Chitosan films as pH-responsive sustained release systems of naturally occurring antifungal volatile compounds

Reversible imine bonds have been used as a strategy to develop pH-dependent antifungal systems based on grafting benzaldehyde and citral onto the surface of chitosan films. Formation of imine bonds was confirmed by ATR-FTIR and XPS. Aldehyde unit incorporation respect to glucosamine units of chitosan polymer was estimated by elemental analysis. The rate and extent of imine bond hydrolysis depended on the pH of the media and the chemical structure of the aldehyde. The release of the aldehydes was monitored by gas chromatography observing acidic media favours the release. Imine bond obtained from benzaldehyde was more prone to be hydrolysed than citral. Chitosan films grafted with benzaldehyde and triggered at acidic pH controlled in vitro growth of common fruit and vegetable spoilage and pathogenic fungi. The films developed could be applied in the design of food packages intended to prevent postharvest fungal spoilage.

Automated summary

Reversible imine bonds were used to develop pH-dependent antifungal systems by grafting benzaldehyde and citral onto chitosan films. The formation of imine bonds was confirmed, and the incorporation of aldehyde units into the chitosan polymer was estimated. The study found that acidic media favored the release of aldehydes, with imine bonds from benzaldehyde being more prone to hydrolysis.