Characterization of citric acid-crosslinked chitosan and hydroxypropyl methylcellulose blended film for coating Cavendish bananas.

This study aimed to characterize a novel film material based on citric acid-crosslinked chitosan blended with hydroxypropyl methylcellulose (HPMC) in various ratios, and to investigate the physiological effects of coating on the quality of Cavendish bananas. The physical, chemical, and mechanical properties of the various ratios of blended films were evaluated. The appropriate formulation was applied for coating Cavendish banana, and its physiological impacts on respiration rate, weight loss, textural changes, color variations, and total soluble solids were monitored over a 14-day period. FTIR analysis confirmed the successful cross-linking of chitosan with citric acid, forming a CO group on the amine group, and its blend with HPMC formed intermolecular hydrogen bonds. The higher ratio of cross-linked chitosan over 50 % increased WCA and reduced WVTR by 40 %, exhibiting better barrier properties and wettability for coating. The film with a higher content of cross-linked chitosan (75 % and 100 %) had better moisture retention, flexibility, and transparency properties. The coating effectively slowed respiration rate by decreasing oxygen intake, increasing CO production, and delaying ethylene production to reach its peak before the senescence phase. The results eventually induced a reduction in weight loss and a delay in the softening process and TSS changes. In terms of the hue angle, the color changes of the coated banana were also 0.50° slower for each day than those of the uncoated banana. The shelf life of the banana was quantitatively estimated, and the coating could enhance the post-harvest life of the bananas for approximately four days.