Tannic acid one-step induced quaternized chitin-based edible and easy-cleaning coatings with multifunctional preservation for perishable products

Abstract

The development of biomass hydrogel coatings is significant for fruit preservation. This paper presents the facile development of a multifunctional polysaccharide-based hydrogel produced from quaternized chitin (QC) and tannic acid (TA) by in situ rapid cross-linking with high-density hydrogen bonding using the sample mixing method. The Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectra, and thermogravimetric analysis (TGA) proved that QC-TA hydrogel was formed by physical interactions (hydrogen bonding, electrostatic interaction, etc.). Moreover, the cross-linking density of the QC-TA hydrogels was analyzed by rheological property measurements and scanning electron microscope (SEM) morphology observations. This polysaccharide-based hydrogel, QC-TA, was evaluated as an edible coating for perishable food items, demonstrating significant improvements in physic-chemical properties, oxidation resistance, and antimicrobial activity against key pathogens (E. coli, S. aureus, and C. albicans). Notably, the hydrogel formed a protective film that effectively shields fruits from mechanical damage, maintaining freshness and extending shelf life, and also featuring with easy cleaning. Applied to cherry tomatoes, the QC-TA coating ensured a smooth, uniform surface, reducing dehydration and flavor loss while inhibiting microbial growth. These findings underscore the potential of employing polyphenol induced polysaccharide forming green hydrogel coatings as an economical, efficient strategy for enhancing the quality and safety of perishable foods, representing an advancement in the field of sustainable food packaging.