Search Results (132)

Thermoplastic starch (TPS) can be a sustainable alternative to petrochemical plastics for flexible packaging, especially in rainforests and tropical regions where native starch sources such as cassava are abundant. However, one problem preventing TPS packaging from widespread use is its susceptibility to moisture. This study evaluated TPS formulations based on Amazonian cassava starch reinforced with plantain leaf fibers, beeswax, and low-density polyethylene (LDPE) particles. The plastic compounds were extruded to obtain pellets and then films at 120–130 °C. The resulting films were then cut and heat-sealed to obtain flexible packaging. Different properties of the TPS packages were evaluated, such as mechanical strength, water vapor transmission (WVTR), color, infrared spectrum (FT-IR), and moisture adsorption. The results showed that the formulation with beeswax (2% w/w), plantain leaves powder (1% w/w), and LDPE powder (2% w/w) had a higher tensile strength (5.99 MPa) and moisture barrier (WVTR = 366.6 g m⁻² d⁻¹) compared to the control formulation only with plasticizers (glycerol and water) but without reinforcements (0.48 MPa and 1486.6 g m⁻² d⁻¹, respectively). Films with only beeswax (4% w/w) and plantain leaves powder (2.5% w/w) had tensile strength = 5.53 MPa and WVTR = 716.8 g m⁻² d⁻¹, with higher moisture adsorption compared to the samples with LDPE. In both cases, homogeneous and heat-sealable bags were obtained. The reinforced TPS films can be used to reduce the environmental impact generated by single-use packaging applications such as food commercialization. Full article

This research compared grain sorghum with wheat as an ingredient in extruded, floating tilapia feed, and also studied the impact of pre-extrusion grinding intensity or hammer mill sieve size on extrusion parameters, final product quality and animal performance. With an increase in grind size of the diets from 0.61 to 1.27 mm, higher specific thermal energy was observed; however, specific mechanical energy decreased, leading to lower expansion (pooled bulk density of 405.6 g/L versus 441.5 g/L). Grain source also impacted pellet expansion and quality, with sorghum-based aquatic feed pellets having higher piece density than wheat-based pellets (pooled average of 0.52 g/cm³ versus 0.48 g/cm³) and lower water absorption (pooled average of 255.7% versus 334.4%). Digestibility trends with respect to grain and grind size were not consistent for Nile tilapia fed different extruded diets, but results from a 12-week growth trial showed that tilapia fed the sorghum-based diet had a higher weight gain as compared to wheat-based diets (86.0% versus 81.8%). Grind size or grain did not have a statistically significant impact on feed conversion ratio (FCR), but the sorghum-based feed from medium grind had the lowest FCR of 1.03, while the FCR of other treatments ranged from 1.09 to 1.13. These results indicate that grain sorghum can successfully be incorporated into Nile tilapia diets with positive effects on both physical feed quality as well as the growth of the fish. 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

Utilizing forestry and agricultural byproducts like wood and hemp residues advance sustainable additive manufacturing (AM), while reducing material costs. This study investigated the development and characterization of wood–sodium silicate composites incorporating hemp hurd and hemp fibers for AM applications. Formulations varied by wood fiber type (unsifted, 40 mesh, and pellet), sodium silicate concentration (50–60 wt%), and hemp hurd content (0–15 wt%). Properties evaluated include particle size and bulk density of the constituent materials, rheological behavior, extrusion performance, composite bulk density, and flexural and compressive strengths. Rheology and extrusion were largely influenced by the liquid content. Mixtures with low liquid content (50 wt% sodium silicate) had high motor power and low viscosity. As liquid content increased, motor power decreased, while viscosity increased up to 55 wt% and then decreased at 60 wt%. Mechanical properties correlated with particle size, where finer particles enhanced strength. A cost analysis was conducted using raw material prices to determine the economic feasibility of each formulation. Finally, the formulations were evaluated based on strength-to-cost ratios, extrudability and processability. The formulation with pellet wood fibers, 55 wt% sodium silicate, and 10 wt% hemp hurd achieved a high ratio of 73.0 MPa/$ while maintaining low motor power. This formulation offered additional benefits which are discussed qualitatively. Full article

Large-Format Additive Manufacturing (LFAM) offers the ability to 3D print composites at multi-meter scale and high throughput by utilizing a screw-based extrusion system that is compatible with pelletized feedstock. As such, LFAM systems like the Big Area Additive Manufacturing (BAAM) system provide a pathway for incorporating AM techniques into industry-scale production. Despite significant growth in LFAM techniques and usage in recent years, typical Multi-Material (MM) techniques induce weak points at discrete material boundaries and encounter a higher frequency of delamination failures. A novel dual-hopper configuration was developed for the BAAM platform to enable in situ switching between material feedstocks that creates a graded transition region in the printed part. This research studied the influence of extrusion screw speed, component design, transition direction, and material viscosity on the transition behavior. Material transitions were monitored using compositional analysis as a function of extruded volume and modeled using a standard Weibull cumulative distribution function (CDF). Screw speed had a negligible influence on transition behavior, but averaging the Weibull CDF parameters of transitions printed using the same configurations demonstrated that designs intended to improve mixing increased the size of the blended material region. Further investigation showed that the relative difference and change in complex viscosity influenced the size of the blended region. These results indicate that tunable properties and material transitions can be achieved through selection and modification of composite feedstocks and their complex viscosities. Full article

Functional foods represent a new and thriving area of research. A significant direction of these studies is based on new products containing edible house cricket-derived additives. The aim of the presented studies was to determine the effect of using cricket powder (at 10% and 30% content) on the extrusion cooking parameters and the nutritional value, antioxidant activity, and selected physical properties of extruded potato-based snack pellets. The results suggest that house cricket powder is a promising functional ingredient. The processing efficiency and the physical and functional properties of the extrudates, including SME, WAI, WSI, bulk density, and mechanical durability, were affected by the addition of cricket powder, screw speed, and moisture content. Generally, higher levels of cricket powder reduced processing efficiency and altered structural properties due to changes in composition, particularly the balance between protein, fiber, and starch. The addition of cricket powder significantly improved antioxidant activity (>94% of DPPH scavenging for 30% content of additive) and increased the total polyphenol content in the assessed samples in comparison to potato bases (212.3 and 21.7 μg GAE/g dry weight, respectively). These innovative snack pellets containing cricket powder could be an appealing option due to their potential health benefits. Full article

The study aimed to develop extruded snack pellets enriched with fresh lucerne sprouts and to evaluate the effects of this type of additive and processing parameters on extrusion-cooking efficiency, specific energy consumption, and selected physical and antioxidant properties. The results showed that screw speed, feed moisture, and lucerne content were the main factors influencing process efficiency and product quality. Higher lucerne content and feed moisture reduced extrusion-cooking efficiency and increased energy consumption, while a moderate addition (10%) ensured positive physical characteristics and stable processing conditions. Enriching the extrudates with lucerne sprouts significantly increased total phenolic content and antioxidant activity, confirming functional potential. The incorporation of up to 30% fresh lucerne sprouts offers a promising approach to producing functional extruded snacks with improved nutritional value and more sustainable processing. Full article

This study aims to examine the factors influencing the acceptance of extruded pellet (EP) usage among Korea’s olive flounder farming households by analyzing their acceptance factors to provide recommendations for its wider adoption. A survey was conducted among olive flounder farming households, and 188 valid questionnaires were collected. To examine the factors influencing EP acceptance intention, the UTAUT2 (extended unified theory of acceptance and use of technology) model was used. The independent variables were categorized into performance expectancy, effort expectancy, facilitating conditions, social influence, price value, and reliability as independent variables, while acceptance intention was considered as the dependent variable, to derive measurement items. In addition, the differences between the two groups were analyzed by using the aquaculture region and the manager’s experience as moderating variables. The hypothesis testing showed that performance expectancy, effort expectancy, social influence, price value, and reliability factors had a positive effect on acceptance intention, while facilitating conditions did not show a significant effect. The analysis of the moderating effect of the aquaculture region indicated a significant difference between the Jeju-do and Jeollanam-do groups. Conversely, the moderating effect of experience showed no significant difference between those with more experience (≥10 years) and those with less (<10 years). Full article

The increasing demand for safe and durable feed materials highlights the need for processing methods that simultaneously enhance physical quality and reduce microbiological contamination. Extrusion technology offers a promising solution by combining thermal and mechanical effects that improve binding performance while inactivating fungal spores present in cereal grains. In this study, maize, barley, sorghum, soybean, and wheat grains naturally contaminated with fungal spores were subjected to extrusion prior to pelleting. The physical properties of the resulting pellets, including bulk density, physical density, and kinetic durability, were evaluated and compared with those obtained from ground (non-extruded) grains. Pellets containing extruded grains generally exhibited higher physical density, with the highest value recorded for pellets containing extruded mould-infected sorghum grain (1179.82 kg·m⁻³) and the lowest for pellets containing healthy soybeans (1063.63 kg·m⁻³). The kinetic durability of extruded cereal pellets increased on average by 4.02%, enhancing their resistance to mechanical stress during transport and storage. Microbiological analyses confirmed a significant reduction in fungal colony-forming units (CFUs) after extrusion and pelleting, ranging from 27% to 65%, depending on the cereal type. The most pronounced reduction was observed in maize-based pellets contaminated with mould spores, decreasing from 1.70 × 10⁵ to 6.03 × 10⁴ CFU·g⁻¹. These results demonstrate that extrusion is an effective method for producing cereal-based feed materials with improved physical quality and enhanced microbiological safety, contributing to more sustainable feed production. Full article

Atherosclerosis is highly prevalent among captive psittacine populations and is a frequent cause of veterinary consultations. Ante-mortem diagnosis remains challenging, but the serum lipoprotein analysis has been suggested as a useful tool for identifying associated risk factors and improving understanding of its pathogenesis. Unlike in humans, the relationship between lipoproteins and atherosclerosis in parrots has not been clearly established. This retrospective cohort study analyzed n = 1199 blood samples from 692 parrots across 14 genera to establish reference intervals for high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) following ASVCP guidelines. Lipoprotein levels were evaluated in relation to factors such as genus, age, sex, diet, reproductive status, body condition score, and atherosclerosis prevalence (diagnosed by endoscopy and/or necropsy). The results demonstrated genus-specific differences and significant associations between LDL-C and atherosclerosis, with non-HDL-C showing a similar, less pronounced, trend. Higher LDL-C values were measured in the presence of moderate-severe atherosclerosis. Birds on seed diets had higher lipoprotein levels and were more likely to be diagnosed with atherosclerosis in comparison to birds fed a pelleted or extruded diet. The role of HDL-C remained less conclusively defined. The results of this study provide a foundational framework for the future use of lipoprotein analysis in parrot medicine, offering novel insights into the management of cardiovascular health in pet parrots. Full article

Utilizing paste feed within a recirculating aquaculture system for eel cultivation may lead to various challenges, such as water quality degradation and, hence, transitioning to floating pellet type feed becomes essential. In this study, we aimed to investigate the impact of different feed types (paste and floating extruded pellet) and rearing systems (recirculating aquaculture and flow through system) on water quality, growth, blood chemistry, body composition, and expression levels of digestive enzymes in Japanese eels (Anguilla japonica). Throughout the experiment, notable variations were observed in total ammonia nitrogen and nitrite nitrogen levels, with higher concentrations in the recirculating aquaculture system (1.00 ± 0.64 and 0.757 ± 0.464 mg/L, respectively) than paste groups (0.859 ± 0.651 and 0.485 ± 0.502 mg/L, respectively). Significant differences were observed in weight gain and specific growth rates, with the pellet group (154 ± 10% and 1.50 ± 0.06%/day, respectively) exhibiting higher values than the paste group (135 ± 13% and 1.37 ± 0.09%/day, respectively). Blood parameters showed significant differences depending on the culture system, with generally higher values observed in the flow-through system, while no significant differences were observed between feed types. Whole-body composition exhibited variations attributed to feed intake, with notable differences in crude protein and crude fat content among the experimental groups. The expression levels of digestive enzymes and nutrient transporters were higher when the eels were fed pellet-type feed and reared in recirculating aquaculture system. The study findings indicate that pellet feed enhances water quality management in RAS, leading to improved eel growth. Given its lower environmental stress, pellet feed is preferable to paste feed for optimizing eel production in RAS. Full article

The increasing accumulation of plastic waste—especially from packaging and post-consumer sources—calls for the development of sustainable recycling strategies. Due to the challenges associated with sorting mixed waste, directly processing waste streams offers a practical approach. Polyethylene terephthalate (PET) and high-density polyethylene (HDPE) are common consumer plastics, but they are difficult to recycle together due to immiscibility and degradation. In mixed waste, recycled HDPE (r-HDPE) often contaminates the recycled PET (r-PET) stream. Additive manufacturing (AM) offers a promising solution to upcycle these mixed polymers into functional products with minimal waste. This study investigates the processing and characterization of r-PET/r-HDPE blends for AM, focusing on the role of compatibilizers in enhancing their properties. Blends were melt-compounded using a twin-screw extruder to improve dispersion, followed by direct pellet-based 3D printing. A compatibilizer (0–7 php) was incorporated to improve miscibility. Rheological testing showed that the 5 php compatibilizer optimized viscosity and elasticity, ensuring smoother extrusion. Thermal analysis revealed a 30 °C increase in crystallization temperature and a shift in decomposition temperature from 370 °C to 400 °C, indicating improved thermal stability. Mechanical testing showed a tensile strength of 35 MPa and 17% elongation at break at optimal loading. Scanning electron microscopy (SEM) confirmed reduced phase separation and improved morphology. This work demonstrates that properly compatibilized r-PET/r-HDPE blends enable sustainable 3D printing without requiring polymer separation. The results highlight a viable path for the conversion of plastic waste into high-value, customizable components, contributing to landfill reduction and advancing circular economy practices in polymer manufacturing. Full article

Polymer 3D printing is popular due to its accessibility and low material waste. While commonly used in prototyping and medical applications, its potential for molds in complex concrete geometries, such as heritage reproductions or artificial reefs, remains underexplored. These applications require resistance to degradation from UV exposure, rain, and highly alkaline concrete (pH~13). This study evaluates the accelerated degradation of 3D-printed PLA specimens. Four PLA types were tested: virgin PLA extruded in the lab, commercial PLA, PLA with 50% metal powder, and PLA with encapsulated metal powder. Rectangular specimens were printed and tested under flexural loads following ISO-167 standards. Initially, their performance was assessed without exposure. Then, half of the specimens underwent UV and rain simulation, while the rest were immersed in an alkaline solution (pH 13, 50 °C). Dimensional changes and flexural strength were measured at five intervals. Exposure to an alkaline medium at 50 °C is more aggressive than UV radiation, limiting the lifespan of PLA formwork. Adding metal powder weakens PLA by 65% after 7 days, making it unsuitable. Printing defects accelerate degradation. Unmodified PLA is the best choice for concrete formwork, with commercial PLA and PLA from pellets showing nearly identical behavior. Full article

By-products generated in the agri-food industry are frequently regarded as waste, despite their significant potential for reutilization as valuable raw materials with both nutritional and functional properties. Nigella and flaxseed pomace, as rich sources of bioactive compounds, have the capacity to enhance the nutritional profile and functional characteristics of extruded products while simultaneously contributing to the reduction in food waste. Uniquely, the present study analyzed the effect of extrusion-cooking process conditions on the efficiency, energy consumption, and selected physical properties of extrudates enriched with nigella and flaxseed pomace. The samples were made using a single-screw extruder-cooker. Two plasticizing (L/D 16 and 20) systems were compared. The highest efficiency, 23.16 kg/h, was reached using 20% nigella pomace with the L/D 16 system. During the whole process, the specific mechanical energy ranged from 0.006 to 0.105 kWh/kg. New information was obtained on the interaction between pomace content and the physical properties of the extrudates. The results showed that the use of 10% nigella pomace maximized the WAI 4.90 and WSI 11.73% for pellets with 30% of nigella seed pomace in the L/D 20 and influenced the change in bulk density, indicating a double innovation: an improvement in extrudate quality and the efficient use of by-products. Full article

The significant waste generated by the fashion industry necessitates sustainable textile recycling strategies. Polyester, made from poly(ethylene terephthalate) (PET), is abundant in post-consumer textiles. Technologies have been developed to convert low-density garment waste into flakes, but the role of color sorting in achieving uniform aesthetics in injection-moldable plastics remains underexplored. This study compares materials extruded from dark color-sorted polyester garment flakes with those from light-color flakes in terms of processability in extrusion and injection molding. The properties examined include melt fluidity, injection molding shrinkage, and mechanical and thermal properties. Commercial chain extenders with anhydride, oxazoline, or epoxide reactive groups were added during extrusion. Interestingly, only dark-colored extruded pellets showed significant degradation, but all the chain extenders allowed melt fluidity to be controlled during reprocessing. The bisoxazoline-based additive was the most promising, due to the highly improved ductility of the samples, regardless of whether they were dark-colored or light-colored. The results indicate significant potential for the industrial recycling of post-consumer textiles and highlight the industrial feasibility of repurposing post-consumer polyester garments. This approach not only supports initiatives of circular economy but also offers a viable solution for managing textile waste, particularly in the fashion industry. Additionally, the suggested recycling route combats the production of microplastics. Full article