial surface depend on homogenization and droplet size (Jost et al, 1986).…”

Protein-lipid interactions in edible films and coatings

“…For example, formation and firmness of heat-induced gels were improved with increasing emulsion fineness and homogeneity [21]. Observations such as this prompted several studies investigating the effects of various emulsion characteristics on properties of films formed from these systems.…”