Novel Carvacrol@activated Carbon Nanohybrid for Innovative Poly(lactide Acid)/Triethyl Citrate Based Sustainable Active Packaging Films

It has been well known for the past decade that the accumulation of food E-preservatives in the human body has harmful consequences for human health. Furthermore, scientists have realized that despite the convenience offered by petrochemical-derived polymers, a circular economy and sustainability are two current necessities; thus, the use of biodegradable alternative materials is imposed. The food packaging sector is one of the most rapidly changing sectors in the world. In recent years, many studies have focused on the development of active packaging films to replace old non-ecofriendly techniques with novel environmentally friendly methods. In this study, a novel self-healable, biodegradable active packaging film was developed using poly(lactic acid) (PLA) as a biopolymer, which was incorporated with a nanohybrid solid material as a natural preservative. This nanohybrid was derived via the absorption of carvacrol (CV) essential oil in an activated carbon (AC) nanocarrier. A material with a high carvacrol load of 71.3%wt. into AC via a vacuum-assisted adsorption method, functioning as a natural antioxidant and an antibacterial agent. The CV@AC nanohybrid was successfully dispersed in a PLA/triethyl citrate (TEC) matrix via melt extrusion, and a final PLA/TEC/xCV@AC nanocomposite film was developed. The study concluded that x = 10%wt. CV@AC was the optimum nanohybrid amount incorporated in the self-healable PLA/TEC and exhibited 277% higher ultimate strength and 72% higher water barrier compared to the pure PLA/TEC. Moreover, it remained ductile enough to show the slowest CV release rate, highest antioxidant activity, and significant antibacterial activity against <i>Staphylococcus aureus</i> and <i>Salmonella enterica</i> ssp. <i>enterica serovar Typhimurium</i>. This film extended the shelf life of fresh minced pork by four days, according to total viable count measurements, and decreased its lipid oxidation rate. Finally, this novel film preserved the nutritional value of porkby maintaining a higher heme iron content and showed a higher level of sensory characteristics compared to commercial packaging paper.