Abstract
Fat plays a crucial role in food applications, affecting texture, mouthfeel, and stability. However, traditional solid fats are rich in saturated fats, which pose health risks. To address this, the food industry is exploring alternatives such as replacing saturated fats with unsaturated fats or lowering overall fat content. One promising approach is the use of aerated oils or oil foams, where air is incorporated into oil to reduce fat while imparting solid-like properties. This study aimed to investigate the potential of different dairy proteins to stabilize oil foams in addition to using food-grade surfactants as stabilizers. Protein powders based on casein micelles or whey proteins, with or without milk fat and lactose, were tested alongside a model surfactant to evaluate their effects on sunflower oil foam formation and stability. The impact of protein type, concentration, oil type, and temperature on foam properties was systematically assessed. Foam stability was mainly influenced by the protein powders' tendency to sediment and/or the presence of agglomerates rather than their protein content or type. Powders high in milk fat and lactose were denser, contained less occluded air, and produced unstable foams, while fat- and lactose-free powders, especially those rich in casein, formed highly stable foams. Adding dairy powders rich in casein at 30 wt% significantly improved long term foam stability at room temperature. These findings demonstrate that proteins powders can improve oil foam stability by reducing drainage depending on the powder composition. Such protein-stabilized oil foams offer potential to improve the nutritional profile of diverse food products.