Preparation and characterization of emulsion-filled gel beads for the encapsulation and protection of resveratrol and α-tocopherol

Proteins and polysaccharides have been widely used as wall materials to prepare novel carriers for the encapsulation of a single bioactive component or co-encapsulation of different bioactive components. Emulsion filled gel beads generally contain three essential components: oil droplets, interface membrane of emulsifier, and gel matrix. In this study, emulsion-filled gel beads were prepared by the combination of heat-denatured whey protein isolate (WPI)'s emulsification and alginate's gelation at various protein and oil contents, in order to discuss simultaneous encapsulation, protection and release of hydrophobic a-tocopherol and amphiphilic resveratrol. High efficiency for the co-encapsulation of resveratrol and a-tocopherol was achieved for the emulsion-filled gel beads containing 1% WPI and 1%-4% oil. WPI content was more important than the content of oil for the protection of resveratrol while the content of oil was more important for the encapsulation and protection of a-tocopherol during storage. The release of a-tocopherol was < 20% while resveratrol was rapidly released during digestion. Resveratrol remained 73% after released from the emulsion-filled gel beads containing 1% WPI and 1%-2% oil for 6 h. These results should be useful for the development of biopolymer-based carriers for the delivery of different bioactive components.