Antimicrobial and antioxidant properties of chitosan-based viscose fibres enzymatically functionalized with flavonoids

Abstract

The main purpose of this research was to qualitatively and quantitatively identify chitosan-based viscose fibre functional group surfaces as modified by two chemically-similar phenolics, namely fisetin and quercetin. Potentiometric titration was used to determine fibre-dissociable weak acids as a consequence of the presence of chitosan and deposited flavonoids. In addition, a conventional spectrophotometric method using C.I. Acid Orange 7 dye was used for determining the amino groups only. Finally, the antioxidant and antimicrobial properties of the fibres were evaluated, respectively. It has been clearly shown that the introduction of flavonoid onto the fibres introduces a significant amount of anionic phenolic hydroxyl groups, leading to fibre antioxidant activity and a decrease in fibre antimicrobial efficiency.

Physicochemical Characterization of Packaging Foils Coated by Chitosan and Polyphenols Colloidal Formulations

“…For all samples coated with a bilayer of chitosan and chitosan nanoparticles with embedded extracts, the shift of the isoelectric point to lower pH occurred due to the introduction of the acidic character of the extracts and the partly/blocking of amino groups by the chemical reaction of extracts (polyphenols) with chitosan. It was shown in our previous work that the attachment of antioxidants onto chitosan fibres blocked accessible chitosan amino groups, due to a pronounced interaction between these amino groups with the OH groups of flavonoids [27]. Similar interactions between amino groups of chitosan and phenolic groups of extracts may have occurred here.…”

“…This is especially important, in order to follow the protonation behavior of chitosan amino groups and the dissociation of phenolic groups, which create the antimicrobial and antioxidant activity at the foil surface. It is known that protonated amino groups are responsible for the antimicrobial activity of chitosan [25,26], whilst the dissociation degree of phenolic groups influences the antioxidant activity [27]. Considering the final application of the chitosan-polyphenol functionalized PP and PE foils as packaging materials, it is of paramount importance to understand their surface properties better, and, consequently, their response in a given environment.…”

Electrokinetic properties of fibres functionalised by chitosan and chitosan nanoparticles

“…The pH of the fibres' coating procedure does not seem to influence the resultant antimicrobial activity of fibres, whereas electrokinetical properties of fibres treated at pH 7 indicated higher amount of TMC was introduced on the fibres. These results again imply that mechanism of chitosan's (Fras-Zemljic et al 2011) In general, the microorganisms' inhibition, achieved by TMC-coated fibres (Table 5), is lower compared to the fibres treated with CS (Table 4). These results are opposing to the ones previously published, reporting the stronger activity of TMC compared to CS (Sadeghi et al 2008;Xu et al 2010).…”

Development of Biodegradable Whey-Based Laminate Functionalised by Chitosan–Natural Extract Formulations

“…When calculated into mg, the desorbed amount in relation to the dm 2 of the laminate migration profile was in accordance with the required overall migration limit (OML) of a compound of surfaces, which according to the guidelines on (European Union (EU)) 10/2011 [40] must be less than 10 mg/dm 2 or 60 mg/kg food. For each coating applied to a whey-based laminate film, extracts must be loaded more successfully (in higher concentrations) into chitosan nanodispersion to obtain an even higher antioxidant capacity, while chitosan itself has relatively poor antioxidant properties [54]. A higher concentration of the extracts can be helpful to achieve an efficiency of around 90%.…”