Fabrication and characterisation of whey protein isolate–propolis–alginate complex particles for stabilising α-tocopherol-contained emulsions

Abstract

Dairy proteins are being used as carrier materials for the co-encapsulation and protection of bioactive nutrients because of their emulsification and complexation with polysaccharides. In this study, whey protein isolate (WPI)-propolis and WPI-propolis-alginate complex particles were fabricated at pH 7.0 and characterised in term of size distribution, ζ-potential, antioxidant activity, and propolis encapsulation. The encapsulation efficiency of propolis was above 80% when 5 mg mL−1 WPI was incorporated. Propolis and α-tocopherol were further co-encapsulated in sunflower oil emulsions stabilised by the complex particles. About 92% α-tocopherol and 72% propolis were co-encapsulated in the inner oil phase and the oil-water interface of emulsions, respectively. Propolis and/or alginate improved the stability of α-tocopherol during storage, while sodium alginate counteracted the positive effect of propolis on the vitamin stability during enzymatic hydrolysis. The data gathered here would expand the use of biopolymer-stabilised emulsions for multi-nutraceutical delivery.