α-Tocopherol and resveratrol in emulsion-filled whey protein gels: Co-encapsulation and in vitro digestion

Assemblies with multiple domains have been suggested as potential carriers for co-encapsulation of bioactive components with different solubilities. Although protein emulsion gels contain a dispersed oil phase and a gel network, there is no report about their use for co-encapsulation. Heat-denatured WPI particles and emulsions with 10% and 25% oil were characterised by size, ζ-potential and viscosity. The total encapsulation efficiency of resveratrol and α-tocopherol was around 60% and 98%, respectively, most located in the oil droplets. Cold-set gels were further fabricated with 10–100 mmol L−1 CaCl2 and characterised in terms of syneresis, water holding capacity and hardness. During in vitro digestion, α-tocopherol and resveratrol were completely released from the gels. After digestion, resveratrol remained above 50% and the highest (∼85%) at 10 mmol L−1 CaCl2 in the absence of oil, but α-tocopherol remained only 25%. These results should be useful for the development of co-encapsulating carriers.