The aim of this work is to develop a novel approach to control the growth of food-borne and food-spoilage microorganisms while reducing the use of synthetic preservatives. Bioactive food-preserving systems are based on the use of a natural antimicrobial agent loaded in a carrier material, which is able to trigger its release once necessary and to control the rate of release, thereby exerting either lethal or inhibitory effects against food pathogens or spoilage microorganisms. In this study the Schiff base of chitosan was synthesized by the reaction with cinnamaldehyde at different concentrations (0,1%, 0,25%, 0,5% w/w of dry polymer). Cinnamaldehyde is an aromatic α,β-unsaturated aldehyde, and the major component in essential oils from some cinnamon species. It has been shown to exert antimicrobial activity against a wide range of microorganisms including bacteria, yeasts, and mould. The formation of the Schiff base is reversible under suitable conditions, and this might allow the release of the active cinnamaldehyde from chitosan, used as the carrier. The reaction kinetics was investigated by means of rheological analyses, while Fourier transform infrared spectroscopy (FTIR) was used to assess the efficacy of the functionalization. The results from FT-IR spectra highlighted the presence of the absorption peak of the Schiff base, which confirmed the reactivity of the nitrogen from amino group of chitosan and carbonyl carbon of the aldehyde to form imine. Moreover, the reaction rate was found to increase as higher percentages of cinnamaldehyde were used. Cinnamaldehyde-functionalized chitosan films were then prepared and tested for contact angle and antifungal properties in vitro. The envisaged application of the films for food packaging was also tested, by placing the films in direct contact with slices of bread. It was demonstrated that the cinnamaldehyde-functionalized chitosan films increased the shelf life of the product.
Synthesis, characterization and antibacterial activity of chitosan-cinnamaldehyde derivatives
MADAGHIELE, Marta;DEMITRI, CHRISTIAN;SANNINO, Alessandro
2014-01-01
Abstract
The aim of this work is to develop a novel approach to control the growth of food-borne and food-spoilage microorganisms while reducing the use of synthetic preservatives. Bioactive food-preserving systems are based on the use of a natural antimicrobial agent loaded in a carrier material, which is able to trigger its release once necessary and to control the rate of release, thereby exerting either lethal or inhibitory effects against food pathogens or spoilage microorganisms. In this study the Schiff base of chitosan was synthesized by the reaction with cinnamaldehyde at different concentrations (0,1%, 0,25%, 0,5% w/w of dry polymer). Cinnamaldehyde is an aromatic α,β-unsaturated aldehyde, and the major component in essential oils from some cinnamon species. It has been shown to exert antimicrobial activity against a wide range of microorganisms including bacteria, yeasts, and mould. The formation of the Schiff base is reversible under suitable conditions, and this might allow the release of the active cinnamaldehyde from chitosan, used as the carrier. The reaction kinetics was investigated by means of rheological analyses, while Fourier transform infrared spectroscopy (FTIR) was used to assess the efficacy of the functionalization. The results from FT-IR spectra highlighted the presence of the absorption peak of the Schiff base, which confirmed the reactivity of the nitrogen from amino group of chitosan and carbonyl carbon of the aldehyde to form imine. Moreover, the reaction rate was found to increase as higher percentages of cinnamaldehyde were used. Cinnamaldehyde-functionalized chitosan films were then prepared and tested for contact angle and antifungal properties in vitro. The envisaged application of the films for food packaging was also tested, by placing the films in direct contact with slices of bread. It was demonstrated that the cinnamaldehyde-functionalized chitosan films increased the shelf life of the product.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
