Higher Screw Speed Research Articles

Investigating extrusion impact on functional, textural properties, morphological structure, and molecular interactions in hulless barley-based extruded snacks supplemented with mung bean.

The effect of varying extrusion conditions on the functional properties of hulless barley-mung bean (70:30) extruded snacks was investigated using response surface methodology with feed moisture (FM), barrel temperature (BT), and screw speed (SS) as process variables. Results revealed significant impacts on functional characteristics with varying extrusion conditions. Bulk density (BD) of extruded snacks ranged from 0.24 to 0.42 g/cm3, showing that lower FM and higher BT results in lower BD while it increased with increasing FM, SS, and BT. The expansion ratio (ER) of extruded snacks ranged between 2.03 and 2.33, showing BT and SS had a desirable positive effect, whereas increasing FM led to decreased ER. Increasing BT and SS depicted a negative effect on water absorption index, whereas FM showed positive effect, which ranged between 4.21 and 4.82 g/g. A positive effect on water solubility index was depicted by BT and SS, which ranges between 9.01% and 13.45%, as higher SS and BT led to starch degradation and increased solubility suggesting better digestibility. The hardness of extruded snacks ranged from 32.56 to 66.88 Newton (N), showing increasing FM increased hardness, whereas higher SS and BT resulted in lowering the hardness. Scanning electronic microscope (SEM) analysis revealed structural changes in extrudates in comparison with nonextruded flour, indicating starch gelatinization and pore formation affected by varying processing parameters. Shifts in absorption bands were observed in Fourier transform infrared spectroscopy (FT-IR), suggesting structural changes in starch and protein. Understanding the effects of extrusion parameters on product properties can help tailored production to meet consumers' preferences and the development of functional snacks with improved nutritional quality.

Extrusion-controlled lipid retention and distribution of wheat germ and its application combining exogenous starch

Wheat germ is an agricultural but low-economic by-product for animal feed or waste due to its susceptibility of hydrolytic/oxidative rancidities. Here, we use controllable extrusion to treat wheat germ, and with assistance of exogenous starch as lipid protective factor at different ratios (0:10 2:8, 3:7, 4:6). Oxidation of optimized germ extrudate was slowed down during storage, with total lipid retention rate reach up to ∼88.3%. Extrusion dynamic analysis showed that relatively high screw speed (100–150 rpm) significantly shortened mean residence time, increased axial diffusion velocity and reduced the loss of free and bound lipid. Type Ⅱ starch-lipid complex was changed to type Ⅰ during extrusion, with thermal transition peak declined. Wheat germ lipid was most evenly distributed under 100 rpm extrusion. The hydrogen bonding interaction between exogenous starch and lipids in wheat germ was strengthened, with significant modification in water absorption, water solubility, expansion and textual indexes.

Antioxidant potential and chemical composition of new generation extruded snack pellets supplemented with fresh broccoli addition

Abstract The therapeutic potential of broccoli has been highlighted by its function in the prevention of cancer, diabetes and other diseases. As a result, there is a great deal of interest in creating innovative functional foods supplemented with broccoli. In the extrusion-cooking process, raw materials based on potato mixes with the addition of fresh broccoli (Brassica oleracea L. var italica, Brassicaceae) were used to create new generation extruded snack pellets. A prototype single screw extruder-cooker with L/D=20 was utilized, and various processing conditions (screw speed 60 and 100 rpm, as well as either 32 and 36% levels of initial moisture content) were applied. Mixtures of 10% and 30% fresh broccoli contents were investigated. The final snack pellets obtained under such processing conditions were determined for their antioxidant potential, polyphenols, proximate composition and fatty acids profile. We found that in the presence of fresh broccoli in blends, higher screw speed and higher moisture content allowed obtaining (in most samples) a higher polyphenal content in the resulting pellets. Over all, the antioxidant potential of snack pellets increased with the addition of fresh broccoli. Pellets with 30% addition of the broccoli processed at screw speed 100 rpm at moisture content of 32% displayed the highest total polyphenols content and highest antioxidant activity. Moreover, such samples demonstrated notable increase in the content of total protein, crude ash, as well as MUFA and PUFA in the total amount of fatty acids.

The influence of material properties and process parameters on energy consumption during extrusion of flexible PVC

The aim of this work is to investigate the correlation between the process settings, the material properties, and the extrusion energy consumption. Experiments were conducted on a laboratory extruder, testing different flexible PVCs. During continuous single-screw extrusion for various process conditions, power signals were recorded for the extruder's motor and the entire machine. According to the results of the previous works, the absorbed current, the power factor, and the total active power increased with the screw speed for all the tested materials. However, due to the high content of additives, the considered materials exhibited wall-slip during extrusion, and the influence of the slip behavior on the specific energy consumption was evaluated too. It was found that the specific energy consumption did not decrease monotonically with the screw speed, and thus the maximum energy efficiency can not always be achieved at the highest screw speed. Significant correlations were found between the material's hardness, viscosity, and process energy usage, with the hardest and most viscous materials requiring more energy to be extruded.

Degradation of starch in pasta induced by extrusion below gelatinization temperature.

The structural deformation of starch during pasta extrusion leads to varied effects on pasta quality. We investigated the impact of shearing force on the starch structure of pasta and pasta quality by varying the screw speed (100, 300, 500 and 600rpm) with a temperature range of 25 to 50 ℃ in increments of 5 ℃, from the feeding zone to the die zone. The higher screw speeds were associated with more specific mechanical energy input (157, 319, 440, and 531kJ/kg for pasta produced at 100, 300, 500 and 600rpm, respectively), resulting in a lower pasting viscosity (1084, 813, 522 and 480mPa·s for pasta produced at 100, 300, 500 and 600rpm, respectively) in the pasta due to the loss of starch molecular order and crystallinity. Size-exclusion chromatography revealed that pasta produced at 600rpm screw speed had a lower amylopectin size distribution which indicated molecular breakdown during extrusion. Pasta produced at 600rpm had higher in vitro starch hydrolysis (both raw and cooked) than the pasta made at 100rpm. The research provides relationship of how the screw speed can be manipulated to design pasta with varied texture and nutritional functionality.

Application of Edible Insect Flour as a Novel Ingredient in Fortified Snack Pellets: Processing Aspects and Physical Characteristics

The aim of the study was to develop a suitable recipe for wheat-corn snack pellets fortified with insect flour addition and to evaluate the relevant processing aspects and physical characteristics of the developed products. Varying levels of edible insect flour (10, 20, and 30%) were incorporated into a new type of fortified snack pellet as a half product for further expansion. The effects of the edible insect flour level, as well as processing variables (moisture levels 32, 34, 36% and screw speeds 60, 80, 100 rpm), were analyzed on the extrusion stability and on selected snack pellets’ physical properties processed via single-screw extrusion cooking. This research indicated that an increasing amount of edible insect flour significantly affected the processing output and energy consumption. The incorporation of insect flour in blends significantly increased the specific mechanical energy and efficiency of pellet extrusion, especially at a high moisture level and high screw speed during processing. Moreover, the addition of insect flour in the snack pellets significantly reduced the bulk density and pellet durability. Principal component analysis confirmed that approximately 76.5% of the data variance was explained by the first two principal components, and significant correlations were noted between the properties of the tested snack pellets. It can be concluded that up to 20% of insect flour in newly developed extruded snack pellet formulations has no negative effect on processing and physical properties.

Continuous Manufacturing of Solvent-Free Cyclodextrin Inclusion Complexes for Enhanced Drug Solubility via Hot-Melt Extrusion: A Quality by Design Approach.

Conventional cyclodextrin complexation enhances the solubility of poorly soluble drugs but is solvent-intensive and environmentally unfavorable. This study evaluated solvent-free hot-melt extrusion (HME) for forming cyclodextrin inclusion complexes to improve the solubility and dissolution of ibuprofen (IBU). Molecular docking confirmed IBU's hosting in Hydroxypropyl-β-cyclodextrin (HPβ-CD), while phase solubility revealed its complex stoichiometry and stability. In addition, an 11 mm twin-screw co-rotating extruder with PVP VA-64 as an auxiliary substance aided the complex formation and extrusion. Using QbD and the Box-Behnken design, we studied variables (barrel temperature, screw speed, and polymer concentration) and their impact on solubility and dissolution. The high polymer concentration and high screw speeds positively affected the dependent variables. However, higher temperatures had a negative effect. The lowest barrel temperature set near the Tg of the polymer, when combined with high polymer concentrations, resulted in high torques in HME and halted the extrusion process. Therefore, the temperature and polymer concentration should be selected to provide sufficient melt viscosities to aid the complex formation and extrusion process. Studies such as DSC and XRD revealed the amorphous conversion of IBU, while the inclusion complex formation was demonstrated by ATR and NMR studies. The dissolution of ternary inclusion complexes (TIC) produced from HME was found to be ≥85% released within 30 min. This finding implied the high solubility of IBU, according to the US FDA 2018 guidance for highly soluble compounds containing immediate-release solid oral dosage forms. Overall, the studies revealed the effect of various process parameters on the formation of CD inclusion complexes via HME.

Optimisation of extrusion conditions for production of antioxidant-rich extruded breakfast cereals from purple sweet potato (Ipomoea batatas L.) and red rice using response surface methodology

Purple sweet potato powder (PSPP) is rich in anthocyanins and other polyphenols that provide excellent antioxidant and other biological activities with potential health benefits. In the present work, the response surface methodology (RSM) was used to optimise the extrusion processing conditions to develop healthy breakfast cereals. The independent variables studied included barrel temperature, screw speed, and feed moisture. The linear terms of barrel temperature and feed moisture content were found to be the significant (p < 0.05) factors affecting the product's functional and physicochemical properties. The expansion property of extrudate significantly (p < 0.001) increased at low temperature, high screw speed, and low feed moisture. The recommended optimum extrusion conditions of barrel temperature, screw speed, and feed moisture content were at 157.0°C, 126.0 rpm, and 13.0%, respectively; and under these optimum conditions, significantly high retention (75.0%) of anthocyanin content was detected. Furthermore, scanning electron micrographs depicted that the optimised breakfast cereals had a better cell structure with smoother and thinner cell walls than the non-optimised samples.

Study of the feeding performance of mesoporous silica in a loss-in-weight feeder

Accurate and reliable continuous feeding is essential for the continuous manufacturing of solid-dose pharmaceuticals to ensure the reproducible composition of the final product. Consistent feeding of cohesive powders is challenging and requires an understanding of the interplay between material properties and feeder configuration. This study presents the volumetric and gravimetric feeding behaviour of a cohesive pharmaceutical, excipient mesoporous silica, at low feed rates (< 0.6 kg/h) using a twin-screw loss-in-weight feeder. The study investigates how the screw pitch, screen type and gravimetric setpoint impact the feed factor and feed rate variability. Additionally, the flow function and bulk density of the fed and unfed silica samples were determined and related to the feeding process parameters. Volumetric experiments highlight inconsistent feed due to the poor screw flight filling at high screw speeds and for configurations with the larger pitch, coarse concave screw. Poor screw flight filling also resulted in an inverse relationship between screw speed and feed factor in volumetric mode. In gravimetric mode, feed variability, expressed as %RSD, was greatest at the lower gravimetric setpoints with minimal impact due to tooling configuration. Discharge screen set-up was identified as the parameter which had a significant effect on the bulk density and flowability of the powder post-feeding.

The Physical Properties of High‐Quality Proteins Expanded Extrudates Made from Corn Meal, Chickpea Flour, and Yellow Pea Concentrate

AbstractThis study is carried out to produce high‐quality protein expanded extrudates from degermed corn meal–chickpea flour (DCM–CPF) blends and DCM–yellow pea concentrate (DCM–YPC) blends via a twin‐screw extruder. The effect of barrel temperature and screw speed (SS) on the DCM and DCM–CPF, DCM–YPC ratios and feed moisture content (16%–20%) on expansion are determined. The higher SS and barrel temperature decrease hardness and increase specific mechanical energy (SME), and all viscosities reduce compared to raw material for DCM extrudates. When SS is at 550 rpm and barrel temperature at 130°C, the higher legume addition decreases specific longitudinal expansion (SLE), expansion ratio (ER), all viscosities and increases hardness, piece density (PD), for all extrudates. The increasing of feed moisture content from 16% to 20% resulted in the PD and hardness increases significantly (p &lt; 0.05) and SME, SLE, ER, peak viscosity (PV) values decrease for DCM–CPF extrudates, whereas SLE, hardness, PV values increase, ER decreases and there is no significantly change in PD for DCM–YPC extrudates. As compared to DCM–CPF‐III, DCM–YPC‐III exhibits better expansion with higher in vitro protein digestibility corrected amino acid score (IV‐PDCAAS) and PD per serving (30 g).

Relation between injection molding conditions, fiber length and mechanical properties for highly reinforced long fiber polypropylene

AbstractA complete study on the relation between the injection molding parameters and the resulting fiber length, orientation and mechanical properties is presented for highly reinforced long fiber thermoplastic (LFT) polypropylene (PP). It has been found that the longest fibers obtained are the ones processed with the lowest backpressure and the highest screw speed. The backpressure gains importance over screw speed when the amount of glass fiber reinforcement increases, contrary to what was found for less reinforced thermoplastics. The injection speed does not influence the fiber breakage phenomena, while it has great importance in fiber orientation and thus on the tensile strength, especially when the weight fiber average length is below 1000 μm. When this average is over 1000 μm, fibers begin to weave a mesh that thickens the core region and hinds its orientation, reducing the tensile strength but improving impact resistance.

Optimising Starch Transformation in Aquafeed Extrusion for Enhanced Water Stability and Performance

The physical quality of aquafeed pellets is paramount for the health and performance of aquatic species in aquaculture systems. Starch, a small, but necessary component of aquafeed, plays a crucial role in creating durable and water-stable pellets. This paper investigates the complex relationship between starch transformation during extrusion cooking and its influence on water stability. Through a series of experiments involving various extrusion parameters, including three melt moisture levels and three screw speeds, the study reveals that the key to producing water-stable aquafeed lies in optimizing starch gelatinization and minimizing dextrinization. High screw speeds, in conjunction with moderate to high melt moisture levels, facilitate starch gelatinization while avoiding dextrinization, resulting in pellets with superior water stability. Conversely, low melt moisture levels at any screw speed or any melt moisture at low screw speeds lead to poor water stability due to increased dextrinization or suboptimal gelatinization levels. The research also underscores the critical role of the glass transition of starch. Starch in its semi-crystalline state is found to be more susceptible to shear degradation during extrusion. Therefore, rapidly elevating the raw material's temperature above its glass transition temperature is crucial for achieving water-stable aquafeed.

Protein Quality of Extruded Ready-to-Eat Baby Foods from Orange-Fleshed Sweet Potato, Amaranth Seeds, and Soybean Flour Blends

Purpose: Protein quality refers to the total protein content, essential amino acid content, and digestibility of a protein. Source, bioavailability, food matrix, and processing conditions all have an impact on protein quality. Protein quality can be lost during food processing. This study was carried out to investigate the effect of extrusion cooking and blend proportions on the protein quality of extruded ready-to-eat baby foods.&#x0D; Methodology: Different blends of orange-fleshed sweet potato, amaranth seeds, and soybean flour were used and analyzed for protein quality including in vitro protein digestibility (IVPD) of extruded ready-to-eat baby foods. In addition, nutrient damage due to heat or processing temperature was evaluated by analyzing available lysine in the end products to ensure the quality of extruded ready-to-eat baby foods. Extrusion cooking was carried out at a temperature of 90oC, screw speed of 400 rpm, and feed moisture content of 35%.&#x0D; Findings: The results showed that IVPD ranged from 54.05 to 91.87%. The available lysine as a parameter to evaluate the nutritional damage due to thermal processing ranged from (1.69 to 2.79%). This research predicts the potential availability of highly digestible protein as well as the assurance of lysine availability once extrudates are consumed. Achieving high lysine retention during extrusion cooking depends on a number of factors, including low temperature, high screw speed, high feed moisture content, and high shear forces that lead to a short residence time.&#x0D; Recommendation: It is important to conduct more research on how extrusion cooking affects the molecular and physical interactions between starches, proteins, lipids, and phenolic compounds.

Bioactive, Mineral and Antioxidative Properties of Gluten-Free Chicory Supplemented Snack: Impact of Processing Conditions.

This study aimed to investigate the impact of chicory root addition (20-40%) and extrusion conditions (moisture content from 16.3 to 22.5%, and screw speed from 500 to 900 rpm) on bioactive compounds content (inulin, sesquiterpene lactones, and polyphenols) of gluten-free rice snacks. Chicory root is considered a potential carrier of food bioactives, while extrusion may produce a wide range of functional snack products. The mineral profiles were determined in all of the obtained extrudates in terms of Na, K, Ca, Mg, Fe, Mn, Zn, and Cu contents, while antioxidative activity was established through reducing capacity, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) tests. Chicory root addition contributed to the improvement of bioactive compounds and mineral contents, as well as antioxidative activities in all of the investigated extrudates in comparison to the pure-rice control sample. An increase in moisture content raised sesquiterpene lactones and minerals, while high screw speeds positively affected polyphenols content. The achieved results showed the important impact of the extrusion conditions on the investigated parameters and promoted chicory root as an attractive food ingredient in gluten-free snack products with high bioactive value.

Study on the Extrusion Molding Process of Polylactic Acid Micro Tubes for Biodegradable Vascular Stents.

Polylactic acid (PLA) has been widely used in the field of medical devices. However, few studies have been conducted on the extrusion molding of PLA micro tubes for the preparation of biodegradable vascular stents. In this paper, the extrusion die for PLA single-cavity micro tubes was designed and manufactured by micro-extrusion theory. Taking the outer diameter, wall thickness, wall thickness uniformity and ovality of micro tubes as the evaluation index, the influence of the main extrusion process parameters on the evaluation index was studied. The experimental results show that the outer diameter and wall thickness are significantly affected by screw speed, pulling speed and gas flow rate; extrusion process parameters have little influence on wall thickness uniformity and ovality within a certain range, which mainly depends on the processing accuracy and assembly accuracy of the extrusion die. However, excessively high screw speed and low gas flow rate have significant effects on ovality. Finally, according to the influence of extrusion process parameters on the evaluation index, a series of micro tubes that meet the design requirements are extruded and carved into vascular stent structures.

Microstructure development analysis of long-glass-fiber-reinforced polypropylene in injection molded spiral-flow

The research focuses on the fiber behavior following injection molding on a spiral-flow mold, particularly its fiber orientation behavior. The behavior of the glass fiber will be examined by altering key experiment settings, the screw speed and the back pressure, and employing different melt paths. The results show that the application of high back pressure and high screw speed decreased the fiber length but successfully increased the fiber orientation average to the flow direction. The design of the melt flow paths that employed here are showing imbalance mold filling phenomena that resulting asymmetric fiber orientation hierarchy. Meanwhile, with the combination of correct settings in the experimental parameters and the right choice of melt flow path can create a very high tensor value with more than 80% fibers aligned to the flow direction.

Effects of Sacha inchi (Plukenetia volubilis L.) oil and extrusion process conditions on physicochemical properties of fortified omega‐3 fibrous high moisture meat analogs

AbstractHigh‐moisture meat analogs (HMMA) fortified with omega‐3 from Sacha inchi (Plukenetia volubilis L.) oil were developed using Box–Behnken design and response surface methodology (RSM), with oil content (X1) 5–9%, screw speed (X2) 320–380 rpm, and feed moisture content (X3) 55–75%. Results showed that adding oil reduced the pasting properties and water absorption index of the ingredients. On tearing, HMMA showed a parabolic fibrous pattern. Increasing screw speed at low moisture content resulted in a darker product, while increased oil and feed moisture content gave a softer texture, with screw speed at lowest feed moisture content producing the opposite result. HMMA produced at high screw speed presented numerous micro‐porous structures. Increased oil content significantly decreased cooking yield, while oil added at up to 9% produced 1.33 g omega‐3/100 g HMMA.Novelty impact statement Balancing oil addition and extrusion process conditions produced the desired HMMA fortified with omega‐3. Increased oil and feed moisture content caused soft HMMA, while screw speed at different feed moisture levels impacted microstructural alignment. Sacha inchi oil added at up to 9% gave 1.33 g omega‐3/100 g HMMA.

Impact of Melt Processing Conditions on the Degradation of Polylactic Acid.

To reduce the degradation of polylactic acid (PLA) during processing, which reduces the molecular weight of PLA and its properties, prior studies have recommended low processing temperatures. In contrast, this work investigated the impact of four factors affecting shear heating (extruder type, screw configuration, screw speed, and feed rate) on the degradation of PLA. The polylactic acid was processed using a quad screw extruder (QSE) and a comparable twin screw extruder (TSE), two screw configurations, higher screw speeds, and several feed rates. The processed PLA was characterized by its rheological, thermal, and material composition properties. In both screw configurations, the QSE (which has a greater free volume) produced 3–4 °C increases in melt temperature when the screw speed was increased from 400 rpm to 1000 rpm, whereas the temperature rise was 24–25 °C in the TSE. PLA processed at low screw speeds, however, exhibited greater reductions in molecular weight—i.e., 9% in the QSE and 7% in the TSE. Screw configurations with fewer kneading blocks, and higher feed rates in the QSE, reduced degradation of PLA. At lower processing temperatures, it was found that an increase in melt temperature and shear rate did not significantly contribute to the degradation of PLA. Reducing the residence time during processing minimized the degradation of PLA in a molten state.

Integrated numerical simulation and quality attributes of soybean protein isolate extrusion under different screw speeds and combinations

A numerical simulation of the fluid-dynamic parameters (shear rate distribution, shear viscosity distribution and residence time) inside the barrel combined with extrudate properties, is a potential novel approach for investigating molten soybean protein isolate (SPI) under different screw speeds and combinations. Through finite element simulation, computer fluid dynamics and particle tracking simulation analysis, it was found that increasing the screw speed can increase the shear rate, decreased the shear viscosity of the SPI fluid, and reduced the RDT, thereby promoting the dispersion degree. The maximum shear rate and minimum shear viscosity were generated at the screw flight flanks, and the fluid underwent an alternate shearing force in the barrel. A small axial channel width can significantly promote the fluidity of molten proteins. In conclusion, SPI extrudates with a homogenous structure, smooth surface, and favourable colour and textual profile were produced at a relatively high screw speed (140 rpm).

Fabrication and Property Characterization of Long-Glass-Fiber-Reinforced Polypropylene Composites Processed Using a Three-Barrel Injection Molding Machine.

Processing equipment and parameters will highly influence the properties of long-fiber-reinforced injection-molded thermoplastic composites, leading to different fiber lengths and orientations. Thus, maintaining fiber length during the injection molding process is always a big challenge for engineers. This study uses long-glass-fiber-reinforced polypropylene with 25 mm fiber length and a special-built novel injection molding machine with a three-barrel injection unit, including a plasticizing screw, an injection plunger, and a packing plunger, to fabricate injection molding parts while retaining long fiber length. This study also discusses the influence of process parameters, such as back pressure, screw speed, melt temperature, and different flow paths, on the properties of long-glass-fiber-reinforced composites. The experiment results show that a higher screw speed and back pressure will reduce the fiber length in the injection-molded parts. However, using appropriate parameter settings can maintain the fiber length to more than 10 mm. It was found that by increasing the back pressure, the cross direction of the fiber orientation can be increased by up to 15% and the air trap volume fraction can be decreased by up to 86%. Setting appropriate back pressure under a low screw speed will increase the tensile strength. Finally, it was found that the single-edge-gate path results in a higher tensile strength than that of the single-sprue-gate path due to the retainment of longer fiber length in the injection-molded part.