Emulsifiers in Dairy Products and Dairy Substitutes

Low molecular weight emulsifiers are used for a number of functions in dairy products and dairy substitutes. These include their surface-active properties, ability to promote fat crystallization, interactions with proteins, and antimicrobial activity. In this chapter, we review the role of low molecular weight surfactants across a range of products manufactured by the dairy industry. In ice cream and whipped dairy emulsions, the surface activity of emulsifiers allows them to adsorb to the surface of air bubbles in foams, or to the surface of oil droplets in emulsions, thus facilitating formation of smaller bubbles and droplets and helping to control the stability. Emulsifiers also play a role in nucleation of fat crystallization in ice cream and whipping cream, and contribute to the structure and stability of these products by promoting the partial coalescence that helps to stabilize the foams. In cream liqueur, as well as aiding formation of small, stable emulsion droplets, mono glyceride emulsifiers are able to interact with the casein proteins added for emulsification. This synergy allows a reduction in casein content that improves acid stability if the liqueur is used as a mixer. A similar effect is observed in coffee whitener, where protein-emulsifier interactions give improved acid stability, in processed cheese where electrostatic interactions between anionic emulsifiers and proteins can be exploited to alter the texture, and in recombined and concentrated milks where lecithin protein interactions can improve heat stability.