Soybean protein complexes as diglyceride nanostructured lipid carriers for lycopene delivery: preparation via...

Lycopene (LYC), a potent lipophilic antioxidant, faces significant limitations in functional food applications due to its poor chemical stability and low bioaccessibility. To address these challenges, we developed a novel nanostructured lipid carrier (NLC) system stabilized by metal-phenol network (MPN)-coated soybean protein isolate (SPI) nanoparticles. Multiple characterizations confirmed the synergistic formation of SPI-tannic acid (TA)-Fe³⁺ nanoparticles (ST-Fe NPs) through metal-phenol coordination and covalent bonding. Interfacial rheology indicates ST-Fe NPs effectively reduce surface tension and form boundary films at oil-water interfaces. The MPN coating not only enhances the stability of lycopene during long-term storage and thermal processing, but also provides excellent protection for lycopene, significantly improving its bioaccessibility during in vitro digestion (up to 31.2%)-more than double that of a pure protein-stabilized NLC system (13.1%). This study reveals the immense potential of MPN-based interfacial engineering technology in designing advanced food-grade lipid carriers for the precise delivery of sensitive bioactive compounds.