Assessment of antibacterial and antioxidant properties of chitosan edible films incorporated with maqui berry (Aristotelia chilensis)

Abstract

The purpose of this work was to evaluate chitosan edible films (CH) incorporated with maqui berry extracts (MB) for (i) the inhibition growth of some bacterial strains (ii) their total phenolic (TPC) and total flavonoid content and (iii) their antioxidant activity to define if the chitosan edible films incorporated with maqui berry extract (CH + MB) could be used as natural active films for food use. The antioxidant activity was determined with three different analytical assays: DPPH radical scavenging ability assay, Ferrous chelating capacity (FIC) and ferric reducing activity power (FRAP). The agar disc diffusion method was used to determine the antibacterial activity against Listeria innocua, Serratia marcescens, Aeromonas hydrophila, Achromobacter denitrificans, Alcaligenes faecalis, Pseudomonas fluorescens, Citrobacter freundii and Shewanella putrefaciens. CH + MB showed higher antioxidant activity, at all concentrations (0.5 and 1%) and with all methods assayed than CH. Furthermore, the antioxidant activity of CH + MB occurs in a concentration-dependent manner. Regarding the antimicrobial activity, CH + MB were effective against seven of the eight tested bacteria. This antibacterial activity takes place in a concentration-dependent manner. CH were not active, against six of the eight bacteria strain tested. CH + MB could improve the quality of foods due to delay the oxidation and the microbial growth.