The antifungal, antibacterial, and antioxidant activity of four commercial essential oils (EOs) (thyme, clove, rosemary, and tea tree) from Romanian production were studied in order to assess them as bioactive compounds for active food packaging applications. The chemical composition of the oils was determined with the Folin–Ciocâlteu method and gas chromatography coupled with mass spectrometry and flame ionization detectors, and it was found that they respect the AFNOR/ISO standard limits. The EOs were tested against three food spoilage fungi—Fusarium graminearum, Penicillium corylophilum, and Aspergillus brasiliensis—and three potential pathogenic food bacteria—Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes—using the disc diffusion method. It was found that the EOs of thyme, clove, and tea tree can be used as antimicrobial agents against the tested fungi and bacteria, thyme having the highest inhibitory effect. Concerning antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) methods, it has been established that the clove oil exhibits the highest activity because of its high phenolic content. Promising results were obtained by their incorporation into chitosan emulsions and films, which show potential for food packaging. Therefore, these essential oils could be suitable alternatives to chemical additives, satisfying the consumer demand for naturally preserved food products ensuring its safety.
In the latest years, researchers have been working to reduce the dependence on petroleum based fuels and products due to the increase in environmental consciousness. This leads to investigate the environmentally friendly sustainable materials in order to replace the existing ones. One of these polymeric materials is poly(3-hydroxybutyrate) (PHB) which is a semi-crystalline, linear polymer belonging to the class of polyhydroxyalkanoates. It is fully biodegradable and biocompatible, and produced from renewable resources. Although having promising properties, PHB is unstable during processing at elevated temperatures causing thermal degradation that reduces its mechanical performance. The purpose of the present study was to develop and characterize new composite materials based on PHB and different percentage of cellulose fibers (from 2% to 10%), in order to improve PHB's physical mechanical behavior. In this respect, a series of physical-mechanical analyses (melt processing, optical properties, differential scanning calorimetry, water vapor permeability, etc.) were performed. The results obtained during this study show the most appropriate composition of the tested mixtures and demonstrate that the polymeric material based on PHB and cellulose fibers have good physical -mechanical characteristics, being suitable for packaging industry.
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