Ultrasound-assisted assembly of Auricularia auricula-judae polysaccharide–soy protein isolate nanoparticles: The effect of extraction methods on functional properties

Abstract

This study compared the emulsifying properties and in vitro anti-inflammatory activity of black fungus polysaccharides (AAP) extracted by ultra-high-pressure-assisted extraction (UHP) and hot water extraction (HWE). UHP-AAP exhibited improved emulsifying performance, with an emulsifying activity index (EAI) of 0.62 m2/g and emulsifying stability index (ESI) of 79.85 min, together with enhanced anti-inflammatory activity. Using UHP-AAP and soy protein isolate (SPI), composite nanoparticles (A-S NPs) were fabricated via ultrasound-assisted self-assembly. The optimized A-S NPs (AAP/SPI = 1:1, 300 W, 10 min) showed a particle size of 318 nm, a ζ-potential of −43 mV, and a PDI of 0.2136. Hydrogen bonding, electrostatic attraction, and hydrophobic interactions promoted molecular rearrangement and network formation, improving colloidal and thermal stability. These nanoparticles possess good thermal stability and dispersibility, making them suitable as functional food carriers.