Development and application of dialdehyde starch-grafted ε-polylysine copolymers as eco-friendly fruit detergents

Chemical detergents are extensively used to remove pesticide residues and foodborne pathogens on fresh fruits, but their residues are toxic to humans. To address this issue, a dual-functional starch copolymer, specifically dialdehyde starch-grafted ε-polylysine copolymer (DIA-ε-PL starch), was synthesized utilizing native starch with surfactant properties and the natural antimicrobial cationic peptide ε-polylysine (ε-PL). The effectiveness of DIA-ε-PL starch as a fruit detergent was subsequently evaluated. Raman imaging and HPLC results indicated that the removal efficiency of chlorothalonil (CHT) reached 96.62% under the optimal conditions which involved washing apples with a 1% corn-DIA-0.16-ε-PL solution at 30°C for 15 min. Compared to traditional washing reagents, DIA-ε-PL starch not only exhibited higher CHT removal efficiency without migrating into apple tissues but also demonstrated superior antibacterial effect against S. aureus (94.64%) and E. coli (98.78%). The DIA-ε-PL starch exhibits significant potential as a fruit-specific detergent due to its non-toxicity, economy, sustainability, and eco-friendliness.