Mechanism of color change in Antarctic krill oil during storage

Antarctic krill oil (AKO) is reddish-orange in color but undergoes changes during storage. To investigate the color deterioration and potential mechanisms involved, the changes in color, endogenous components (astaxanthin, fatty acids, and phospholipids), and reaction products (aldehydes, α-dicarbonyl compounds, and pyrroles) of AKO upon storage were determined. Although the visual color of AKO tended to darken upon storage, the colorimetric analysis and ultraviolet-visible spectrum analysis both indicated a fading in red and yellow due to the oxidative degradation of astaxanthin. During storage of AKO, lipid oxidation led to the formation of carbonyl compounds such as aldehydes and α-dicarbonyls. In addition, phosphatidylethanolamines (PEs) exhibited a faster loss rate than phosphatidylcholines. Moreover, hydrophobic pyrroles, the Maillard-like reaction products associated with primary amine groups in PEs accumulated. Therefore, it is suggested that the Maillard-like reaction between PEs and carbonyl compounds formed by lipid oxidation contributed to color darkening of AKO during storage.

Orally administered dual-targeted astaxanthin nanoparticles as novel dietary supplements for alleviating hepatocyte oxidative stress

The enhancement of bioavailability of food bioactive compounds as dietary supplements can be achieved through the development of targeted delivery systems. This study aimed to develop a novel dual-targeted delivery system for hepatocytes and mitochondria using phacoemulsification self-assembly. The delivery systems were engineered by modifying whey protein isolate (WPI) with galactose oligosaccharide (GOS) and triphenylphosphonium (TPP) to improve AXT transport to the liver and promote hepatic well-being. The dual-targeted nanoparticles (AXT@TPP-WPI-GOS) significantly reduced reactive oxygen species in in vitro experiments, thereby slowing down apoptosis. The AXT@TPP-WPI-GOS exhibited a prominent mitochondrial targeting capacity with a Pearson correlation coefficient of 0.76 at 4 h. In vivo pharmacokinetic experiments revealed that AXT@TPP-WPI-GOS could enhance AXT utilization by 28.18 ± 11.69%. Fluorescence imaging in mice demonstrated significantly higher levels of AXT@TPP-WPI-GOS accumulation in the liver compared to that of free AXT. Therefore, these nanoparticles hold promising applications in nutrient fortification, improving the bioavailability of AXT and supporting hepatic well-being.