Regulation of whey protein emulsion gel's structure with pullulan to enhance astaxanthin bioaccessibility

In this study, the potential of using an emulsion gel based on whey protein concentrate (WPC) and pullulan (PUL) to encapsulate and deliver astaxanthin (AST) was investigated. PUL concentration was observed to affect the microstructure of WPC/PUL/AST emulsion gels, and the performance of emulsion gels was evaluated by encapsulation efficiency, simulated gastrointestinal digestion, storage stability, hardness, and water holding capacity tests. The WPC/PUL/AST emulsion gels had the highest encapsulation efficiency, gastrointestinal digestion retention, and bioaccessibility of (91.70 ± 1.47) %, (80.96 ± 5.02) %, and (40.69 ± 1.16) % at 2.0 % PUL concentration, respectively. Furthermore, adding PUL to the emulsion gels improved their hardness, water holding capacity, and storage stability. The findings suggested a potential method to optimize the bioaccessibility of AST in emulsion gels. It provided the possibility for the efficient application of AST as a functional food.