Non-aqueous Foams Based on Edible Oils
The most common types of foams are aqueous foams. Non-aqueous foams are composed of gas bubbles dispersed in a non-aqueous phase. The physical properties of the non-aqueous liquid phase drive the foaming properties. Contrary to aqueous foams, the foaming properties are not only related to the foaming capacity of the foam stabilizer, but are linked to the nature of the non-aqueous phase and to the interactions between this liquid phase and the foam stabilizer. In the literature, non-aqueous foams are scarcely studied. However, this topic is important for various industries, such as the petroleum industry. New interest in these systems has emerged recently owing to their potential use in low-calorie food products. The non-aqueous foams can be produced based on three different foam stabilizer categories: surfactants, solid particles and crystalline particles. The crystalline particles are also well known in the literature to be involved in the formation of oleogels. Therefore, edible oil foams can be obtained based on oleogels. In this book chapter, the more recent advances in the non-aqueous foams field are described. The mechanisms leading to the formation and stabilization of these non-aqueous foams are described with a focus on oil foams based on oleogel systems.