Search Results (378)

Developing advanced functional materials requires the synergistic integration of nanoscale reinforcements with tailored properties. In this work, composite films of cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and reduced graphene oxide (rGO) were synthesized using a combination of solution casting, high shear homogenization, vacuum filtration, and environmentally friendly chemical reduction. The resulting CNC/CNF/rGO films exhibited a robust hierarchical structure with strong interfacial interactions, enabling exceptional mechanical properties, specifically a tensile strength of 215 MPa and a Young’s modulus of 18 GPa, alongside a continuous conductive network confirmed by frequency-independent electrical conductivity up to 30 kHz. Comprehensive dielectric characterization revealed frequency-dependent permittivity and low dielectric loss, aligning with Maxwell–Wagner theoretical predictions for heterogeneous composites. The composites also demonstrated thermal stability, with electrical conductivity increasing monotonically from 0 °C to 200 °C. These findings highlighted the CNC/CNF/rGO films’ suitability for applications in flexible electronics, electromagnetic shielding, packaging, and high-performance structural materials. Future optimization and modeling approaches, including fractional calculus, are recommended to further enhance multifunctionality and exploit the unique synergistic interactions intrinsic to nanocellulose–graphene oxide platforms. Full article

Fresh bluefin tuna is highly susceptible to quality deterioration during refrigerated storage due to lipid oxidation and microbial activity, creating a need for effective clean-label preservation strategies. This study evaluated the efficacy of natural astaxanthin as an antioxidant treatment to improve the refrigerated stability of fresh bluefin tuna (Thunnus thynnus) fillets stored under vacuum packaging (VP) or modified atmosphere packaging (MAP; 70% N₂/30% CO₂). Tuna fillets were treated by short immersion in astaxanthin solutions (10–20 mg/L), applied alone or in combination with other natural antioxidants, including ascorbic acid, and compared with a rosemary–ascorbic acid reference system. Selected treatments incorporated microencapsulated astaxanthin to enhance antioxidant stability. Quality changes were monitored during refrigerated storage (4 °C) through sensory evaluation (appearance, colour, and odour), total volatile basic nitrogen (TVBN), histamine determination, and microbiological analyses. Astaxanthin-treated samples exhibited improved colour stability, delayed sensory deterioration, and significantly lower TVBN accumulation compared with the rosemary–ascorbic acid reference treatment. Under MAP conditions, astaxanthin reduced TVBN values by approximately 20% after 12 days of storage, while microencapsulated astaxanthin combined with ascorbic acid achieved reductions of up to 30% under vacuum packaging. All selected treatments complied with regulatory microbiological and histamine limits throughout storage. These results indicate that natural astaxanthin, particularly in microencapsulated formulations, can enhance quality stability of fresh bluefin tuna when applied in combination with oxygen-limiting packaging systems under controlled refrigerated conditions. The findings provide a scientific basis for further investigation of astaxanthin-based preservation strategies in high-value seafood products. Full article

The antimicrobial effect of Chios mastic gum essential oil (mastic EO) was evaluated in vitro in a variety of spoilage and pathogenic bacteria and yeast strains isolated from spoiled cheeses with concentrations ranging from 0.006 to 2% (Minimum Inhibitory Concentration (MIC)) and in situ (cheese slices). The mastic EO (2%) was incorporated in sodium alginate edible gel films (Mastic Edible Films (MEFs)), and then the films were applied between the cheese slices that had been previously inoculated with a cocktail of three strains of Listeria monocytogenes (on both sides of the slices) and subjected or not to high-pressure processing (HPP). Cheese samples were vacuum-packaged and cold stored (4 °C), and microbiological, pH and organoleptic (in pathogen-free slices) analyses were employed, while Fourier Transform Infrared (FTIR) spectroscopy was applied as a rapid technique to monitor the biochemical changes present on the slices. Samples without MEF, without the pathogen and with or without HPP were employed as controls. Results showed that the MIC of the mastic EO varied from 0.01% to 1.8% depending on the species and/or strains. Pathogen’s growth was suppressed by HPP, MEF or their combination, which showed the highest efficacy. These results could provide useful data to support risk assessment studies on ready-to-eat foods. Finally, FTIR implementation with data analytics was found to be satisfactory, indicating FTIR’s potential as a reliable information source for cheese quality control. Full article

Currently, the packaging sector must continue developing more sustainable systems to reduce the high quantities of single-use plastic waste generated. This study evaluated the production and characterization of bio-based composite trays with antimicrobial activity. Different formulations of polybutylene adipate co-terephthalate (PBAT) and polylactic acid (PLA) with polyethylene glycol (PEG) as plasticizer and citric acid as a compatibilizer/crosslinker were evaluated, in addition to the inclusion of plantain microfibers (PFs), TiO₂, and menthol as reinforcing and antimicrobial agents, respectively. The mixtures were subjected to pellet extrusion (165/175/185/190 °C and 60 rpm) and then to flat sheet extrusion (at 185/190/195/205 °C and 60 rpm), besides calendering (at 3.5–6.0 rpm). A single-screw extruder was used in both cases. The obtained sheets (0.317 ± 0.040 mm thick and 17 cm wide) were molded into 12.5 × 11.0 × 3.5 cm trays in a thermoforming machine (at 325 °C and vacuum pressure). For the resulting composite sheets and trays, measurements of mechanical strength, moisture absorption, barrier (WVTR), transmittance, and color were performed. FT-IR, DSC, TGA, SEM, and in vitro antimicrobial tests were also conducted. Based on these tests, an initial formulation with an 85/15 (w/w) PLA/PBAT ratio was defined, which was then reinforced with 3% (w/w) PF. Furthermore, the inclusion of 5% (w/w) menthol in the composite led to fungistatic activity against Botrytis cinerea, also resulting in homogeneous sheets (tensile strength 24.137 ± 1.439 MPa) and trays (compressive strength 0.113 ± 0.010 MPa). These findings can be applied to the packaging and preservation of perishable produce. Full article

Ni thick films have a wide range of applications in mechanical areas for anti-corrosion, anti-friction and protection purposes, and are also extensively employed in the chip packaging field. Yet, the deposition of Ni thick films is still faced with many problems in deposition efficiency, dense structure and adhesion to the substrate. RF magnetron sputtering was employed to deposit on polished Ti substrate up to 10.8 µm thick Ni films at a high deposition rate (45 nm/min) in Ar atmosphere plus a small amount of H₂. Vacuum annealing was performed at 400 °C for 5 h. To characterize the adhesion via friction and scratch test, different loads were applied on both surfaces of as-sputtered and post-annealed Ni thick films, and results were comparatively analyzed. The films have high purity, compact structure, smooth surface and strong adhesion strength. Post-annealed samples showed better and stable adhesion of Ni thick films to the substrate surface. Full article

The study aimed to assess the influence of two packaging methods (under vacuum, VP vs. air, AP) on the quality of fish balls from carp (Cyprinus carpio) stored at +4 °C up to 14 days after preparation. The air-packed and vacuum-packed fish balls were analyzed for physicochemical parameters, microbiological status, and sensory characteristics. The packaging method and storage time interaction significantly (p < 0.05) affected the acid value (AV) and peroxide value (PV), as well as the thiobarbituric acid reactive substance index (TBARS), with lower values of these parameters observed in vacuum-packed samples at 7 d (AV, PV, TBARS), 9 d (TBARS), 12 d (PV) and 14 d (TBARS) of storage. Moreover, vacuum packaging helped maintain a beneficial oil absorption and pH, and partially slowed down the occurrence of undesirable changes in color, i.e., the decrease in redness of semi-raw fish balls or increase in yellowness of deep-fried products. Based on the overall quality values, the air-packed fish balls were sensory acceptable for up to 9 days, while the vacuum-packed fish balls were acceptable up to 12 d. The bacterial counts (total viable counts—TVC, psychrotrophic bacterial counts—PBC, total staphylococcal counts—TSC, sulfite-producing bacteria counts—SPBC, and lactic acid bacteria counts—LABC) increased during storage. Although the rate and pattern of growth varied depending on the packaging, fish balls maintained the recommended microbiological quality throughout the entire storage period. The VP method inhibited the growth of TVC, PBC, TSC, and SPBC relative to the AP method, while the VP method showed a higher increase in LABC. The results indicated that vacuum packaging appears to be an effective approach to prolong the shelf life of fish balls made from carp. Additionally, developing this convenient food product could be a valuable strategy to enhance consumer acceptance and promote the use of widely farmed carp species. Full article

This study aimed to elucidate the dynamic changes in meat quality attributes and metabolomic profiles of Dezhou donkey longissimus lumborum (LL) during extended chilled storage. Donkey longissimus lumborum (LL) muscles (n = 4) were vacuum-packaged 24 h post mortem and stored at 0–4 °C for 0, 7, 14, or 21 days, followed by a 5-day aerobic display. Meat quality parameters and microstructural characteristics were evaluated, and untargeted metabolomics was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Extended storage significantly improved tenderness (shear force decreased from 76.40 to 27.84 N; p < 0.05), concurrent with progressive muscle fiber degradation. However, color stability deteriorated markedly, with accelerated declines in redness observed beyond 14 days. Metabolomics analysis demonstrated that storage resulted in a substantial accumulation of lysophospholipids, free amino acids, and nucleotide degradation products, indicative of membrane deterioration, proteolysis, and ATP catabolism. Notably, acetyl-L-carnitine, cysteinylglycine (Cys-Gly), and nicotinamide exhibited progressive depletion, correlating with diminished antioxidant capacity and color deterioration. KEGG pathway enrichment revealed significant alterations in glycerophospholipid, amino acid, and glutathione metabolism. This study provides the first comprehensive metabolomic characterization of donkey meat during chilled storage, identifying potential biomarkers for freshness assessment and offering a scientific foundation for developing targeted preservation interventions. Full article

Low-processed ready-to-eat (RTE) meat products are highly vulnerable to microbial contamination, yet data on in-process dynamics remain limited. This study investigated microbial dynamics and environmental hygiene during the production of vacuum-packed RTE pork bars containing dried plasma, with a focus on identifying process-inherent contamination risks. Samples were collected at successive processing stages and from food-contact and non-food-contact surfaces. Process hygiene was assessed using indicator organisms (Aerobic Plate Count, Enterobacteriaceae, lactic acid bacteria, yeast and mold, E. coli, S. aureus counts), while food safety relevance was addressed by monitoring Listeria monocytogenes and Salmonella spp. Microbial counts increased by approximately 1.5–2.3 log CFU/g between early processing steps, indicating that these operations are critical contamination-prone steps. Environmental monitoring revealed contamination hotspots on frequently handled surfaces, highlighting the vulnerability of pre- and post-lethality stages. Despite the baking achieving a mean microbial reduction of ~3 log CFU/g, consistent with effective thermal processing, low-level microbial reappearance during packaging and maturation indicated the potential for post-process contamination. The results demonstrate that production-inherent factors largely drive microbial contamination patterns and may persist even in facilities operating under implemented GHP, GMP, and HACCP-based procedures, highlighting step-specific limitations rather than system failure. By providing empirical data on in-process microbial dynamics, this study supports both scientifically based and risk-based approaches within Food Safety Management Systems, offering transferable insights applicable to similar RTE meat production environments. The findings may assist food business operators in optimising targeted control measures and strengthening risk-based decision-making in low-processed RTE meat production. Full article

To improve the low deposition rate of atomic layer deposition (ALD), we introduced filtered cathodic vacuum arc (FCVA) technology for the high-rate deposition of Al₂O₃ films. The FCVA-Al₂O₃ process achieved a deposition rate of 15 nm/min, which is approximately an order of magnitude higher than that of conventional ALD. This process does not involve hydrogen, preventing hydrogen ion penetration and thereby ensuring the high stability of the oxide TFT backplane. FCVA-Al₂O₃ films were integrated with inkjet-printed (IJP) organic layers to form a hybrid thin-film encapsulation (TFE) structure for OLEDs. The resulting laminated encapsulation exhibited excellent water vapor barrier properties (WVTR, Water Vapor Transmission Rate of 1.2 × 10⁻⁴ g/m²/day), demonstrating the great potential of FCVA for packaging high-throughput and high-performance flexible electronics. In addition to evaluating barrier properties (surface roughness, residual stress, and WVTR) to assess the suitability of TFE, the impact of FCVA technology was assessed via oxide thin-film transistor (TFT) electrical performance and OLED device reliability tests. The electrical properties of oxide TFTs show no significant degradation post-encapsulation, while OLED performance, despite a slight increase in current efficiency, remains effectively unchanged. Additionally, the lifetime of OLED devices reached 300 h under accelerated aging conditions (85 °C, 85% relative humidity), which is nearly twice that of devices without FCVA-Al₂O₃ encapsulation. Full article

Half-smooth tongue sole has high nutritional value due to its delicious meat and high protein content. However, its high protein content makes it highly susceptible to spoilage caused by microbial action. This study utilized plasma-activated water to pretreat half-smooth tongue sole, which was then subjected to various packaging methods: CK (air packaging), VP (vacuum packaging), MAP1 (75% CO₂/5% O₂/20% N₂), MAP2 (20% CO₂/5% O₂/75% N₂), and MAP3 (75% CO₂/10% O₂/15% N₂). The packaged samples were stored at −1 °C. Preservation efficacy was assessed by monitoring changes in microbial counts and physicochemical quality indicators throughout storage. The findings revealed a progressive increase in microbial counts, a deterioration in fish quality, and a darkening of color over extended storage periods. During superchilling storage, the increase in total volatile basic nitrogen (TVB-N) and K value was markedly reduced in the MAP1 group. Regarding protein stability, the MAP1 group exhibited a slower rise in carbonyl content as well as a slower reduction in total sulfhydryl content, further confirming its superior preservation effect. Moreover, this group demonstrated excellence in maintaining the secondary and tertiary structures of myofibrillar proteins, thereby minimizing the structural damage of fish during superchilling storage. In summary, based on observed microbial and protein changes, MAP1 (75% CO₂/5% O₂/20% N₂) was the most effective in preserving quality and extending shelf life. Full article

Protective cultures are an increasingly industrially relevant biopreservation tool for meat and meat products, responding to simultaneous demands for microbiological safety, extended shelf life, and reduced reliance on synthetic preservatives within clean-label frameworks. This review summarizes current advances in protective cultures applied to meat systems, with emphasis on technological functions, efficacy boundaries, and safety-related due diligence. We discuss the dominant inhibitory mechanisms of lactic acid bacteria and related protective taxa—acidification, competitive exclusion, and antimicrobial metabolites (including bacteriocins)—and highlight why performance is strongly strain- and matrix-dependent under realistic storage conditions. Practical applications are reviewed across raw meats (spoilage delay under refrigeration and vacuum/MAP) and processed or ready-to-eat products, where post-processing surface application emerges as a critical control point for limiting Listeria monocytogenes outgrowth during chilled storage. Key implementation constraints include technological compatibility and sensory neutrality, which are influenced by product buffering capacity, salt content, available fermentable substrates, packaging atmosphere, and temperature. From a safety perspective, we synthesize evidence on antimicrobial resistance in food-associated cultures and outline contemporary qualification strategies combining phenotypic susceptibility testing with genome-based screening to exclude acquired and potentially transferable resistance determinants. Overall, protective cultures should be viewed as a targeted hurdle integrated into holistic preservation systems rather than a standalone substitute for hygiene and process control. Full article

The red prickly pear (Opuntia streptacantha) is a fruit that is distinguished by its sensory properties and high content of bioactive compounds. Its rapid spoilage rate significantly impacts its commercialization, underscoring the urgent need for effective preservation methods. This study investigated the effectiveness of various juice preservation techniques—refrigeration, freezing, pasteurization, and vacuum packaging —in maintaining the microbiological quality, physicochemical properties, and antioxidant capacity of red prickly pear juice during storage. The most effective preservation method was found to be freezing the vacuum-packaged and pasteurized juice, referred to as J4. This method adequately maintained key nutritional and physicochemical qualities after 12 months, which was evidenced by a reduction in the microbial growth and the preservation of pH (4.64), acidity (0.74 g citric acid L⁻¹), antioxidant activity (2.6–2.9 mmol TE L⁻¹), as well as the content of phenols (506 mg GAE L⁻¹), betalains (141.2 mg L⁻¹), and total sugars (125 g L⁻¹). Furthermore, sensory analysis comparing J4-treated juice to control juice revealed no significant differences, confirming that J4 is an effective method for preserving the nutritional, functional, and sensory qualities of red prickly pear juice. Full article

To address the low-value recycling dilemma of waste polyvinyl butyral (PVB) and cater to the demand for sustainable multifunctional active food packaging, this study developed a facile and cost-effective solution blow spinning approach. Continuous, smooth, and bead-free nanofiber membranes were prepared by optimizing the solution blow spinning process parameters. Zinc oxide nanoparticles (ZnO NPs) were incorporated into the PVB nanofiber membrane with vacuum impregnation. The results demonstrated that ZnO NPs significantly enhanced the tensile strength, thermal stability, and the UV absorption of PVB fiber membranes. ZnO/PVB fiber membranes exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Practical preservation tests showed that ZnO/PVB fiber membranes effectively inhibited cherry tomatoes’ microbial spoilage and water loss, extending the shelf life of tomatoes to 13 days. These findings validate the potential of ZnO/PVB composite nanofiber membranes as active food packaging and provide a feasible technical pathway for the low-cost, efficient utilization of recycled PVB. Full article

Modern gastronomy strives to combine high-quality food with the preservation of nutritional value, microbiological safety, and the sustainable use of raw materials. With the development of culinary technologies, precise heat treatment methods are gaining increasing importance, enabling better process control and more consistent quality results. This analysis aims to present the effects of the sous-vide (SV) method on the quality of vegetables in comparison with conventional heat treatment methods, such as boiling in water, steaming, cooking under increased pressure, cooking in a microwave oven, baking, grilling, and the cook-vide method. Analysis of the scientific literature has shown that the sous-vide method usually allows for the retention of greater amounts of vitamins (especially vitamin C), phenolic compounds and minerals, resulting in products with higher nutritional value and bioavailability of bioactive ingredients. Maintaining a controlled, low temperature in a vacuum environment reduces the loss of water and volatile components, which has a positive impact on the process yield as well as the color, texture, and aroma of vegetables. SV processing enhances product digestibility, preserves natural appearance, and improves food safety. Due to its hermetic packaging and limited oxygen access, this method ensures good microbiological quality and extends product shelf life. In the food service industry, SV allows for repeatable results, high sensory and technological quality, and reduced food waste. In the context of contemporary nutritional challenges and the experiences of the COVID-19 pandemic, sous-vide technology is gaining importance as a method supporting food safety, sustainability, and efficient resource management in the food service industry. Full article

The cleanliness and functionalization of metal surfaces are critical factors to determining their performance in high-performance microelectronic packaging, reliable biomedical implants, advanced composite bonding, and other fields. Compared to traditional wet cleaning methods, plasma cleaning technology has emerged as a research hotspot in surface engineering due to its unique advantages, such as high efficiency and environmental friendliness. It operates under versatile conditions (e.g., power: tens of watts to several kilowatts; pressure: atmospheric to low vacuum; treatment time: seconds to minutes), enabling not only efficient contaminant removal but also targeted surface functionalization, including dramatically enhanced hydrophilicity (e.g., contact angles from >80° to <10°), significantly improved adhesion (e.g., up to 40% increase in bond strength), and modifications in surface roughness, corrosion resistance, and biocompatibility. This review systematically elaborates on the physical, chemical, and synergistic mechanisms of plasma cleaning technology as it acts on metal surfaces. It focuses on plasma cleaning applied to copper, aluminum, titanium and their respective alloys, as well as alloy steels, providing a detailed analysis of contaminant types, plasma cleaning methodologies, common challenges, surface functionalization responses, and subsequent functional applications. Furthermore, this review discusses the current challenges faced by plasma cleaning technology and offers perspectives on its future development directions. It aims to systematize the research progress in plasma cleaning of metal surfaces, thereby facilitating the transition of this technology towards large-scale industrial applications for metal surface functionalization. Full article