Developing Biopolymer-Based Lutein Emulsion to Improve the in Vitro Bioaccessibility of Lutein and its in Vivo Bioavailability in Neonatal Rats

Oxidative stress is a major pathogenic factor in many neonatal diseases. Immature tissues at birth, such as the retina and the brain, are particularly vulnerable to oxidative stress due to their high metabolic rate. Lutein, a dietary antioxidant from leafy vegetables, acts as the macular pigment in the eye and protects the macula from light-initiated oxidative damage. However, the low bioavailability and stability of lutein limit its application as a nutritional intervention. The aim of this research was to develop a novel emulsion system for lutein using food-grade colloids as emulsifiers to improve its storage stability, in vitro bioaccessibility, and bioavailability in neonatal rats.Six types of biopolymers that are safe for infant foods, including three types of octenylsuccinated starches (CTA, HC, and PG) and three types of gum Arabic (TM, TAM, and PHGA), were chosen as emulsifier candidates to prepare biopolymer-based oil-in-water emulsions. The emulsions stabilized by CTA, HC, and TM possessed superior stability by forming gel-like emulsions and were used to prepare lutein emulsions. CTA-, HC-, and TM- stabilized lutein emulsions all exhibited a compact emulsion network and small droplet size. However, the CTA-stabilized lutein emulsion showed the overall best performance in enhancing the storage stability and in vitro bioaccessibility of lutein and was selected for the in vivo studies. In an acute dosing study, neonatal Sprague-Dawley rats received a single oral dose of free lutein or CTA-stabilized lutein emulsion. The emulsion group exhibited a significantly higher lutein bioavailability, as evidenced by pharmacokinetic parameters derived from the serum lutein kinetic curve. In two chronic dosing studies, compared to free lutein, daily consumption of lutein emulsion for 14 days in neonatal rats resulted in a significantly higher lutein concentration in the serum and several key organs, including the liver, eye, brain, and spleen.In conclusion, a safe and efficient delivery system for lutein, i.e., the biopolymer-based lutein emulsion, was successfully developed and was shown to improve the bioavailability and tissue status of lutein in neonatal rats. It has great potential to be considered as a carrier for lutein to benefit the health of newborns.