Cold-Set Emulsion Gels Costabilized by Kidney Bean Protein Isolate and Basil Seed Gum as Astaxanthin Carriers: Improved Stability and Bioaccessibility

Abstract

The functional and structural properties of glucono-δ-lactone (GDL) or/and sodium citrate (SC) induced-cold-set emulsion gels stabilized by kidney bean protein isolate and basil seed gum were investigated, and an in vitro digestion model was established to explore the delivery of astaxanthin. A 50% oil-phase fraction greatly elevated the particle size and the viscosity of the O/W emulsion and improved the gel strength, water holding capacity, and creep-recovery properties of the emulsion gels. Furthermore, the water holding capacity of the flexible SC-induced emulsion gel was improved, and the bioavailability of astaxanthin was increased from 10% to 50%. In contrast, GDL and GDL/SC dual-induced emulsion gels had higher strength, resulting in 12% and 12.5% release of free fatty acid during digestion, which was unfavorable for the digestion and absorption of astaxanthin. These outcomes suggested that the novel emulsion gels were effective and stable carriers for the design of hydrophobic bioactive compounds.