Preparation and characterization of hybrid polymeric coating films of chitosan–clay loaded with açaí extract (Euterpe oleracea) for application in food and pharmaceutical areas

Abstract

This study aimed to study the interaction between two different açaí extracts used insynthesis of hybrid polymeric films based on chitosan-clay and evaluate itsmorphological and physical-chemical properties, indeed antibacterial and antioxidantactivities. Films with acidified açai extract (FEAA) and non-acidified açai extract(FEBANA) were prepared using the casting method. It was possible to observe a surfacewith a rough appearance, varying according to the added extract concentration using SEMphotomicrographs. The reflection peaks were similar to the Chit-Clay film (2θ =14° and16.8°) and the reduction in the degree of chitosan crystallinity for the FEBANA films inrelation to FEAA films. The TG data also shows that the FEBANA films have a higherpercentage of water of hydration than the FEAA films, corroborating this state of anhydrous films for FEAA and state of hydrated films for FEBANA. The FEBANA filmswere two stretches in the region between 842 and 962 cm-1 and a shoulder 1095 cm-1covered by bands 1025cm-1 (Si-O-Si) and can attributed to the PEG plasticizer. Thisgreater detection of PEG stretches in the FEBANA films suggests a greater concentrationof PEG on the surface of the FEBANA film. MIC microbiology demonstrated that bothtypes of extracts were capable of inhibiting Gram (-) strains, Escherichia coli andPseudomonas aeruginosa, and Gram (+) strains, Staphylococcus aureus andStaphylococcus epidermidis. In disk diffusion, the acidified extract showed inhibitionactivity for Edwardsiella tarda, Enterococcus faecium and Streptococcus pyogenes. Bothextracts are effective in inhibiting the growth of both Gram (-) and Gram (+) bacteria.The FEAA polymeric films showed a higher degree of recovery, reversible chemicalbonding with the matrices and consequently greater DPPH free radical scavengingcapacity compared to the FEBANA polymeric films. The FEAA and FEBANA filmspresent characteristics of releasing active ingredients from the hybrid polymeric film andcan be applied in edible packaging or use in biodegradable smart packaging or as foodbiopreservative; or even, in pharmaceutical release systems for releasing activeingredients onto the skin, as organic active ingredient release membranes for skin healthand beauty, wound healing or even as adjuvants in tissue bioengineering for skinreconstruction after burns and in plastic skin surgery as biodegradable films.