Stability, rheology, and β-carotene bioaccessibility of high internal phase emulsion gels

High internal phase emulsions (HIPEs) were prepared using preheated whey protein isolate (WPI). The influence of cold-set gelation induced by addition of glucono-δ-lactone (GDL) on the microstructure, rheology, water holding capacity (WHC), and stability of HIPEs was determined. In the presence and absence of GDL, the mean particle diameters of HIPEs decreased with increasing WPI concentration. The addition of GDL to the HIPEs did not alter their mean particle diameter or microstructure. The gel strength, hardness, WHC, and stability of HIPEs increased with increasing WPI concentration and with GDL addition. An in vitro digestion experiment showed that β-carotene retention and bioaccessibility was higher after GDL was added to the HIPEs. These findings may be useful for the development of HIPE-based delivery systems for food and other applications.