Search Results (116)

(1) Background: This study aimed to investigate the bacterial microbiomes in the ingredients and final PBM products during a storage period of 28 days at 2–4 °C for food safety and quality. (2) Methods: DNA from raw ingredients (i.e., defatted soy flour, potato starch, wheat gluten, mung bean protein, and duckweed) and three PBM formulations were extracted and sequenced using 16S rRNA gene sequencing. (3) Results: Alpha diversity (Simpson and Shannon) was high in the raw ingredients (p ≤ 0.05). Beta diversity showed dissimilarities between the samples. Firmicutes and Proteobacteria were the core microflora in these ingredients. The heat-stable microbes in PBM (e.g., Nostocaceae in SF and Cyanobacteriale in MB and DW) survived after extrusion. After the ingredients were stored at room temperature, the bacterial communities shifted, with Paucibacter being the majority population in raw ingredients and PBM in the 2nd batch. The predictions of Potential_Pathogens related to the abundance of Aeromonadaceae and Enterobacteriaceae need to be monitored during storage. (4) Conclusions: Our results showed that the bacterial community in PBM containing 30% MB and 3% DW did not drastically change during 28 days of storage at cold temperatures. Uncovering bacterial microbiomes in the ingredients should be emphasized for quality and safety, as ingredients influence the microbiome in the final products. Full article

There is a demand for a 6005A series extrusion alloy with improved strength that maintains good extrudability. Replacing Mn and Cr dispersoid formers with Sc and Zr is expected to increase the room temperature mechanical properties while not affecting extrudability. Al₃X dispersoids with a Sc core surrounded by a Zr shell are stable at higher temperatures and enhance recrystallization resistance and precipitation strengthening. However, there is little information on how the Sc and Zr additions affect the properties of an extrudate as a function of extrusion geometry and ratio. A 6005A series alloy with Cr and Mn additions is compared to an alloy with Sc and Zr additions with rod and flat cross-sections at extrusion ratios of 25 and 92. The results show that Sc and Zr additions increased yield strength and ultimate tensile strength while maintaining ductility compared to Cr and Mn additions. Rod shapes performed significantly better than flat shapes, but there was no significant effect of extrusion ratio. Full article

This study compares the microstructures and mechanical properties of the AlSi10Mg alloy processed by laser powder bed fusion (LPBF) after undergoing different post-processing techniques. These techniques include conventional extrusion at 350 °C (CE-350) and KOBO extrusion at both room temperature (KOBO-RT) and 350 °C (KOBO-350). The extrusion processes, regardless of the method used, effectively densified the alloy, fragmented the primary silicon network, and refined the grain structure. Notably, a microstructure analysis indicated that the CE-350 method produced the finest grains, whereas the KOBO-350 method resulted in the largest grains. From a mechanical perspective, extrusion significantly increased ductility—rising from 2.4% to more than 14% elongation—while decreasing strength compared to the as-built state. Among the extruded samples, CE-350 provided the best balance of strength and ductility, exhibiting a yield strength of 186 MPa and a ductility of 18.1% elongation. Overall, the results demonstrate that while extrusion enhances ductility, it does so at the expense of strength, with conventional extrusion yielding a more favorable property balance for this alloy under the tested conditions. Full article

The existing Al-Ce heat-resistant alloys are not extensively utilized in high-temperature applications due to their poor room-temperature mechanical properties. In this study, the Al-10Ce-3Mg-5Zn alloy was enhanced using hot extrusion and heat treatment. The as-extruded alloy exhibited bimodal intermetallic compounds and grain structures. Additionally, high-density microcracks and twins were observed in the micron-sized intermetallic compounds. Compared with the as-cast state, the as-extruded alloy demonstrated a higher ultimate tensile strength (UTS) of 317 MPa and better elongation of 11.0%. Numerous nano-sized T phases precipitated in the α-Al matrix after the heat treatment, contributing to a further rise in UTS (365 MPa). The high strength of the alloy is primarily due to its strong strain hardening capacity, fine grain strengthening, and precipitation strengthening effect. The change in elongation mainly results from the expansion of pre-existing microcracks, twin deformation, and microstructural refinement. The heat-treated alloys exhibited superior strength retention ratios at elevated temperatures (64% at 200 °C) compared to conventional heat-resistant aluminum alloys. The results of this paper indicate that hot extrusion and heat treatment are effective for developing heat-resistant Al-Ce alloys with high room-temperature strength, offering a simple process suitable for industrial production. Full article

This study investigates the phytochemical profile, antioxidant and anti-inflammatory properties, and 3D-printing application of Origanum vulgare L. ssp. hirtum extract. The extract revealed a diverse range of phenolic compounds, with rosmarinic acid as the predominant compound (47.76%). The extract showed moderate to high lipoxygenase inhibition (IC₅₀ = 32.0 µg/mL), suggesting its potential as an anti-inflammatory agent. It also exhibited strong antioxidant activity, with hydrogen peroxide scavenging (SC₅₀ = 99.2 µg/mL) and hydroxyl radical scavenging (IC₅₀ = 64.12 µg/mL) capabilities. In cellular studies, high concentrations (50 µg/mL and 100 µg/mL) significantly decreased intracellular ROS production in Caco-2 cells (reductions exceeding 53% and 64%, respectively). Moreover, the extract suppressed NO production in LPS-stimulated J774A.1 macrophages in a concentration-dependent manner. The study also explores the incorporation of the extract into 3D-printed gummies. The gels exhibited a shear-thinning behavior, which was essential for successful extrusion-based 3D printing. The incorporation of Origanum extract significantly influenced the mechanical strength and compaction properties of the 3D-printed gummies before breaking (1.6-fold increase) allowing for a better mouth feeling. PXRD and FTIR analyses confirmed the amorphous nature of the 3D-printed gummies and the interaction between active ingredients and excipients utilized for printing. These findings demonstrated the potential for semisolid extrusion 3D printing at room temperature to transform a culinary herb (Origanum vulgare spp. hirtum) into a healthcare product with antioxidant and anti-inflammatory properties. Full article

Magnesium and its rare-earth alloys are extensively studied for their lightweight properties and high specific strength, making them attractive for aerospace, automotive, and biomedical applications. However, their hexagonal close-packed structure leads to a strong basal texture, limiting plasticity and formability at room temperature. Considerable research has been devoted to texture control strategies, including alloying, thermomechanical processing, and recrystallization mechanisms, yet a comprehensive understanding of their effects remains an ongoing research focus. This review summarizes recent advances in texture regulation of rare-earth magnesium alloys, focusing on the role of RE elements (Gd, Y, Nd, Ce) and non-RE elements (Zn, Ca) in modifying basal texture and enhancing mechanical properties. The influence of key processing techniques, such as extrusion, rolling, equal channel angular pressing, and rotary shear extrusion, is discussed in relation to their effects on recrystallization behavior. Additionally, the mechanisms governing texture evolution, including continuous dynamic recrystallization, discontinuous dynamic recrystallization (DDRX), and particle-stimulated nucleation, are critically examined. By integrating recent findings, this review provides a systematic perspective on alloying strategies, processing conditions, and recrystallization pathways, offering valuable insights for the development of high-performance magnesium alloys with improved formability and mechanical properties. Full article

To address unpredictable flavor changes in postharvest peaches during storage, this study investigated the use of bioactive packaging with melatonin-infused P34HB films. Films with melatonin concentrations of 0%, 1%, 3%, and 5% were prepared using the extrusion casting method and applied to peach storage at room temperature. Comprehensive film properties were characterized, showing that melatonin minimally impacted the films’ mechanical properties, including gas and water vapor permeability, but significantly increased film haze. Using GC-IMS, 30 organic compounds affecting peach flavor were effectively identified, including 8 aldehydes, 5 alcohols, 4 ketones, 12 esters, 1 pyrazine, 1 olefin, and 1 furan. Unpackaged, naturally ripening peaches served as a reference for assessing flavor and quality changes across various packaging groups during storage. The results indicated that the appearance of off-flavor organic compounds, such as ethanol produced by peach anaerobic respiration and complex esters, was the primary cause of flavor deterioration. The P34HB film with 1% melatonin most effectively preserved the original flavor and juiciness of peaches, highlighting its potential as an active packaging solution for fruit. Full article

Three-dimensional (3D) printing attracts significant interest in the food industry for its ability to create complex structures and customize nutritional content. Printing materials, or inks, are specially formulated for food or nutraceuticals. These inks must exhibit proper rheological properties to flow smoothly during printing and form stable final structures. This study evaluates the relationship between rheological properties and printability in phytosterol-enriched monoglyceride (MG) oleogel-based inks, intended for nutraceutical applications. Key rheological factors, including gelation temperature (Tg), elastic (G′) and viscous (G″) modulus, and viscosity (µ) behavior with shear rate ($\dot{\gamma }$), were analyzed for their impact on flow behavior and post-extrusion stability. Furthermore, this study allowed the development of an operation map to predict successful printing based on material µ and Tg. Oleogels (OGs) were prepared with high-oleic sunflower oil (HOSO) and 10 wt% MG, enriched with phytosterols (PSs) at concentrations between 0 and 40 wt%. While higher PS content generally led to an increase in both Tg and µ, the 10 wt% PS mixture exhibited a different behavior, showing lower Tg and µ compared to the 0 wt% and 5 wt% PS mixtures. The optimal PS concentration was identified as 20 wt%, which exhibited optimal properties for 3D printing, with a Tg of 78.37 °C and µ values ranging from 0.013 to 0.032 Pa.s that yielded excellent flowability and adequate G′ (3.07 × 10⁶ Pa) at room temperature for self-supporting capability. These characteristics, visualized on the operational map, suggest that 20% PS OGs meet ideal criteria for successful extrusion and layered deposition in 3D printing. Full article

Due to limited slip systems activated at room temperature, the plastic deformation of Mg and its alloys without any preheating of initial billets is significantly limited. To overcome those issues, new methods of severe plastic deformation are discovered and developed. One such example is extrusion with an oscillating die, called KoBo. This method, due to the oscillations of reversible die located at the end of extruded, introduces material into the plastic flow, and thus, enables deformation without preheating of the initial billets of metals that are hard to deform. Such solution is important from an industrial point of view and may lead to serious savings and reduction in carbon dioxide emission to the atmosphere. Therefore, this paper focuses on the possibility of KoBo extrusion of hcp-structured Mg alloys with different chemical compositions and includes comparison of their corrosion resistance using short-term electrochemical tests. In order to have a broad view of the problem presented, we compared the electrochemical behavior of the following groups of Mg materials: pure Mg, Mg-Al-Zn, Mg-Li, and Mg-Y-RE. It was stated that the KoBo method performed at room temperature improves the corrosion resistance of pure Mg when compared to the initial billet and the alloys which belong to the Mg-Al-Zn, Mg-Li, and Mg-Y-RE series. The presented study shows that different corrosion trends are observed for traditionally deformed alloys, and they significantly vary from nascent developments, such as KoBo extrusion. Therefore, it is crucial to widely study those methods because it may be a path leading to long-lasting solution to the formability limitations of Mg-based metallic systems. Full article

Understanding the performance of polymer dielectrics at different temperatures is becoming increasingly important due to the rapid development of electric cars, electromagnetic devices, and new energy production solutions. Cyclic olefin copolymers (COCs) are an attractive material due to their low water absorption, good electrical insulation, long-term stability of surface treatments, and resistance to a wide range of acids and solvents. This work focused on the dielectric and electrical properties of cyclic olefin copolymer (COC)/Al₂O₃ composites over a wide range of temperature and frequency domains, from room temperature to cryogenic temperatures (around 125 K). Permittivity, electrical conductivity, and electrical modulus are given consideration. A composite of up to 50% Al₂O₃ mixed with COC was prepared via a conventional melt-blending method. The final samples were formed in sheets and processed using injection and extrusion moldings. It was found that formulations with Al₂O₃ concentrations ranging from 10 to 50% resulted in higher electrical conductivity while maintaining the viscosity of the composite at a level acceptable for polymer-processing machinery. Our data show that COC/alumina composites present substantial potential as materials for high-frequency applications, even at the regime of cryogenic temperatures. Full article

In today’s pharmaceutical landscape, there’s an urgent need to develop new drug delivery systems that are appealing and effective in ensuring therapeutic adherence, particularly among paediatric patients. The advent of 3D printing in medicine is revolutionizing this space by enabling the creation of precise, customizable, and visually appealing dosage forms. In this study, we produced 250 mg metformin paediatric gummies based on the semi-solid extrusion (SSE) 3D printing technique. A pharmaceutical ink containing metformin was successfully formulated with optimal flow properties suitable for room-temperature printing. Using a quality by design approach, 3D printing and casting methodologies were compared. The 3D-printed gummies exhibited better firmness and sustained release at earlier times to avoid metformin release in the oral cavity and ensure palatability. The texture and physical appearance match those of gummies commercially available. In conclusion, SSE allowed for the successful manufacture of 3D-printed sugar-free gummies for the treatment of diabetes mellitus for paediatric patients and is an easily translatable approach to clinical practice. Full article

This study focuses on developing an encapsulated and dehydrated formulation of vegetative actinobacteria cells for an efficient application in sustainable agriculture, both as a fungicidal agent in crop protection and as a growth-stimulating agent in plants. Three strains of actinobacteria were used: one from a collection (Streptomyces sp.) and two natives to agricultural soil, which were identified as S3 and S6. Vegetative cells propagated in a specific liquid medium for mycelium production were encapsulated in various alginate–chitosan composites produced by extrusion. Optimal conditions for cell encapsulation were determined, and cell damage from air-drying at room temperature was evaluated. The fresh and dehydrated composites were characterized by porosity, functional groups, size and shape, and their ability to protect the immobilized vegetative cells’ viability. Actinomycetes were immobilized in capsules of 2.1–2.7 mm diameter with a sphericity index ranging from 0.058 to 0.112. Encapsulation efficiency ranged from 50% to 88%, and cell viability after drying varied between 44% and 96%, depending on the composite type, strain, and airflow. Among the three immobilized and dried strains, S3 and S6 showed greater resistance to encapsulation and drying with a 4 L·min⁻¹ airflow when immobilized in coated and core-shell composites. Encapsulation in alginate–chitosan matrices effectively protects vegetative actinobacteria cells during dehydration, maintaining their viability and functionality for agricultural applications. Full article

The microstructure and mechanical properties were investigated for Mg–6Zn–1Y–3.5CeMM (wt.%) alloy processed by extrusion at 400 °C of as-cast ingots (ACE alloy) or cold-compacted atomized powders (PME alloy). The use of fine-grained atomized powders results in a refinement of the microstructure, manifested by a reduced grain size and a smaller particle size with respect to the alloy processed by casting. The second-phase particles are the same for both W-phase (Mg₃Zn₃Y₂) and T-phase (MgZnCeMM compound) particles, regardless of the processing route. The yield stress of the PME alloy at room temperature is not only increased by almost 40% compared with that of the ACE alloy (307 and 224 MPa, respectively), but the elongation to failure also increases to twice as much for the PME alloy. This differing mechanical behavior is related to the smaller grain size and the homogeneous distribution of the second-phase particles in the PME alloy. Up to 200 °C, both alloys maintain high mechanical strength, with UTS values remaining above 120 MPa. At high temperatures and low strain rates, deformation is controlled by grain boundary sliding, improving the ductility at the expense of a significant decrease in the yield strength of the ACE and PME alloys. Full article

In this study, the relationship between the extrusion ratio and the corrosion resistance of pure Mg deformed using extrusion with an oscillating die (KoBo) without preheating of the initial billet was investigated. The materials investigated in this study were extruded at high deformation ratios, R₁ 5:1, R₂ 7:1, and R₃ 10:1, resulting in significant grain refinement from the very coarse grains formed in the initial billet to a few µm in the KoBo-extruded samples at room temperature, which is not typical for hexagonal structures. Our research clearly shows that KoBo extrusion improves the corrosion performance of pure Mg, but there is no straightforward dependence between the extrusion ratios and corrosion resistance improvement. Although it was expected that the smallest grain size should provide the highest corrosion resistance, the dislocation density accumulated in the grain interiors during deformation at the highest extrusion ratio, R₃ 10:1, supports dissolution reactions. This, in turn, provides the answers for the greater grain size observed after deformation at R₂ 7:1, where dynamic recovery prevailed over dynamic recrystallization. This situation led to the annihilation of dislocation, leading to better corrosion resistance of the respective alloy. Therefore, the alloy with the greatest grain size has the best corrosion resistance. Full article

The effect of Al or Cu content on the microstructure and mechanical properties of continuous casting and extrusion Zn alloys has been studied by a room temperature tensile test, X-ray diffraction, and scanning electron microscope. With the increase in Al content, the microstructure of continuous casting and extrusion Zn alloys slightly coarsens, and the lamellar eutectic structure increases. The changes in the above structural factors result in a slight decrease in strength and a significant increase in the elongation of Zn-Al alloys. The strength of Zn alloys increases as the Cu content increases due to the increased content and size of the second phase in the Zn alloys. This means that the mechanical properties of Zn alloys can be adjusted by a continuous casting and extrusion process, and the improvement of equipment capacity can improve the structure and morphology of the alloys. Full article