Extrusion Technology Research Articles

"Fabrication of cutting inserts with chromium-molybdenum steel for turning operations using material extrusion technology"

In this study, cutting inserts for turning were produced using metal 3D printing's material extrusion technology. The primary focus was on optimizing cutting parameters. An experimental plan was devised involving rounds of cutting tests based on a design of experiments and analysis of variance. Inserts were manufactured by printing bound metal powder filament, a combination of chromium-molybdenum tool steel with a polymeric binder. After printing, green parts underwent debinding to eliminate the binder, eventually resulting in full metal parts via sintering. These inserts underwent machining tests on aluminum-copper EN AW-2030 alloy specimens. Results indicated that the inserts could function within cutting speeds (Vc) ranging from 40 to 260 m/min, feed rates (f) from 0.05 to 0.25 mm/r, and radial pass depths (ap) from 0.1 to 2.4 mm. Optimal technological conditions were determined as Vc = 160–200 m/min, f = 0.20–0.25 mm/r, and ap = 1.2 mm. Analysis revealed that cutting speed was less significant than feed rate or depth of cut on tool wear. Feed rate minimized wear within the 0.15–0.25 mm/r range, while pass depth proved most influential on wear, with optimal values between 0.8 and 1.2 mm. Surface finish, assessed through mean roughness Ra, showed high dependence on pass depth, improving for low ap values and relatively high Vc values. These findings demonstrate that inserts fabricated via material extrusion can operate within a technological range like commercial inserts, presenting an advanced approach for customizing design and manufacturing while surpassing conventional insert limitations.

Multimaterial extrusion of programmable periodic filament structures via modularly designed extruder heads

There is a growing interest in patterning multimaterial structures into one-dimensional, two-dimensional, and three-dimensional motifs with spatially programmable inner structures. Harnessing material extrusion technology with customizable extruder heads greatly expands the possibilities of 3D printing to generate diverse multimaterial structures. However, the current choices of extruder heads are still limited largely due to the complexity in the design and fabrication of high-resolution microfluidic channels for multimaterial ink extrusion. Here, we report a modular strategy in multimaterial extrusion to program periodic structures and material compositions in printed objects. Our modular design greatly simplifies the design and manufacturing of multimaterial extruder heads to rapidly print complex multilayered architectures. Moreover, different extruder head modules can be combined in series or in parallel and different filament morphologies can be controlled by adjusting printing parameters such as flow rate and pressure. As exemplars, two immiscible materials with similar rheological properties but different mechanical properties are used for co-extrusion. The lamellar composite filaments and printed woodpile structures exhibit high toughness and superior energy-absorption capability, respectively. Our strategy provides new insights for the design of innovative filament structures for 3D printing and shows broad application prospects in tissue engineering, structural systems, optoelectronics, and beyond.

Hot Melt Extrusion Technology as a Modern Strategy for Improving the Bioavailability of Flavonoids

Hot Melt Extrusion Technology as a Modern Strategy for Improving the Bioavailability of Flavonoids

High-quality acrylic fibers from waste textiles

The objective of this work is to develop a closed-loop recycling method specifically tailored for acrylic fibers. Recycling waste acrylic is essential, given the vast volumes of acrylic-containing textiles produced yearly and the strong capability of acrylics to generate toxic microplastics. However, none of the available closed-loop recycling, mechanical recycling, chemical recycling, and direct extrusion technologies work for acrylics. Acrylic fibers are always blended with other textile fibers, making fiber separation via mechanical recycling almost impossible. Polyacrylonitrile, an addition-polymerized thermoplastic material, cannot be depolymerized into its original monomer. Direct extrusion of waste acrylics faces issues of uncontrollable colors on fibers and pollution of spinning lines due to the influence of existing colorants. In our method, acrylic fibers were extracted from waste textiles using a novel approach involving maximized acrylic swelling and dissolution with dimethyl sulfoxide and butanediol. Cationic dyes were effectively removed through cost-effective recycling technology. This work demonstrates that cationic dyes seriously affect the acrylic dissolution, color consistency, and dyeability of regenerated fibers via direct wet extrusion. Such negative impacts of dyes have been eliminated by our cost-effective and closed-loop acrylic recycling technology, which enables the efficient separation of non-acrylic fibers and dyes from acrylic fibers. Our recycling system achieved zero discharges through recycling solvents, dyes, and acrylics. The regenerated acrylic fibers exhibited mechanical properties and dyeability comparable to virgin acrylic fibers. The material and energy costs to produce pure acrylic from waste textiles were only 40 % of those from fossils. This study successfully introduces a closed-loop recycling method for acrylic fibers from waste textiles, addressing key challenges in acrylic fiber recycling. Further research and implementation of this technology are recommended to advance its commercial viability and widespread adoption.

Application of resource-saving extrusion technologies and an integrated approach to assessing the plasticity of metal parts in agricultural engineering

Application of resource-saving extrusion technologies and an integrated approach to assessing the plasticity of metal parts in agricultural engineering

Preparation and physicochemical properties: a new extruded rice using cassava starch and broken rice flour

With the increasing demand for nutrition and health, many researchers are trying to develop a rice product with lower aging rate and convenient nutrient fortification. Being composed of high amylopectin content, cassava starch (CS) shows a lower retrogradation tendency compared to rice starch. So, it has a broad application prospect to partially replace rice starch with CS in rice by extrusion technology. In this study, a new extruded rice (ER) was prepared by broken rice flour and CS using single-screw extruder through “improved extrusion cooking technology,” and the maximum addition level of CS in ER was 30%. Color parameters and texture profile analysis showed that ER was a little darker in appearance with lower hardness, adhesiveness and chewiness. Rapid visco analysis demonstrated that the viscosity of ER paste appeared earlier during the initial heating phase and displayed a lower retrogradation trend than normal rice in the cooling process. The gelatinization temperature and gelatinization enthalpy decreased with the increasing CS in ER, while the degree of gelatinization increased to 76.36% when the content of CS was 30% after extrusion. The X-ray diffraction patterns of control was typical A-type structure, while ER changed to V-type structure with a lower degree of crystallinity. The microstructure observation showed that ER exhibited a looser and more porous structure with increasing the content of CS, which facilitated easier cooking and nutritional enhancement.

HME-assisted formulation of taste-masked dispersible tablets of cefpodoxime proxetil and roxithromycin

ObjectivesAntibiotics are the most commonly administered medications among pediatric patients. However most of the time, accurate dose administration to children becomes a problem due to the extremely bitter taste. Cefpodoxime proxetil (CP) and roxithromycin (ROX) are antibiotics often prescribed to the pediatric population and have a bitter taste. Marketed formulations of these drugs are dry suspension and/or tablets. The lyophilization method involves various steps and thus is time consuming and expensive. The objective of this study was to mask the bitter taste of CP and ROX without compromising the solubility and drug release profile compared to marketed formulations, as well as to overcome the disadvantages associated with the currently used lyophilization technique. MethodsHot melt extrusion (HME) technology was used to process CP and ROX individually with Eudragit E PO polymer. The extrudates obtained were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry. The powdered extrudates were formulated as dispersible tablets and evaluated for in vitro and in vivo taste-masking efficiency. ResultsThe tablets prepared in this study showed comparable dissolution profiles but the taste-masking efficiency was significantly enhanced compared to the marketed tablets of CP and ROX. The results of in vivo human taste-masking evaluation were also in agreement with the in vitro taste-masking studies. ConclusionThe current work presents solvent-free, scalable, and continuous HME technology for addressing the bitter taste issues of CP and ROX. The disadvantages associated with the currently used lyophilization technique were overcome by developing the formulations using HME technology.

3d printing of thermoplastic elastomers with electrical conductivity

On April 03, 2024, Kraiburg TPE published this blogpost from Johanna Schmid, Market Manager Industry at Kraiburg TPE, discussing the challenges and advancements in using thermoplastic elastomers (TPE) in 3D printing with electrically conductive materials. In her blogpost, she also highlights the limitations of traditional 3D printing processes with TPE materials due to issues like conversion difficulties and uniform extrusion. She outlines the solution of using pellet extrusion technology for TPE, emphasizing its versatility, cost-effectiveness, and suitability for functional prototyping and serial production. Additionally, she underscores the growing demand for electrically conductive materials in various applications.

Single and repeated impact behavior of material extrusion-based additive manufactured PLA parts

The advent of Additive Manufacturing (AM) for producing components or parts made of thermoplastic polymers have increased the necessity of a deep knowledge of their mechanical properties. In particular, the mechanical performance under impact loads is still not fully investigated and requires a thorough knowledge. In this paper, polylactic acid (PLA) samples were produced by material extrusion (MEX) technology and subjected to low velocity impact (LVI) tests by using different impactors’ geometries and impact energies. Initially, the PLA filament and MEX-printed samples were subjected to a physico-chemical evaluation through TG, DSC and FTIR analyses. The FTIR and DSC analyzes highlighted phase transitions specific to semicrystalline PLA polymer, while the TG analysis showed that the used printing temperature (220 °C) does not affect the thermal behavior of the filament. The mechanical assessment consisted of single and repeated LVI tests on the same sample until total penetration or failure were reached. The samples subjected to impact tests were analyzed by digital radiography to detect the internal damage and failure mechanisms. The impactor shape has a strong effect on the mechanical strength of the tested samples. For single impacts, the peak load was higher for the 20 mm diameter hemispherical impactor (H20), while the lowest value was experienced by the samples tested with 10 mm diameter hemispherical impactor (H10). The lowest value of specific absorbed energy was recorded with the truncated conical (TC) impactor. For multiple impacts, with the H10 and TC impactors it was possible to impact the sample 4 times, respectively; 2 times with the H20 impactor.

Investigation on low hydrostatic stress extrusion technology for forming of large thin-walled components with high ribs

An increase in hydrostatic stress improves the plasticity of metallic materials. However, for some special components, such as large thin-walled components with high ribs, excessive hydrostatic stress can cause several problems that make it impossible to prepare such components using plastic forming methods. In this study, the effect of hydrostatic stress on the deformation behavior of large thin-walled components with high ribs was investigated using a combination of numerical simulations and theoretical derivations. The results indicated that excessive hydrostatic stress leads to die failure, causing metal flow difficulties, uneven deformation, inconsistent mechanical properties, and reduced forming accuracy. Therefore, a low-hydrostatic-stress extrusion method was proposed by adjusting the contact friction, metal flow direction and displacement, and force boundary conditions to reduce the hydrostatic compressive stress. These principles are mainly reflected in the following three aspects: First, the size of the difficult deformation zone was reduced by changing the friction conditions from dry friction to fluid friction or boundary friction to reduce the frictional resistance. Second, the high-stress zone was eliminated by changing the metal flow direction, adjusting the strain state from unidirectional to multi-directional flow, shortening the metal flow path, and reducing the metal flow resistance. Third, the strong compressive stress state in the three directions was weakened by regulating the force boundary conditions and changing the loading method from one-way extrusion to multi-directional loading. Based on these principles, a series of new forming technologies have been developed, such as actively counteracting frictional resistance, slotting, and ditching on dies for long-lasting lubrication, multi-directional short-range metal flow, drawing-assisted extrusion, and multi-directional active loading. The adoption of these technologies realizes the labor-efficient formation of large thin-walled components with high ribs and provides the formed members with high precision and uniform mechanical properties.

Formulation and evaluation of inhaled Sildenafil-loaded PLGA microparticles for treatment of pulmonary arterial hypertension (PAH): A novel high drug loaded formulation and scalable process via hot melt extrusion technology (Part Ⅰ)

In recent years, several techniques were employed to develop a local sustained pulmonary delivery of sildenafil citrate (SC) as an alternative for the intravenous and oral treatment of pulmonary arterial hypertension (PAH). Most of these methods, however, need to be improved due to limitations of scalability, low yield production, low drug loading, and stability issues. In this study, we report the use of hot-melt extrusion (HME) as a scalable process for making Poly (lactic-co-glycolic acid) (PLGA) microparticles with high SC load. The prepared particles were tested in vitro for local drug delivery to the lungs by inhalation. Sodium bicarbonate was included as a porogen in the formulation to make the particles more brittle and to impart favorable aerodynamic properties. Six formulations were prepared with different formulation compositions. Laser diffraction analysis was used to estimate the geometric particle size distribution of the microparticles. In-vitro aerodynamic performance was evaluated by the next-generation cascade impactor (NGI). It was reported in terms of an emitted dose (ED), an emitted fraction (EF%), a respirable fraction (RF%), a fine particle fraction (FPF%), a mass median aerodynamic diameter (MMAD), and geometric standard deviation (GSD). The formulations have also been characterized for surface morphology, entrapment efficiency, drug load, and in-vitro drug release. The results demonstrated that PLGA microparticles have a mean geometric particle size between 6 and 14 µm, entrapment efficiency of 77 to 89 %, and SC load between 17 and 33 % w/w. Fifteen percent of entrapped sildenafil was released over 24 h from the PLGA microparticles, and seventy percent over 7 days. The aerodynamic properties included fine particle fraction ranging between 19 and 33 % and an average mass median aerodynamic diameter of 6–13 µm.

Comparative analysis of flow factors and crystallinity in conventional extrusion and gas-assisted extrusion

Abstract Two-dimensional models of die-melt and die-gas-melt were created using Polyflow software. The radial and axial directions flow rate, shear rate, pressure, and first normal stress of the specimen were numerically simulated under conventional extrusion and gas-assisted extrusion while taking into consideration the heat transfer on the free surface of the specimen. The crystallinity was determined by combining the simulation data with the crystallization kinetics equation. The computation results are then examined using Origin software. The findings demonstrate that the use of gas-assisted extrusion technology can cause the Vx to decrease or even turn negative by reducing the friction between the melting edge and the die wall. Additionally, it makes Vy , pressure, shear rate, temperature, first normal stress, and crystallinity increasingly steady and aids in reducing or avoiding the Barus effect. The crystallization phenomena can be measured by using the crystallization kinetics equation. The study of extruded parts at the microscopic level will benefit from this application.

Exploring the relationship between starch structure and physicochemical properties: The impact of extrusion on highland barley flour

Highland barley (HB) is an intriguing plateau cereal crop with high nutrition and health benefits. However, abundant dietary fiber and deficient gluten pose challenges to the processing and taste of whole HB products. Extrusion technology has been proved to be effective in overcoming these hurdles, but the association between the structure and physicochemical properties during extrusion remains inadequately unexplored. Therefore, this study aims to comprehensively understand the impact of extrusion conditions on the physicochemical properties of HB flour (HBF) and the multi-scale structure of starch. Results indicated that the nutritional value of HBF were significantly increased (soluble dietary fiber and β-glucan increased by 24.05%, 19.85% respectively) after extrusion. Typical underlying mechanisms based on starch structure were established. High temperature facilitated starch gelatinization, resulting in double helices unwinding, amylose leaching, and starch-lipid complexes forming. These alterations enhanced the water absorption capacity, cold thickening ability, and peak viscosity of HBF. More V-type complexes impeded amylose rearrangement, thus enhancing resistance to retrogradation and thermal stability. Extrusion at high temperature and moisture exhibited similarities to hydrothermal treatment, partly promoting amylose rearrangement and enhancing HBF peak viscosity. Conversely, under low temperature and high moisture, well-swelled starch granules were easily broken into shorter branch-chains by higher shear force, which enhanced the instant solubility and retrogradation resistance of HBF as well as reduced its pasting viscosity and the capacity to form gel networks. Importantly, starch degradation products during this condition were experimentally confirmed from various aspects. This study provided some reference for profiting from extrusion for further development of HB functional food and “clean label” food additives.

Preparation of tofacitinib sustained-release tablets using hot melt extrusion technology

This study aimed to develop a tablet that shows a drug release profile similar to the tofacitinib sustained-release tablet (Xeljanz XR®; OROS™) using hot melt extrusion technology. Tofacitinib citrate was selected as the drug. HPMCAS, HPMCP, and Kollidon VA64 were used as thermoplastic polymers to prepare a hot-melt extrudate. The extrudate was obtained from a twin screw extruder and pelletizer. The granules were compressed using a single punch press machine and then coated. TGA, DSC, XRD, FT-IR, and SEM were performed on the hot melt extrudate to understand its physicochemical properties. Dissolution tests were performed using the paddle method (USP Apparatus II). The results showed that the crystallinity state of tofacitinib changed to amorphous after the hot melt extrusion process; however, no chemical change was observed. The drug release profile was similar to that of Xeljanz XR®, which has an initial lag time owing to its OROS™ formulation; a coating process was performed to obtain a similar drug release profile. The lag time was controlled by adjusting the thickness of the coating layer. Moreover, the extrudate size and compression force during tableting did not significantly affect drug release. In conclusion, the new tofacitinib sustained-release tablet prepared using hot melt extrusion showed a drug release behavior similar to that of Xeljanz XR®.

Effects of Extrusion Technology on Physicochemical Properties and Microstructure of Rice Starch Added with Soy Protein Isolate and Whey Protein Isolate.

In order to improve the retrogradation of rice starch (RS) and the quality of rice products, soy protein isolate (SPI), whey protein isolate (WPI), and rice flour were mixed and further extruded into mixed flour. The physicochemical properties and morphology of starch of extruded rice flour (ERS) and starch of extruded mixtures of SPI, WPI, and rice flour (SPI-WPI-ERS) were analyzed. The distribution of amylopectin chain length, molecular weight, microstructure, crystallinity, short-range ordered structure, pasting properties, and thermodynamic properties of RS, ERS, and SPI-WPI-ERS were measured. The results showed that, compared with rice starch, the proportion of long-chain starch, total starch content, and molecular weight were decreased in ERS and SPI-WPI-ERS, but the proportion of short-chain and amylose content was increased. The short-range order structure was destroyed. The water absorption of ERS and SPI-WPI-ERS was much higher than rice starch at 55 °C, 65 °C, and 75 °C, but lower than that of rice starch at 95 °C. Therefore, the retrogradation characteristics of SPI-WPI-ERS were improved. The setback of rice starch products was reduced and the setback of SPI-WPI-ERS was lower than that of ERS. Overall, the retrogradation of rice starch was delayed by adding exogenous protein and extrusion technology, and the application range of rice flour in staple food products was broadened.

Additive manufacturing of self-sensing parts through material extrusion

ABSTRACT The objective of this study is to develop and evaluate self-sensing capabilities in additively manufactured parts by embedding conductive elements that are copper and continuous carbon fiber. Two sets of test specimen were manufactured using a custom g-code on material extrusion-based Anisoprint A4 machine. Each set contained copper and continuous carbon fiber in an amorphous thermoplastic matrix. A tailor-made test setup was developed by improvising the American Society for Testing and Materials (ASTM D790) three-point loading system. Electrical resistance measurements were conducted under flexural loads to evaluate the self-sensing capability of each test specimen. The results confirmed that material extrusion technology can allow production of self-sensing parts. The electrical resistance increases linearly (Sensing tolerance <±2.6%, R2>93.8% p-value < 0.005), establishing a strong correlation with applied force and strain. The work allows for creating smart parts that can facilitate big data collection, analysis, and evidence-based decision-making for condition monitoring and preventive maintenance needed for Industry 4.0.

Formulation Development of Solid Self-Nanoemulsifying Drug Delivery Systems of Quetiapine Fumarate via Hot-Melt Extrusion Technology: Optimization Using Central Composite Design.

Quetiapine fumarate (QTF) was approved for the treatment of schizophrenia and acute manic episodes. QTF can also be used as an adjunctive treatment for major depressive disorders. QTF oral bioavailability is limited due to its poor aqueous solubility and pre-systemic metabolism. The objective of the current investigation was the formulation development and manufacturing of solid self-nanoemulsifying drug delivery system (S-SNEDDS) formulation through a single-step continuous hot-melt extrusion (HME) process to address these drawbacks. In this study, Capmul® MCM, Gelucire® 48/16, and propylene glycol were selected as oil, surfactant, and co-surfactant, respectively, for the preparation of S-SNEDDS. Soluplus® and Klucel™ EF (1:1) were selected as the solid carrier. Response surface methodology in the form of central composite design (CCD) was utilized in the current experimental design to develop the S-SNEDDS formulations via a continuous HME technology. The developed formulations were evaluated for self-emulsifying properties, particle size distribution, thermal behavior, crystallinity, morphology, physicochemical incompatibility, accelerated stability, and in vitro drug release studies. The globule size and emulsification time of the optimized SNEDDS formulation was 92.27 ± 3.4 nm and 3.4 ± 3.38 min. The differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) studies revealed the amorphous nature of the drug within the formulation. There were no drug-excipient incompatibilities observed following the Fourier transform infrared (FTIR) spectroscopy. The optimized formulation showed an extended-release profile for 24 h. The optimized formulation was stable for three months (last time-point tested) at 40 °C/75% RH. Therefore, the developed S-SNEDDS formulation could be an effective oral delivery platform for QTF and could lead to better therapeutic outcomes.

Water binding ability changes of different proteins during high-moisture extrusion

High-moisture extrusion technology (40% ∼ 80% moisture content) has shown the advantages for producing plant-based meat products with rich meat-like fibrous structures; however, it faces the issue of insufficient juiciness. Juiciness is associated with water characteristics such as water holding capacity and water distribution, and the variations in water binding ability of proteins during high-moisture extrusion may offer valuable insights into this perspective. Thus, the water binding ability changes of plant proteins from five common sources during high-moisture extrusion were investigated in this study. Results showed the extrudates of soy protein isolate (SPI), soy protein concentrate (SPC) and wheat gluten (WG) exhibited fibrous structures at a centimeter level, respectively, and the microscopic morphology of SPI extrudates was more uniform. SPI showed the strongest water holding capacity and highest gel strength, leading to a faster binding rate with water compared to other proteins during the heating process. Moreover, the lowest water activity, freezable water content, T21 and T22 were found after extrusion of SPI, indicating that it was the most tightly bound to water. While, rice protein isolate (RPI) failed to extrude into a regular shape, and its extrudates showed the lowest density with a poor water binding ability. It was also found that the water activity of the extrudates was related to the solubility of the protein raw materials, and proteins with high solubility (PPP) showed lower water activity after extrusion. The results confirmed that the water binding ability of proteins could affect the water content, water state and distribution in the extrudates. These findings provided evidence for exploring the juiciness of plant-based meat products from the perspective of protein-water interaction.

Application of 3D printing technology for the development of dose adjustable geriatric and pediatric formulation of celecoxib

Developing safe and effective formulations for the geriatric and pediatric population is a challenging task due to issues of swallowability and palatability. The lack of standardized procedures for pediatric formulations further complicates the process. Manipulating adult formulations for children can lead to suboptimal efficacy and safety concerns. To overcome these challenges, minitablets or spinklets are preferred for the geriatric and pediatric population due to their smaller size and flexible dose adjustment. The aim of this study is the development of a 3D printed spinklets formulation of celecoxib, a nonsteroidal anti-inflammatory drug, using hot melt extrusion to address the limitations of traditional manufacturing methods. Three different formulations of celecoxib were prepared using Poly-2-ethyl-tetra-oxazoline (Aquazol) with and without surfactant. Subsequently, the mechanical properties and solubility of the drug-loaded filaments were evaluated. Solid state characterization confirmed the drug conversion into an amorphous form during the extrusion process, Computer-aided design software facilitate sprinklets design for fused deposition modeling and scanning electron microscopy assess the surface morphology. Sophorolipids plasticize better than TPGS, resulting in lowering processing temperatures during melt extrusion. In vitro drug release showed successful enhancements in the dissolution of oral medications for pediatric patients, considering their distinctive physiological characteristics. Overall, this study demonstrates the successful development of PEtOx-based 3D printed celecoxib sprinklets by coupling hot-melt extrusion and 3D printing technology. Future exploration holds the potential to revolutionize pharmaceutical production and advance personalized medication formulations.

Extrusion inhibits lipolytic enzymes in pearl millet (Pennisetum glaucum) flour

The present study was undertaken to evaluate the effect of extrusion technology on anti-nutritional factors and lipolytic enzymes in pearl millet. The effect of process parameters such as die temperature (140–160 °C), screw speed (150–190 rpm), and feed moisture content (24–30%) was evaluated using response surface methodology. The extrudates so obtained were evaluated for their physico-chemical and functional properties. Optimized extrudate that showed maximum inhibition of anti-nutritional factors and lipolytic enzymes was evaluated for extent of starch gelatinization by differential scanning calorimetry, structural properties by FTIR, morphology by scanning electron microscopy, and crystallinity by X-ray diffractometry. Extrusion at 140 °C/150 rpm/30% moisture content could decrease trypsin inhibitors (∼100%), phytic acid (up to 89%) and condensed tannin (up to 85%), and inhibited lipase and lipoxygenase activities by 79.2 and 77.9%, respectively. The results so obtained are promising for extending the shelf life of pearl millet flour and utilizing it in food premixes. Industrial relevance textThe presence of lipase and lipoxygenase enzymes in pearl millet limits its shelf life due to generation of free fatty acids which results in bitter taste and off flavour. The presence of anti-nutrients such as phytic acid, trypsin inhibitor and condensed tannins restricts its digestibility, and poses challenges to its commercial as well as domestic use. Extrusion has attracted attention in millet processing due to its feasibility for implementation in the food industry without major additional costs. The extrusion processing parameters, mainly temperature, screw speed and moisture content 140 °C/150 rpm/30% decreased trypsin inhibitors (∼100%), phytic acid (up to 89%) and condensed tannin (up to 85%), and inhibited lipase and lipoxygenase activities by 79.2 and 77.9%, respectively. These results on inhibition of lipolytic enzymes through extrusion could help in extending the shelf life of pearl millet flour. It is anticipated that extruded pearl millet flour could form a base for premixes based thereon.