Application of chitosan films incorporated with Zanthoxylum limonella essential oil for extending shelf life of pork.

This study aimed to produce chitosan films incorporated with Zanthoxylum limonella essential oil for extending shelf life. The volatile compounds of Z. limonella essential oil were identified by gas chromatography-mass spectrometry consisting of limonene, α-phellandrene, ρ-cymene, and sabinene as major compounds. In this study, the addition of Z. limonella essential oil at concentrations of 0 %, 2 %, and 4 % in chitosan film was assessed for its antibacterial activity against Escherichia coli and Staphylococcus aureus. Chitosan film incorporated with 4 % essential oil demonstrated the most significant antibacterial effect against E. coli and S. aureus in comparison to the chitosan film without essential oil due to the synergistic effects on antibacterial activity. The physical and mechanical properties of the chitosan films incorporated with Z. limonella oil developed were also assessed. The addition of essential oil to chitosan films led to improvements in mechanical strength and flexibility, while minimal changes were observed in terms of water solubility, water vapor permeability, and thermal stability. The findings emphasize that this innovative film not only extends the shelf life of pork without chemical preservatives but is also a fully bio-based material. Consequently, it shows great potential to be used as active packaging within the food industry.

Review of the recent developments in all-cellulose nanocomposites: Properties and applications.

Cellulose, the most abundant polysaccharide on Earth, has a number of desirable properties, including availability, biodegradability, low cost, and low toxicity and has been used in a variety of applications. Recently, all-cellulose composite materials have been made from a wide variety of cellulose sources, including wood and agricultural wastes, via impregnation or partial surface dissolution approaches utilizing a specific solvent. Due to the improved interfacial interactions between the cellulose matrix and cellulose reinforcement, all-cellulose composites exhibit superior mechanical properties when compared to biopolymers and petroleum-based polymers. The current article discusses the factors affecting the mechanical properties and interfacial bonding of all-cellulose composites. Additionally, the incorporation of inorganic nanoparticles is described to enhance the multi-functional properties of all-cellulose composites, such as their conductivity, permeability, and adsorption. Furthermore, this review summarizes the potential applications of all-cellulose composites in the following areas: composites, packaging, aerogels, hydrogels, fibers, tissue engineering, membranes, textiles, and coatings.

Investigation into the structural, morphological, mechanical and thermal behaviour of bacterial cellulose after a two-step purification process.

Bacterial cellulose (BC) is a natural hydrogel, which is produced by Acetobacter xylinum (recently renamed Gluconacetobacter xylinum) in culture and constitutes of a three-dimensional network of ribbon-shaped bundles of cellulose microfibrils. Here, a two-step purification process is presented that significantly improves the structural, mechanical, thermal and morphological behaviour of BC sheet processed from these hydrogels produced in static culture. Alkalisation of BC using a single-step treatment of 2.5 wt.% NaOH solution produced a twofold increase in Young's modulus of processed BC sheet over untreated BC sheet. Further enhancements are achieved after a second treatment with 2.5 wt.% NaOCl (bleaching). These treatments were carefully designed in order to prevent any polymorphic crystal transformation from cellulose I to cellulose II, which can be detrimental for the mechanical properties. Scanning electron microscopy and thermogravimetric analysis reveals that with increasing chemical treatment, morphological and thermal stability of the processed films are also improved.

All-aramid composites by partial fiber dissolution.

The area of self-reinforced polymer composites is one of the fastest growing areas in engineering polymers, but until now these materials have been mainly developed on the basis of thermoplastic fibers of moderate performance. In this work, we report on a new type of self-reinforced composites based on high-performance aramid fibers to produce an "all-aramid" composite by applying a surface-dissolution method to fuse poly(p-phenylene terephthalamide) (PPTA) fibers together. After immersion in concentrated (95%) sulphuric acid (H(2)SO(4)) for a selected period of time, partially dissolved fiber surfaces were converted into a PPTA interphase or matrix phase. Following extraction of H(2)SO(4) and drying, a consolidated all-aramid composite was formed. The structure, mechanical- and thermal properties of these single-polymer composites were investigated. Optimum processing conditions resulted in unidirectional composites of high reinforcement content (approximately 75 vol %) and good interfacial bonding. The all-aramid composites featured a Young's modulus of approximately 65 GPa at room temperature, and a tensile strength of 1.4 GPa, which are comparable with or exceed the corresponding values of conventional aramid/epoxy composites. However, since fiber, matrix and interphase in all-aramid composites are based on the same high-temperature resistant PPTA polymer, a high modulus of approximately 50 GPa was maintained up to 250 degrees C, demonstrating the potential of these materials for high-temperature applications.