Encapsulation of zeaxanthin dipalmitate emulsion with flaxseed polyphenol and protein isolate improves its stability...

This study aimed to enhance the stability and bioaccessibility of zeaxanthin dipalmitate (ZD) using an oil-in-water emulsion. Flaxseed gum (FG) was used as a stabilizer, while ZD was incorporated through a complex of flaxseed protein isolate (FPI) and flaxseed polyphenols (FPP) (FPI-FPP) to develop the emulsion system. The creaming index, droplet size, and zeta potential of the emulsions with varying oil phase fractions were analyzed. It was observed that as the oil phase fraction increased, the creaming index decreased. Notably, at 0.5 %FG, the droplet size reached its minimum and the distribution was most concentrated. The droplet size was the smallest after one thawing cycle, and the absolute value of zeta potential was the highest. The addition of FG significantly improved the physical and chemical stability of the emulsion. The storage stability and digestive properties of the emulsions were assessed through color difference values, lipid oxidation values, in vitro digestion, free fatty acid release and bioaccessibility. The brightness of FPI emulsions and FPI-FPP emulsions diminished over storage time. The FPI-FPP emulsion exhibited a better retention rate and bioaccessibility of ZD. The successful development of FG-stabilized oil-in-water emulsions provides a novel strategy for delivering water-insoluble bioactive substances.