Enhancing lutein stability and bioaccessibility with high internal phase emulsions stabilized by octenylsuccinylated starch

Lutein possesses antioxidant properties and is a main component of the macular pigment, vital for infant eye and brain development. However, its use is constrained by its poor aqueous solubility and low stability. High internal phase emulsions (HIPEs) are valued in food development for encapsulating and protecting hydrophobic nutraceuticals. The objective of this study is to improve lutein's stability and bioaccessibility using HIPEs stabilized by biopolymer octenylsuccinylated starch (OSS). Three types of commercial OSS, including CAPSUL TA (CTA), HI-CAP 100 (HC), and Purity Gum 2000, were tested for their emulsification properties in forming lutein HIPEs. Lutein HIPEs stabilized by 15%-25% CTA and 15%-30% HC had no phase separation and were selected for subsequent testing. After 21 days of storage at room temperature, lutein HIPEs showed higher lutein retention compared to free lutein. Lutein HIPEs stabilized with higher emulsifier concentrations (25% CTA and 30% HC) exhibited greater droplet diameter stability than those with lower concentrations. Additionally, lutein HIPEs significantly enhanced lutein retention under UV exposure and thermal stress. The in vitro bioaccessibility of lutein was highest in the HIPE stabilized by 20% CTA, reaching 54.36%. In conclusion, lutein HIPEs stabilized by 20% CTA demonstrated superior lutein stability and bioaccessibility, showing significant potential as an effective lutein delivery system.