Sugar-responsive packaging system combined with zein nanoparticle-enhanced coacervates for controlled release of...

Food spoilage contributes significantly to global food waste, while concerns over the health risks of traditional chemical preservatives have accelerated the search for natural alternatives. Tea polyphenols (TP) are natural antioxidants with antibacterial effects. However, their poor stability leads to oxidation and degradation, reducing their functional activity. To address this challenge, we developed a sustainable smart packaging system using liquid-liquid phase separation to encapsulate TP in composite coacervates formed by poly-ε-lysine (ε-PL) and ATP. Glucose oxidase (Gox) was incorporated to enable glucose-triggered, pH-responsive release of TP and ε-PL. Tannic acid-modified zein nanoparticles were self-assembled onto the surface to improve coacervate stability and enhance antibacterial and antioxidant performance. The system showed strong in vitro antioxidant activity (DPPH scavenging >90 %) and antibacterial efficacy (> 95 % reduction of Staphylococcus aureus and Escherichia coli). In banana preservation tests, it effectively delayed browning and preserved fruit color and texture. This work offers a new strategy for developing natural and environmentally responsive food preservation systems.