Search Results (105)

This study aimed to optimize the inoculation dosage and fermentation duration to enhance the protein content and reduce soluble oligosaccharides in soybean meal using Aspergillus oryzae and assessed its performance in dog food extrusion. A 3 × 5 factorial design was used to determine the optimal fermentation conditions. These conditions were applied to ferment soybean meal in bulk for nutritional analysis. Finally, the impact of fermentation on extrusion processing was assessed by formulating and extruding four diets: SBM (30% soybean meal), AMF (30% soybean meal with 1% Amaferm^®—A. oryzae biomass), FSBM (30% fermented soybean meal), and SPI (18% soy protein isolate). Diets were extruded with a single-screw extruder, and physical characteristics of kibbles, particle size distribution, and viscosity of raw mixes were analyzed. The optimal fermentation conditions were 1 × 10⁴ spore/g substrate for 36 h, which increased the crude protein content by 4.63% DM, methionine and cysteine total content by 0.15% DM, and eliminated sucrose, while significantly reducing stachyose, raffinose, and verbascose (95.22, 87.37, and 41.82%, respectively). The extrusion results showed that FSBM had intermediate specific mechanical energy (SME), in-barrel moisture requirements, and sectional expansion index (198.7 kJ/kg, 28.2%, and 1.80, respectively) compared with SBM (83.7 kJ/kg, 34.5%, and 1.30, respectively) and SPI (305.3 kJ/kg, 33.5%, and 2.55, respectively). The FSBM also exhibited intermediate particle size distribution and the least raw mix viscosity. These findings demonstrate that A. oryzae fermentation enhances the nutrient profile of soybean meal while improving extrusion efficiency and kibble quality, supporting its potential use as a sustainable pet food ingredient. Full article

This study investigates the feasibility of self-producing polylactic acid (PLA) filament for use in 3D printing. The filament was fabricated using a desktop single-screw extruder and evaluated against commercially available PLA in terms of mechanical properties and energy consumption. Specimens were printed at two layer heights (0.2 mm and 0.3 mm) and four infill densities (25%, 50%, 75%, and 100%). The self-produced filament exhibited lower diameter precision (1.67 ± 0.21 mm), which resulted in mass variability up to three orders of magnitude higher than that of the commercial filament. Thermal analysis confirmed that the extrusion and printing process did not significantly alter the thermal properties of PLA. Mechanical testing revealed that a layer height 0.3 mm consistently yielded higher stiffness and tensile strength in all samples. When normalized by mass, the specimens printed with commercial filament demonstrated approximately double the ultimate tensile strength compared to those that used self-produced filament. The energy consumption analysis indicated that a 0.3 mm layer height improved printing efficiency, cutting specific energy consumption by approximately 50% and increasing the material deposition rate proportionally. However, the total energy required to print with self-produced filament was nearly three times higher than that for commercial filament, primarily due to material waste that stems from inconsistencies in the diameter of the filament. These findings are significant in evaluating the practicality of self-produced PLA filament, particularly in terms of mechanical performance and energy efficiency. Full article

The inherent brittleness of bio-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) significantly restricts its industrial applications despite its industrial compostability. Blending with elastomeric polymers addresses mechanical limitations; however, interfacial incompatibility compromises miscibility as our previous work established. Herein, we investigate coffee oil epoxide (COE) as a bio-based plasticizer for PHBV/natural rubber (NR) blends in sustainable packaging applications. COE, derived from spent coffee grounds, was incorporated into PHBV/NR/peroxide/coagent composites via twin-screw extrusion. FTIR spectroscopy with chemometric analysis confirmed successful COE incorporation (intensified CH₂ stretching: 2847, 2920 cm⁻¹; reduced crystallinity), with PCA and PLS-DA accounting for 67.9% and 54.4% of spectral variance. COE incorporation improved optical properties (7.73% increased lightness; 21.9% reduced yellowness). Rheological characterization through Cole–Cole and Han plots demonstrated enhanced phase compatibility in the PHBV/NR/COE blends. Mechanical testing showed characteristic reductions in flexural properties: strength decreased by 16.5% and modulus by 36.8%. Dynamic mechanical analysis revealed PHBV/NR/COE blends exhibited a single relaxation transition at 32 °C versus distinct glass transition temperatures in PHBV/NR blends. Tan δ deconvolution confirmed the transformation from bimodal distribution to a single broadened peak, indicating enhanced interfacial interactions and improved miscibility. These findings demonstrated COE’s potential as a sustainable additive for biodegradable PHBV-based packaging while valorizing food waste. 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 effects of cellulase–xylanase synergistic treatment combined with twin-screw extrusion on the physicochemical, functional, and in vitro fermentation characteristics of buckwheat bran dietary fiber (BBDF) were investigated. Compared to single enzymatic hydrolysis, the synergetic modification was more effective in promoting the soluble DF (SDF) ratio (increased from 10.68% to 32.67%), functional properties, and prebiotic activities of BBDF and decreasing the insoluble DF (IDF) content. Under 0.6% (w/w) cellulase and xylanase with mild extrusion conditions (40–80 °C), the modified BBDF exhibited the highest capacities for glucose and cholesterol adsorption. FTIR and XRD experiments indicated that the enzymatic extrusion destroyed the intermolecular interactions of BBDF. Furthermore, enzymatically extruded BBDFs showed 2.2-fold higher short-chain fatty acid (SCFA) yields during in vitro fecal fermentation (total SCFAs: 87.8 mM vs. 40.0 mM in control), with butyrate production reaching 2.5 mM (+76.3%), among which the mildly extruded BBDFs exhibited superior prebiotic effects. Full article

This study evaluated fermented plant protein (FPP) for extrusion performance and its effects on diet utilization in adult cats. Four diets were formulated: a control with 15% soybean meal (SBM) and three diets replacing soybean meal at 5%, 10%, and 15% with FPP (5FPP, 10FPP, and 15FPP). Diets were extruded using a single-screw extruder, with data and samples collected at 15 min intervals. Twelve cats participated in a 4 × 4 Latin square design, with 9 days of diet adaptation followed by 5 days of total fecal collection for nutrient digestibility and colonic fermentation analysis. Processing effects of FPP inclusion were minimal. The kibble sectional expansion index was lowest for SBM (2.50) and highest for 15FPP (2.82; p < 0.05). Fecal moisture increased (p < 0.05) in cats fed 15FPP. The apparent total tract digestibility of protein was greatest (p < 0.05) in cats fed 15FPP. The fecal ammonia concentrations increased linearly (p < 0.05) with FPP, while total fatty acid concentrations were lower (p < 0.05) in cats fed 10FPP compared to SBM. Cats preferred (p < 0.05) 10FPP over SBM as measured by the intake ratio. The FPP inclusion (up to 15%) did not adversely affect processing, stool quality, or nutrient digestibility. Diets with 5–10% FPP tended to reduce hind-gut fermentation. Full article

Extrusion is a key process in the production of ready-to-eat snacks, with a wide processing capacity of non-conventional raw materials such as jackfruit seed flour and nixtamalized corn, which improves the nutritional profile of the snacks. This study aims to optimize the extrusion cooking parameters of extrusion temperature (ET), moisture content (MC), and the ratio of jackfruit seed flour in nixtamalized maize flour (JSF/NMF) to enhance the physicochemical properties of ready-to-eat extruded products. The process parameters and JSF/NMF were optimized using a Box–Behnken design and response surface methodology. JSF/NMF and ET were found to significantly (p < 0.05) affect specific mechanical energy (SME), the expansion index (EI), hardness (H), the water absorption index (WAI), the browning index (BI), and overall acceptance (OA). The optimal conditions were an ET of 145.15 °C, MC of 22 g/100 g, and JSF/NMF of 70 g/100 g, which led to an extrudate with an SME of 273.38 J/g, EI of 1.12, H of 58.75 N, WAI of 6.14 g/g, BI of 61.68, OA of 4.56, protein content of 12.10 g/100 g, and fiber content of 4.86 g/100 g. It was demonstrated that the use of jackfruit seed flour and nixtamalized maize flour as non-conventional flour in the preparation of ready-to-eat snacks through extrusion was feasible in a single-screw extruder, obtaining favorable results in quality parameters that characterize extruded snacks. Full article

In this study, the effect of various parameters of a single screw extruder on the rheology and mechanical properties of a polylactic acid (PLA) filament with a 1.75 mm diameter was investigated. The barrel temperature, nozzle and cooling bath temperature, screw speed, nozzle diameter, water bath length, and distance to the nozzle were the process variables. A Taguchi experimental design was implemented using an L8 orthogonal matrix with seven factors and two levels, and their influence on roundness and diameter were evaluated. Among the various processing parameters, the temperature of the cooling bath affected the roundness the most. The mechanical properties and surface roughness of the PLA filament were examined using a tensile test and nanofocus optical system, respectively. Moreover, to assess the filament’s reliability and investigate its behavior further, the filament was used to print 0° plates, and then dog-bone samples were cut from them to evaluate the mechanical properties of the printed specimens. Finally, the results indicate that improved-roundness filaments of 0.004 mm can lead to enhanced mechanical properties in 3D-printed samples with 3.54 MPa. Full article

The environmental challenges posed by laboratory plastic waste, particularly single-use items, underscore the urgent need for sustainable alternatives. This study investigated the development of reusable and biodegradable labware, addressing both functional and environmental demands. The content of the biodegradable additive in the polypropylene (PP) varied from 1% to 2% by weight via twin-screw extrusion, followed by injection molding to fabricate test specimens. Three different grades of PP were also compared. Optical, mechanical, and thermal properties were systematically assessed before and after repetitive autoclave sterilization for up to 10 cycles (121 °C, 15 min, 0.11 MPa). Additionally, cytotoxicity following electron beam irradiation (E-Beam 25 and 50 kGy) was evaluated in compliance with ISO 10993-5, alongside biodegradability studies conducted under ASTM D5511 conditions. The results demonstrate that the biodegradable additive stabilized the appearance and enhanced the flexural and impact strengths of PP without compromising thermal stability, particularly after five autoclave cycles. Cytotoxicity assays confirmed the biocompatibility of the additive-modified PP, while biodegradability tests indicated moderate degradation, with 12% biodegradation achieved over 6 months compared to negligible degradation in the negative control. These findings highlight the potential of additive-modified PP as a sustainable solution for reusable labware, balancing durability with improved environmental performance and providing a viable step toward more sustainable laboratory practices. Full article

Today’s materials must meet high mechanical requirements while remaining cost-effective in production. This requires a homogeneous temperature and material distribution and splitting, as achieved by mixing elements in single-screw extrusion, which depends on the material properties, the geometry of the mixing elements, and the process conditions. Existing computational fluid dynamics (CFD) methods can help, but often optimize dispersive (split) or distributive (spread) mixing separately and neglect their mutual influence and competition, which prevents a single optimal solution. To address this, this work develops an automated optimization tool using a genetic algorithm for the holistic optimization of both mixing processes, considering pressure drop, temperature gradient, and quantitative metrics for dispersive and distributive mixing. Compromises between geometry and metrics that improve dispersive mixing while maintaining moderate temperature gradients and pressure drops were determined for four different polymers. The results of the dispersive mixing element show dependencies between mixing metrics and geometry. In contrast, the distributive mixing element shows no clear correlations between mixing metrics and geometry. Full article

This study presents the design, modeling, and validation of a mixing screw for energy-efficient single-screw extrusion. The screw features a short length-to-diameter (L/D) ratio of 8:1 and incorporates double flights with variable pitch and counter-rotating mixing slots. These features promote enhanced plastication by breaking up the solid bed and improving thermal homogeneity through backflow mechanisms relieving a 3.75 compression ratio. Non-isothermal, non-Newtonian simulations modeled the thermal and flow behavior for high-impact polystyrene (HIPS) and recycled polypropylene (rPP) under various operating conditions. Experimental validation was conducted using a 20 mm pilot-scale extruder with screw speeds ranging from 10 to 40 RPM and barrel temperatures of 220 °C and 240 °C. Results showed a strong linear dependence of mass output on screw speed, with maximum mass throughputs of 0.58 kg/h for HIPS and 0.74 kg/h for rPP at 40 RPM. Specific energy consumption (SEC) was calculated as 0.264 kWh/kg for HIPS and 0.344 kWh/kg for rPP, corresponding to efficiencies of 31.5% and 56.5% relative to theoretical minimum energy requirements. Compared to traditional general-purpose and barrier screws with L/D ratios of 27:1, the mixing screw demonstrated improved energy efficiency and reduced residence time distributions. These findings suggest the potential of the mixing screw for compact extrusion systems, including 3D printing and other sustainable polymer and bioplastics processing applications. Full article

The aim of this study was to investigate the effects of extrusion processing parameters—moisture content (M = 20 and 24%), feeding rate (FR = 20 and 25 kg/h), and screw speed (SS = 300, 390 and 480 RPM), on the content of deoxynivalenol (DON), 15-Acetyl Deoxynivalenol (15-AcDON), 3-Acetyl Deoxynivalenol (3-AcDON), HT-2 Toxin (HT-2), tentoxin (TEN) and alternariol monomethyl ether (AME), using a pilot single-screw extruder in whole-grain triticale flour. The temperature at the end plate of the extruder ranged between 97.6 and 141 °C, the absolute pressure was from 0.10 to 0.42 MPa, the mean retention time of material in the barrel was between 16 and 35 s, and the specific energy consumption was from 91.5 to 186.6 Wh/kg. According to the standard score, the optimum parameters for the reduction of the content of analysed mycotoxins were M = 24 g/100 g, FR = 25 kg/h, SS = 480 RPM, with a reduction of 3.80, 60.7, 61.5, 86.5, 47.7, and 55.9% for DON, 3-AcDON, 15-AcDON, HT-2, TEN, and AME, respectively. Under these conditions, the bulk density, pellet hardness, water absorption index, and water solubility index of the pellet were 0.352 g/mL, 13.7 kg, 8.96 g/g, and 14.9 g/100 g, respectively. Full article

Fruit seeds are often an underutilized side-stream of fruit processing. The most common approach to seed valorization is oil extraction due to the relative simplicity of the process. The partially or fully defatted seed meal is rarely further processed, even though seeds generally contain more protein and fiber than oil. The present study used single-screw extrusion (oil press), supercritical CO₂ extraction, and a combination of the two, to defat Japanese quince (Chaenomeles japonica) seeds, and evaluated the defatted meals as sources of functional protein. Defatting with oil press and CO₂ extraction proved similarly effective (reduced seed flour fat content from 11.75% to 6.40% and 5.32%, respectively); combining the two methods reduced fat content to 0.90%. The yield was minimally affected, but protein extract purity was defined by defatting efficiency (65.05% protein from non-defatted versus 82.29% protein from a combination-defatted meal). Defatting did not significantly affect amino acid composition but had a significant effect on every tested functional property (solubility, water, and oil binding capacity, apparent viscosity, foaming capacity, and emulsifying activity index). Of the tested defatting methods, supercritical CO₂ extraction and the combination provided the best results from most aspects. Full article

This work presents a comprehensive review of the evolution in modeling reactive extrusion (REx), tracing developments from early analytical models to advanced computational fluid dynamics (CFD) simulations. Additionally, it highlights the key challenges and future directions in this field. Analytical models to describe the velocity profiles were proposed in the 1950s, involving certain geometrical simplifications. However, numerical models of melt polymeric flow in extruders have proven to be crucial for optimizing screw design and predicting process characteristics. The state-of-the-art CFD models for single and twin-screw extruders design address the impact of geometry (type of mixing elements and geometrical simplifications of CFD geometries), pressure and temperature gradients, and quantification of mixing. Despite the extensive work conducted, modeling reactive extrusion using CFD remains challenging due to the intricate interplay of mixing, heat transfer, chemical reactions, and non-Newtonian fluid behavior under high shear and temperature gradients. These challenges are further intensified by the presence of multiphase flows and the complexity of extruder geometries. Future advancements should enhance simulation accuracy, incorporate multiphase flow models, and utilize real-time sensor data for adaptive modeling approaches. Full article

Waste streams from cereal-based food production processes, rich in organic matter and carbohydrates, have untapped potential for biogas production. This study uniquely investigated the extrusion-cooking process conditions, physical properties and biogas efficiency of snack pellets enriched with plant pomace (apple, chokeberry, pumpkin, flaxseed and nigella seeds) at different levels (10, 20 and 30%), produced using a single-screw extruder-cooker. The highest efficiency obtained in the extrusion-cooking process (18.20 kg/h) was observed for pellets with the addition of 30% flaxseed pomace. The SME value during the entire process was in the range of 0.015–0.072 kWh/kg. New insights into the interaction between the inclusion of pomace, the physical properties of the extrudate and the anaerobic fermentation efficiency were obtained. The results show that 30% chokeberry extrudate maximized methane production (51.39% gas), demonstrating a double innovation: improving snack pellet quality and converting food waste into renewable energy. Full article