Chapter 8: High Internal Phase Emulsions

Innovations in emulsion science, particularly the development and deployment of novel emulsion types, have gained considerable attention in the food industry recently. This chapter focuses on one of these advanced emulsion technologies: high internal phase emulsions (HIPEs). HIPEs have internal phase volume fractions exceeding the close packing limit (usually >74%), which leads to semi-solid textural properties and a high resistance to gravitational separation. HIPEs are usually stabilized by surfactants, polymers, colloidal particles, or their mixtures, which can be either synthetic or natural. We review the different approaches that have been utilized to produce HIPEs and highlight their advantages and disadvantages. We also discuss recent research on the impact of the composition and structure of HIPEs on their physicochemical and functional attributes, e.g., appearance, rheology, encapsulation, delivery, and gastrointestinal fate. Finally, future trends of HIPEs in the food industry are discussed.