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Food packaging plays a critical role in maintaining the freshness and quality of foods by minimizing oxidation and microbial contamination. Active packaging systems based on biodegradable polymers with green production have received great attention. Here, Melissa officinalis extract (ME) with antimicrobial and antioxidant properties was incorporated into chitosan (Cs)/ polyethylene oxide (PEO) electrospun nanofibers. Nanofibers were fabricated through electrospinning as an efficient and versatile technique with an applied voltage of 18 kV and a tip-to-collector distance of 18 cm. The total phenolic and flavonoid content of ME was measured. By incorporating ME into the nanofibers, the need for synthetic additives or preservatives can be reduced, promoting eco-friendly packaging solutions. The nanofibers were characterized regarding morphology, water contact angle, swelling degree, weight loss, mechanical strength, and vapor permeability. To improve the mechanical properties of nanofibers, photo-cross-linking was applied with benzophenone. Nanofibers were evaluated in terms of antioxidant and antifungal activities as well as their ability to protect edible mushroom quality. ME contained a significant amount of phenolic compounds as well as 1.3 mg caffeic acid/g herbal extract. Cs/PEO/ME nanofibers showed uniform and bead-free structures with an average fiber diameter of 157.7 nm. Photo-cross-linked nanofibers exhibited higher water resistance and mechanical properties compared with the as-spun formulation. ME-loaded nanofibers had higher antioxidant and antifungal activities than the empty formulation. Cross-linked Cs/PEO/ME nanofibers prolonged the shelf life of mushrooms compared to empty mats and plastic films. In conclusion, the multifunctional cross-linked Cs/PEO/ME nanofibers have broad prospects in active food packaging applications. [ABSTRACT FROM AUTHOR]

The production of biodegradable food packaging has gained a great deal of attention due to the environmental concerns associated with the accumulation of plastic waste. In this study, chitosan (Cs)/gelatin (Gel) nanofibers (NFs) containing Zataria multiflora extract (ZME) were prepared through the electrospinning technique. Morphological characteristics of NFs were determined by scanning electron microscopy (SEM). NFs were cross-linked via a green process using citric acid and heat treatment. The effect of NF cross-linking on the structure, water stability, and mechanical behavior of the scaffolds was investigated. The antibacterial effectiveness of the prepared mats was studied by the colony counting method. In addition, the scaffolds were applied in the preservation of edible mushrooms. SEM analysis revealed smooth and bead-free Gel70-Cs30-ZME NFs with an average diameter of 188 nm. Cross-linked NFs possessed higher water contact angle (0° vs. 65.9°), swelling degree (45% vs. 1079%), and mechanical properties (tensile strength of 0.14 MPa vs. 0.45 MPa) than as-spun mats. Weight loss and water vapor permeability were reduced after cross-linking from 96 to 34% and from 6.7 to 5.2 g mm/kPa h m2, respectively. Cross-linked Gel70-Cs30-ZME NFs exhibited satisfactory antibacterial activity with about 3 and 2 Log CFU/mL reduction of Staphylococcus aureus and Escherichia coli populations, respectively. Electrospun mats delayed the deterioration of mushrooms in comparison with the commonly used polyethylene films. Therefore, cross-linked Gel70-Cs30-ZME scaffold with improved mechanical and functional properties has potential applications in fruit and vegetable packaging. [ABSTRACT FROM AUTHOR]

Crude oil is a kind of water/oil emulsion, which the oil phase consists of organic molecules with different molecular weights such as alkanes, paraffin, asphaltene, and resins. Due to the change in physicochemical conditions during the production, transportation, storage, and refining, heavier molecules can precipitate from crude oil. Thus, viscous sludge formed at the bottom of storage tanks can cause many problems including reduction of storage capacity of tank, oil contamination, corrosion, repair costs, environmental pollution, etc. The reduction of sludge viscosity can be achieved by reduction of its interfacial tension. In this study, different chemical and physical factors, influencing prepared emulsions (made of sludge, water and surfactant), such as surfactants, solvents, temperature, pressure, and mixing conditions were investigated. Results showed that non-ionic surfactants (like bitumen emulsifier), and solvents (such as mixed xylene, AW-400, and AW-402), injection of additives, applying pressure, and mixing operations had a positive effect on reduction of emulsion viscosity. All experiments were carried out with sludge obtained from crude oil storage tanks at Kharg Island, Iran. [ABSTRACT FROM AUTHOR]