Preparation and Characterization of Carboxymethyl Cellulose-Based Bioactive Composite Films Modified with Fungal Melanin and Carvacrol

Abstract

Preparation of biodegradable packaging materials and valorisation of food industry residues to achieve “zero waste” goals is still a major challenge. Herein, biopolymer-based (carboxymethyl cellulose—CMC) bioactive films were prepared by the addition, alone or in combination, of carvacrol and fungal melanin isolated from champignon mushroom (Agaricus bisporus) agro-industrial residues. The mechanical, optical, thermal, water vapour, and UV-Vis barrier properties were studied. Fourier-transform infrared (FT-IR) spectroscopy studies were carried out to analyse the chemical composition of the resulting films. Antibacterial, antifungal, and antioxidant activities were also determined. Both CMC/melanin and CMC/melanin/carvacrol films showed some antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans. The addition of melanin increased the UV-blocking, mechanical, water vapour barrier, and antioxidant properties without substantially reducing the transparency of the films. The addition of carvacrol caused loss of transparency, however, composite CMC/melanin/carvacrol films showed excellent antioxidant activity and enhanced mechanical strength. The developed bioactive biopolymer films have a good potential to be green bioactive alternatives to plastic films in food packaging applications.

Development and Characterization of Bioactive Poly(butylene-succinate) Films Modified with Quercetin for Food Packaging Applications

“…Gravimetricaly methodology was used for determination of the water vapor transmission rate (WVTR) of films, applying the procedure described in a previous study [ 25 ]. Initially, the amount of dry CaCl 2 inside the container was 9 g. The area of film samples was 8.86 cm 2 .…”

“…To determine moisture content (MC) of the films, the samples were dried at 65 °C for 24 h, and the weight change was analyzed [ 25 ]. For moisture sorption (MS) and water sorption (WS), PBS-based films samples 20 mm × 20 mm were prepared.…”

“…Samples were analyzed in 10 repetitions, taken at random locations on each of the studied films. The total color difference (Δ E ), yellowness index ( YI ) and chroma ( C ) were calculated according the following formulas [ 25 ]: …”

“…Antixodiant activity (as a capacity to scavenge free radicals—DPPH, ABTS and O 2 − ) and reducing power of PBS-based films were determined by using spectroscopic methods according to the procedures described elsewhere [ 25 ]. The DPPH radical scavenging activity was determined by placing 100 mg of each film in 25 mL of 0.01 mM DPPH methanolic solution, incubated for 30 min at room temperature.…”

“…There is much interest among food manufacturers in using natural antioxidants as replacements for the synthetic antioxidants that are currently being used. Moreover, the addition of active agents in the polymeric matrix can affect the mechanical, thermal, optical and gas barrier properties of the packaging materials [ 9 , 20 , 23 , 25 , 26 ]. A wide spectrum of additives (nano or microsized) has been used for the preparation of active films [ 1 , 2 , 12 ].…”