Reducing pesticide residues and postharvest losses through appropiata washing solutions

The safety and quality of fresh produce are increasingly threatened by pesticide residues and postharvest losses, while conventional washing and preservation methods show limited effectiveness and may introduce new contaminants.

This thesis develops and evaluates multifunctional, biodegradable systems based on metal–phenolic networks (MPN) combined with starch nanoparticles (SNPs) to address these dual challenges.

A novel dual-action postharvest wash, formed by self-assembly of tannic acid and iron ions onto SNPs (FTN@SNPs), was designed to remove pesticide residues while providing antimicrobial and antioxidant protection.

Experimental studies demonstrated that FTN@SNPs removed over 86% of diverse surface pesticides, including imidacloprid, acetamiprid, and thiabendazole, significantly outperforming conventional washing.

Surface-enhanced Raman spectroscopy (SERS) quantified removal efficiency, while molecular dynamics simulations revealed that adsorption was formed by π–π interactions, van der Waals forces, and hydrogen bonding, with binding energies correlating to experimental results.

In addition, the coating extended shelf life and maintained key quality attributes of apples and grapes by reducing weight loss, preserving firmness, and protecting antioxidant content.

Comparative studies of Fe-tannic acid-MPN-capped starch nanoparticles (Fe-TA-MCS) and Zn-epigallocatechin gallate MPN-capped starch nanoparticles (Zn-EGCG-MCS) formulations further highlighted the tunability of MPN–SNP systems, with Fe-TA-MCS enhancing firmness and antimicrobial activity, and Zn-EGCG-MCS preserving color, acidity, and phenolic content.

The findings demonstrate that MPN-based coatings and washing agents provide a green, cost-effective, and sustainable strategy for simultaneously addressing two critical challenges in the fresh produce supply chain: food safety and postharvest quality losses.

Sources

Multifunctional washing solutions for reducing pesticide residues and postharvest losses in fresh produce
Jin, Tianyi (2025)
University of British Columbia (UBC) Library
https://open.library.ubc.ca/soa/cIRcle/collections/ubctheses/24/items/1.0450518
https://dx.doi.org/10.14288/1.0450518

The picture is shows an apple packaging line by UNITEC