Co-rotating Twin Screw Extruder Research Articles

Durable polymer composites preparation with oxy-delignified banana fiber for automotive parts: A study on mechanical and thermal properties

An innovative process route has been developed to produce modified banana fiber that are used as reinforcement in polypropylene composites for automotive parts. Banana fiber (BF) is modified through, Alkaline peroxide (APF), and oxygen delignification (ODF) treatment to obtain better adhesion and enhanced thermo-mechanical properties. The fiber-reinforced polymer (FRP) composites (10–30 % loading), were prepared through a specified configuration in a co-rotating twin screw extruder followed by injection molding. The results show that the ODF treatment with a 15 % NaOH concentration resulted in an 11-kappa number, which was lower than APF and untreated fiber. The highest improvement in tensile (31.27 ± 2.56) and flexural strength (44.880 ± 1.05 MPa) was achieved for ODF polymer composite and were 20.40 % and 35.6 % higher compared to the untreated fiber. The addition of natural fiber decreased the melt flow index to 7.56 gm/10 min with a slight decrease in hydrophilicity. The thermal stability was increased with enhanced melting, crystallization temperatures, and surface morphology.

Analysis of the Dispersive and Distributive Mixing Effect of Screw Elements on the Co-Rotating Twin-Screw Extruder with Particle Tracking.

Compounding is an important step in processing base polymers and is used to incorporate various additives into a polymer. For this purpose, different screw elements are used for dispersive and distributive mixing on a co-rotating twin-screw extruder. Optimising the screw configuration requires precise knowledge of the screw elements' mixing properties, which have not been thoroughly investigated. This study analyses the mixing behaviour of individual screw elements regarding dispersive and distributive mixing using 3D CFD flow simulations with subsequent particle tracking. For distributive mixing, the particle distribution behind the screw elements in the XY plane is analysed and the mixing index MQ, which relates the standard deviation and the mean value of the triangular areas between the particles, is calculated. For dispersive mixing, the maximum shear stress on the particle path and the integral of the shear stress over the residence time of each individual particle are determined. The results show that screw element geometry and rotation speed have a significant influence on dispersive and distributive mixing. In addition, better dispersive mixing is achievable with highly viscous materials. These findings enable the optimisation of the mixing zone of a co-rotating twin-screw extruder for the efficient mixing of mineral fillers.

Identifying the location and micellization of PEG-b-PCL multiblock copolymers in PLA/PCL blends via AFM nanoscale IR spectroscopy

The IR absorption mapping of two multiblock copolymers based on poly(ethylene glycol) and poly(ε-caprolactone) segments (PEG-b-PCL) in poly(acid lactic) and poly(ε-caprolactone) blends (PLA/PCL) was performed via AFM nanoscale IR spectroscopy. These copolymers, having the same number average molar masses (Mn‾) but varying block sizes, were added into the blend in different amounts (1 and 5 wt%) using a co-rotating twin-screw extrusion. The results revealed that copolymers with smaller blocks are preferentially located near the interface when incorporated in small quantities. Increasing the copolymer content led to preferential diffusion into the PLA matrix. Compatibilization with the longer block-size copolymers also led to preferential diffusion in the PLA matrix, albeit with a tendency to form micelles. This hampers the overall mechanical properties of the blend, making the compatibilized blend more brittle than neat PLA. Compatibilization with the short block-size copolymers showed no micellization and improved the mechanical behavior of PLA/PCL.

Experimental and numerical characterization of screw elements used in twin-screw extrusion

Hot melt extrusion by a co-rotating twin screw extruder is an important process in the pharmaceutical industry. Especially for quality by design aspects, a comprehensive process understanding is indispensable. The performance of conveying elements was determined as critical process parameter, and therefore an experimental and numerical framework was developed to analyze and compare variations. A test rig capable of measuring volume flow, pressure and torque with high accuracy and precision was designed and built. The 3D simulation was performed using computational fluid dynamics (CFD). A stationary model with impulse transmission and an apparent motion of the screws was applied. The experimental data were fitted to the model of Pawlowski, and parameters for the pressure (A1, A2) and power characteristics (B1, B2) were determined. Good agreement between experimental data and the model was observed. The simulation was significantly faster compared to common methods, and the results were consistent with the literature. Systematic investigations of a native and worn screw were performed with CFD resulting in a transport capacity increase and a pressure build up decrease for all tested screw elements. An experimental and simulation setup was generated to assess the performance of co-rotating twin screw elements. The experiments provided high-quality data, and the simulations exhibited high flexibility with low computational effort.

Fabrication of biopolyethylene-based biocomposites with coffee ground waste: Effect of polyethylene-graft-maleic anhydride

The production of plastic products from non-renewable raw materials, such as petroleum, damages the environment. Consequently, biocomposites have aroused interest from industry and researchers due to their ecologically correct characteristics, mainly because they come from renewable sources. Therefore, this study aimed to produce biopolyethylene/coffee ground waste (BioPE/CGW) biocomposites and analyze the impact of CGW and polyethylene-graft-maleic anhydride (PE-g-MA) on BioPE. The biocomposites were prepared in a co-rotational twin-screw extruder equipped with a side feeder to feed the CGW. The materials were subsequently injection molded to produce the impact, tensile, and HDT samples. The temperature profiles used during extrusion and injection were between 170 and 180°C. The BioPE and biocomposites were investigated for the vibrational (Infrared Spectroscopy - FTIR), thermal (differential scanning calorimetry), mechanical (tensile, impact, and hardness), thermomechanical (heat deflection temperature (HDT) and Vicat softening temperature (VST)), and morphological (scanning electron microscopy (SEM)) properties. The compatibilizer improved the interface between phases, promoting mechanical and thermomechanical improvements in the biocomposites. PE-g-MA promoted increments in tensile strength and elastic modulus of up to 38% and 25% in the BioPE/CGW30 and an increase of 44% in the elastic modulus compared to BioPE. The thermomechanical investigations showed that HDT increased by 8.8 and 3.3°C and VST increased by 2.5 and 6.6°C compared to BioPE and the BioPE/CGW30, respectively. Biocomposites from renewable and biodegradable sources align with a sustainable development concept.

Mixing performance in an asymmetrical non-twin kneading element channel

Abstract The kneading elements play a crucial role in the distributive and dispersive mixing in the conventional co-rotating twin screw extruders. A novel kind of asymmetrical dual-speed co-rotating non-twin kneading elements (NTKE) with a zero staggered angle was designed to introduce symmetry break to improve mixing. Finite element method was applied to solve the time-dependent flow field where mesh superposition technique was used to impose the boundary conditions of moving parts and further to avoid the remeshing at every time steps. The flow and mixing of several fluids obeying the Carreau constitutive model with the different power law exponents were investigated numerically and compared with the conventional co-rotating twin kneading elements (TKE). Distributive mixing was evaluated through evolution of tracer droplets and decaying of variance index with time. Moreover, the dispersive mixing was examined in terms of the statistical distributions of mixing index. An integral function with regard to the mixing index was proposed to evaluate the proportion of tracer particles subjected to the elongation.

Cysteine, sodium metabisulfite, and glutathione enhance crosslinking between proteins during high moisture meat analog extrusion processing and may improve the fibrousness of the products.

High moisture meat analog (HMMA) products processed using extrusion have become increasingly popular in the last few years. Because the formation of disulfide bonds is believed to play a critical role in the texturization mechanism, this study aimed to understand how chemical compounds capable of reducing disulfide bonds, specifically cysteine, sodium metabisulfite, and glutathione, affect the texture and the chemical interactions between the proteins. Wheat protein blended with cysteine, sodium metabisulfite, or glutathione at levels of 0, 0.5, 1.0, 2.5, 5.0, and 7.5 g kg-1 was extruded at three different temperatures (115, 140, and 165 °C) using a co-rotating twin-screw extruder. The feed rate (85 g min-1), the moisture content (600 g kg-1), and the screw speed (300 rpm) were kept constant. Unextruded and extruded material was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, polymeric protein fractionation, and sulfhydryl group/disulfide bond analysis. Extruded samples were further analyzed for their hardness and their anisotropic index. The inclusion of reductants significantly affected the structure of the obtained extrudates. Although reducing agents had a relatively small impact on the total amount of disulfide bonds, their action significantly enhanced crosslinking between the proteins. At select conditions, samples with high fibrousness were specifically obtained when cysteine or sodium metabisulfite was included at levels of 5.0 g kg-1. In the presence of reducing agents, it is believed that disulfide bonds are split earlier during the process without binding to them, giving the protein strands more time to unravel and align, leading to a better flow behavior and more fibrous products. © 2024 Society of Chemical Industry.

Modelling supercritical CO2 flow in a co-rotating twin screw extruder using the level-set method

Supercritical CO2 has been used in recent years to replace conventional blowing agents in extrusion processes. So far, computational fluid dynamics analyses of such extrusion processes are relatively scarce. In this work, a multiphase model of a co-rotating twin screw extruder is presented that uses the level-set method to describe the interface between supercritical CO2 and polypropylene - which is modelled as an inelastic, non-Newtonian fluid - under various operating conditions. The results show that the level-set method is a promising technique to describe multiphase flow and can predict both stable and unstable processing regimes as described by experimentalists in literature.

Effect of Coupling Agent on the Properties of Pineapple Leaf Fiber/ Polypropylene Composite

Natural fibre matrix composites have been utilized in numerous industries, including the automotive, construction, and aerospace sectors. Maleic anhydride grafted polypropylene (MAPP) was used in this study to examine the effect of the coupling agent on the properties of a composite-produced using pineapple leaf fibre. The weight ratios of pineapple leaf fibre, polypropylene, and MAPP were 20g:180g, 15g:180g:5g, and 10g:180g:10g, respectively. The materials were mixed using a co-rotating twin-screw extruder machine at 170 °C and 50 rpm. The composite was then manufactured by injection molding at 185 °C. The mechanical and physical properties of PALF composite were examined by using a tensile test, impact test, and water absorption test. Thermal Gravimetric Analysis (TGA) was used to characterize the thermal properties of PALF/PP, and PALF/PP/MAPP composite. The surface morphology and fracture surface of the composite was characterized by using Scanning Electron Microscopy (SEM). Compared to the composite containing 5 g of MAPP, the tensile strength composite containing 10 g of MAPP produced a stronger interfacial bond. According to the impact test, adding more MAPP increases the material's strength and stress transmission. The average percentage of water absorption indicates low water absorption after the addition of the coupling agent. It can be concluded that the addition of a coupling agent improved the composite's properties.

Influence of γ-Irradiation on the Electronic Structure and the Chemical and Mechanical Properties of Poly(hydroxybutyrate-valerate)/Poly(caprolactone) Blends: Insights from Experimental Data and Computational Approaches

In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density functional theory (DFT) and the time-dependent DFT (TD-DFT) methods were used together with a model containing four monomer units to provide an insight into the electronic structure, chemical bonds, and spectroscopic (such as Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis)) properties of PHBV and PCL blend phases, which are critical for predicting and designing new materials with desired properties. We found that an increase in γ-irradiation doses caused splitting instead of crosslinks in the polymer chains, which led to evident deformation and an increase in tensile strength at break of 2.0 to 5.7 MPa for the PHBV/PCL blend. Further, this led to a decrease in crystallinity and proved the occurrence of a more favorable interaction between the blend phases.

Manufacturing and Characterization of Three Modified Vegetable Oil–Added Polylactic Acid Composites

Polylactic acid (PLA) was modified with three types of modified vegetable oils (MVOs), which are the epoxidized soybean oil (ESBO), maleinized sunflower oil (MSO), and maleinized olive oil (MOO), at different weight fractions. A corotating twin screw extruder was used to produce composite materials by the melt‐mixing process. The effect of MVO content, from 2.5% to 10%, on the morphology, mechanical properties, density, and water absorption was investigated in detail. The addition of ESBO and maleinized vegetable oils leads to a slight decrease in the density of PLA from 1.252 to 1.231 g/cm3. As the concentration of MVO in PLA increases, the amount of water absorption also increases, and the highest water absorption value was observed in P10MSO. The FTIR spectra of all concentrations of the MOO and MSO have two peaks at 1781 and 1861 cm−1, attributed to the C=O stretching which is related to maleic acid copolymerization. In general, the elastic modulus (EM) was slightly changed by the addition of MVOs to PLA, while the tensile strength (TS) decreased. Due to the plasticizing effect of MVOs, an increase in the Izod impact strength was obtained.

Reactive processing-microstructure-mechanical performance correlations in biodegradable poly(lactic acid)/expanded graphite nanocomposites.

Reactive extrusion is a promising method to prepare biodegradable nanocomposites with enhanced modulus, strength and toughness. In this study, biodegradable extended nanocomposites based on poly(lactic acid) (PLA)/expanded graphite (EG) were prepared by melt-compounding using a co-rotating twin-screw extruder. Effects of EG loading, aspect ratio, delamination and dispersion state on the mechanical and thermo-mechanical properties of PLA/EG nanocomposites were investigated. Adding the largest EG (EGL) nanoplatelets, having the average particle size of 48.2 μm and aspect ratio of 19.5, to the PLA matrix enhanced the Young modulus, tensile strength, ultimate strain and tensile toughness of the extended PLA sample with benzoyl peroxide (BP) between 40-100%. The observed enhancements originated from restricted PLA molecular motions, assisted PLA crystallization and intensified BP activity in extending the PLA chains. In contrast, EG nanofiller (EGS), with the lowest aspect ratio and size, lowered the PLA relaxation time and accelerated the PLA crystallization. This type of EG showed the weakest reinforcing effect on PLA. For the EG type (EGM) with an intermediate size and aspect ratio, it was observed that the presence of the nanoparticles had a negligible effect on the PLA molecular dynamic and reduced the PLA crystallization rate. The highest impact strength was observed for the PLA/EGM nanocomposite at 1 phr loading.

Aynı Yöne Dönen Çift Vidalı Ekstrüderli Tandem Bir Termoplastik Geri Dönüşüm Sisteminde Vida Yapılanmasının İncelenmesi

Polymers have rapidly replaced the utilization of glasses, ceramics, metals, and organic textiles due to their cost-effectiveness, lightweight nature, and enhanced functionality. Nevertheless, as a consequence of their chemical composition, polymers undergo a protracted degradation process in natural environments, resulting in a significant accumulation of plastic waste since their inception. This accumulation has now reached a critical threshold, posing a substantial risk to both human well-being and the preservation of natural ecosystems. In the recycling process of thermoplastic wastes, it is necessary to subject them to two rounds of melting in order to obtain compounds. This practice results in a reduction of the recycling numbers associated with thermoplastics, which possess a finite recycling lifespan, by 50%. The present work involved the construction of a tandem recycling process, wherein molten waste polymers were immediately introduced into a co-rotating twin screw extruder. In contrast to alternative approaches, a process-dependent screw configuration has been devised for the twin-screw system employed in the delivery of molten material. The product derived from 80% waste thermoplastic was thereafter compared to the original product as an outcome of the aforementioned procedure. Properties similar to those of pure Polypropylene were seen in some physical and chemical characteristics.

Influence of Extruder Setup and Process Parameters on the Product Quality of Solid Polymer Electrolytes Using Melt Extrusion

All solid-state batteries (ASSBs) are the next generation battery technology, in which the classical liquid electrolyte is replaced by an ion-conducting solid electrolyte. Materials that are used as solid-state electrolytes are generally divided into three material classes: polymers, oxides and sulphides. Electrolyte materials for ASSBs have been extensively studied regarding their electrochemical performance and their stability towards the electrode materials. Nevertheless, the commercialization of ASSBs is still hindered by the material availability in case of oxide and sulphides and the knowledge of scaled production routes for all kinds of separators. Polymers are readily available on the global market. It is thus possible to focus more on the processing routes of polymer based solid electrolytes. The use of thermoplastics as matrix for solid electrolytes (SE) offers the prospect of facile upscaling of the process from lab-scale to industrial series production by the implementation of a solvent-free thermal extrusion process. A twin-screw extruder offers the possibility of continuously mixing the SE components to produce homogeneous polymer based SEs. With two feeding units, the addition of the components takes place separately. This eliminates the time-consuming premixing step to obtain a homogeneous mixture.Thermoplastic poly(ethylene oxide) (PEO) is one of the most investigated materials for polymer based SEs due to its capability to dissolve alkali salts like Lithium(bistrifluoromethanesulfonyl)imide (LiTFSI). The thermal process route of PEO and its effect on the polymeric properties are currently under investigation. Previous works from our research group show that the processability of PEO not only depends on the conductive salt (LiTFSI), but also on its molecular weight and applied process parameters. [1] With increasing molecular weight, PEO becomes more sensitive towards thermal and mechanical load that leads to chain scissoring and degradation even at small load. Hence, the use of low molecular weight PEO (Mw= 100.000 g mol-1) is preferable for the dry production of PEO based SEs.The aim of this work is to optimize the extrusion process using a co-rotating twin-screw extruder for the solvent free production of solid PEO/LiTFSI-electrolytes in a molar ratio of 20:1 (EO:Li). Here, we investigate the effects of several extruder set-ups on the mixing behaviour of PEO and LiTFSI. Therefore, type of dosing and screw design are varied. The screw can be designed with conveying, kneading and mixing elements. We compare the dry extrusion of a premixed PEO/LiTFSI (20:1) batch with dry extrusion of PEO/LiTFSI (20:1) using two feeding units, one for each component. Process parameters, such as pressure at the extruder die, actual screw speed, torque and barrel temperature are continuously measured during the production. Process temperature and screw speed are optimized to avoid degradation of PEO. PEO/LiTFSI-electrolytes are produced with a process temperature of 90 °C across the whole extruder barrel and with screw speeds of 5 – 15 rpm. The products are evaluated by their homogeneity and quality of the extruded electrolytes. Optical microscopy is used for macroscopic evaluation and the Li-salt distribution is checked with SEM/EDX. Conductivity and rheology measurements are performed to determine the lithium concentration within the electrolyte and loss of molecular weight, respectively. For the determination of the ionic conductivity, we examine electrochemical impedance spectroscopy (EIS). The characterization of the extruded electrolytes helps to find optimal process parameters for the production of polymer based SEs.

Preparation and characterization of woven jute fabric layered composite by using bamboo fiber reinforced polymers as resin matrix

In the present study, a novel hybrid composite product has been prepared by using plain woven jute fabric as one component and short bamboo fiber reinforced thermoplastic (BPC) as the second component. BPC was prepared using a co-rotating twin screw extruder and the same was used as a resin matrix for preparing hybrid jute fabric composite (JFC) via layering method. In this work, the effect of polymer type i.e., polypropylene (PP) and high-density polyethylene (HDPE), coupling agent (CA) and bamboo fiber content (10%, 30%, and 50%) in the BPC on physical, mechanical, water absorption and thermal properties of JFC has been investigated. The properties of BPC bonded JFC were compared with similarly produced composites using neat polymers. Mechanical properties and water absorption behavior in BPC bonded JFC were significantly improved with increased proportion of bamboo fibers in BPC, more specifically up to 30% fiber reinforcement. Also, the properties in fabricated composite were significantly higher in samples added with CA. Experimental results showed that flexural strength in 3L/JFC prepared with 30%-BPC was increased by 35% and 50%, as compared to similarly produced composite from neat PP and HDPE, respectively. Similarly, compared to neat PP and HDPE based JFC, the flexural modulus of 3L/JFC prepared with 30%-BPC was increased by 79% and 120%, respectively. Scanning electron microscopic images showed the evidence of physical bonding between BPC matrix and jute fabric in the form of mechanical interlocking. In general, the properties of BPC bonded hybrid JFC were significantly higher than those of similar composites made from pure polymers.

Simulation of Multiphase Flow and Mixing in a Conveying Element of a Co-Rotating Twin-Screw Extruder by Using SPH

Multiphase flows and mixing in partially filled conveying elements of twin-screw extruders (TSEs) were simulated by using smoothed-particle hydrodynamics (SPH). A validation of SPH using experiment from the literature for a co-rotating twin-cam mixer indicated good agreement. A two-phase Poiseuille flow was also used to validate the accuracy of our approach. The results of two-phase flow in TSE show that the viscosity ratio significantly affects the flow and mixing of two-phase fluids. The symmetry of flow field is broken with different parameters. In the full filled case, the pressure squeezes particles into the gap, which is conducive to improve the performance of mixing of fluids. On the contrary, in the partially filled case, because there is no background pressure, particles tend to bypass the gap and flow to the cavity of the chamber. This work laid a foundation for further study of polymer blending by simulation.

Spray Drying Enzyme-Treated Cellulose Nanofibrils.

Enzyme-treated cellulose nanofibrils (CNFs) were produced via a lab-scale mass colloider using bleached kraft pulp (BKP) to evaluate their processability and power requirements during refining and spray-drying operations. To evaluate the energy efficiency in the CNF refining process, the net energy consumption, degree of polymerization (DP), and viscosity were determined. Less energy was consumed to attain a given fines level by using the endoglucanase enzymes. The DP and viscosity were also decreased using the enzymes. The morphological properties of the enzyme-pretreated spray-dried CNF powders (SDCNFs) were measured. Subsequently, the enzyme-pretreated SDCNFs were added to a PP matrix with MAPP as a coupling agent. The mixture was then compounded through a co-rotating twin-screw extruder to determine whether the enzyme treatment of the CNFs affects the mechanical properties of the composites. Compared to earlier studies on enhancing PMCs with SDCNF powders, this research investigates the use of enzyme-pretreated SDCNF powders. It was confirmed that the strength properties of PP increased by adding SDCNFs, and the strength properties were maintained after adding enzyme-pretreated SDCNFs.

Thermo-mechanical and morphological studies of Hal-reinforced PEEK

This study is focused on exploring the thermo-mechanical properties and behaviour of PEEK-Hal nanocomposites as a case study for understanding the interactions between nanoparticles and polymers, as well as to explore potential applications of nanocomposites in the field of engineering. The selection of Poly (ether ether ketone) (PEEK) polymer is based on its notable chemical resistance, exceptional mechanical properties and high thermo-oxidative stability. Halloysite nanotubes (Hal) are chosen for their environmentally friendly nature, non-toxic properties, cost-effectiveness, tuneable release and rapid adsorption rates. This research paper focuses on the fabrication of PEEK-Hal polymer composites with varying concentrations using a co-rotating twin screw extruder. The prepared composites are thoroughly characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The mechanical properties are assessed using a universal testing machine (UTM), impact tester, and hardness tester, respectively. The surface morphology is examined using field emission scanning electron microscopy (FE-SEM) technique. The results highlight the substantial benefits of incorporating Hal, improving interfacial adhesion, and establishing favourable interactions between the PEEK and Hal. The incorporation of Hal notably enhances the stiffness and storage modulus of the PEEK-Hal composites. Additionally, the presence of Hal restrains the mobility of the macromolecular chains within the composite. This study demonstrates that the PEEK-Hal composite with a 3% concentration of Hal (PH3) exhibits remarkable thermo-mechanical properties.

Investigation of the effect of materials and processing conditions in twin-screw extrusion

Three polymeric materials; polystyrene (amorphous), low-density polyethylene (semi-crystalline), and poly(methyl methacrylate) (amorphous) were used to explore their behavior and properties during processing using a co-rotating twin-screw extruder. Injection molding and compression molding were used for preparing the test specimens. Screw speed and barrel set temperatures were considered as the main processing variables while observing the process energy consumption of the extruder. The tensile, thermal, and rheological properties of the extruded materials under different processing conditions were evaluated. Test results confirmed that the motor power of the extruder for processing polystyrene and low-density polyethylene increased with increasing screw speed and decreased with increasing barrel set temperatures. Motor power for processing poly(methyl methacrylate) increased significantly with increasing screw speed. The total power consumption of the barrel heaters for processing polystyrene and low-density polyethylene slightly increased with the barrel set temperatures. The tensile modulus of polystyrene decreased with increasing screw speed at higher barrel set temperatures, while low-density polyethylene showed no significant variation. The tensile modulus of poly(methyl methacrylate) did not exhibit a clear trend with the extruder process settings. The effect of process settings on the glass transition temperature and melting temperature of the polymers was not significant, and no evidence was found of any molecular degradation during processing. Rheological properties of poly(methyl methacrylate) showed a significant variation with increasing screw speed and barrel set temperatures, while those of polystyrene and low-density polyethylene did not exhibit a consistent variation.

Optimization of Machine and Process Parameters for Development of Protein and Antioxidant Rich Composite Food using Twin Screw Extruder

Background: Nutritional quality of extruded products can be enhanced through protein, minerals and antioxidants rich foods viz. legumes, green leafy vegetables, dietary fibres, by-products, etc, leading to improvement in functional properties of products and health of consumers. Methods: Extrudates were prepared from maize, defatted soy meal, sesame and spinach using a co-rotating twin screw extruder and dried in a tray dryer at 50oC up to about 5.5% moisture content (w.b.) and analyzed for important product quality parameters. Result: Quality characteristics of developed food grains-spinach based composite food were affected by variability in independent studied parameters. Optimized extrusion conditions for desired composite food from food grains-spinach were as 14% moisture content, 117oC DHT and 335rpm screw speed. These conditions resulted in the products with 18.26% protein, 73.88% in vitro protein digestibility, 2.46 protein efficiency ratio, 2.84% total minerals, 4.67mg/100g iron, 190 mg/100g calcium, 24.05% antioxidant activity with consumer acceptability ≥7 by 92.52%.