Astaxanthin-zein-polysaccharide nanoparticles via intelligent microfluidics: Ionic-type polysaccharides differentially regulate stability and intestinal sustained release.

Astaxanthin (AST), a potent lipophilic antioxidant, suffers from poor water solubility, environmental instability and low bioavailability, severely restricting its application in functional foods. In this study, six AST-Zein-polysaccharide ternary nanoparticles were precisely fabricated via an advancedcomputer-integrated intelligently controlled microfluidic platform. Different from conventional thermal bulk methods, this non-thermal microfluidic technique achieves confined self-assembly and precise laminar mixing for efficient, reproducible fabrication of homogeneous nanoparticles. Six food-grade polysaccharides (gum arabic (GA), pectin, HPMC, chitosan, guar gum, and xanthan gum) were systematically compared, and AST-GA-NPs were screened as the optimal delivery system. These nanoparticles exhibited superior comprehensive performance with a small particle size (80.8 ± 2.6 nm), low PDI (0.116 ± 0.054), and excellent antioxidant activity (DPPH: 87.17 ± 1.13%; ABTS: 90.51 ± 1.76%), as well as good morphological regularity, hydrophilicity and stability under variable pH, salt and light conditions. Gastrointestinal simulation tests showed that the cumulative AST release rate of AST-GA-NPs reached 86.62 ± 0.39%, 7.94 times higher than that of free AST. Multispectral analysis verified that hydrogen bonding and hydrophobic interactions drove the stable self-assembly of nanoparticles. The unique highly branched structure and anionic characteristic of GA further optimized the interfacial characteristics and structural stability of the ternary system. This study proves the great superiority of computer-integrated microfluidics in constructing high-performance bioactive delivery systems, providing a feasible strategy for improving the stability and intestinal bioavailability of AST in functional foods.