Interfacial competition between soluble and aggregated proteins: droplets connectivity and dairy emulsions texture

Supervisors : Marc Anton (director), Alain Riaublanc, Catherine Garnier, Thomas Croguennec

Abstract

The texture of many unfermented fat dairy products is generally obtained by using food additives added for purely technological purpose. Nowadays, the removal of these in foodstuffs is a real societal request. In order to provide an answer to this challenge, this thesis project aims to find an alternative texturing mechanism for emulsions by using different types of milk protein aggregates without using additives. Indeed, under some physicochemical conditions, these aggregates are able to connect the fat droplets in order to form network which, once the conditions had been understood, could control the texture of the emulsions. For this purpose, emulsions were produced by varying the concentration of different aggregates types, native whey proteins and non-micellar caseins. By controlling the nature of the proteins present at the interface, it allows to cover a wide range of texture. Moreover, depending on the aggregates concentration at the interface, it is also possible to control the texturing kinetics of the emulsions which can be reached both during the homogenization step and during storage. Thus, by controlling the competition to cover the interfaces and the interactions between them, we have shown that the macroscopic texture of the emulsions can be directly correlated with the interfacial composition. This texturing mechanism using proteins aggregates is a serious way for the substitution of additives in dairy emulsions in order to offer consumers more natural products.