Optimum Extrusion Conditions Research Articles

Optimization of germinated cowpea flour ratios and extrusion conditions on the nutritional composition and sensory quality of Ethiopian emmer wheat-based extruded porridge

Childhood malnutrition is a major problem in developing countries, particularly in Ethiopia. This study aimed to create nutritious emmer wheat and cowpea extruded porridge with optimal macronutrient levels and sensory quality. Utilizing Design-Expert software, the effects of cowpea blending ratios (10–25 %), barrel temperatures (80–120 °C), and feed moisture content (22–26 %) were analyzed using a three-factor, three-level Box-Behnken design. Significant impacts on nutritional characteristics were observed, leading to the identification of optimal extrusion conditions (cowpea blend: 20.17 %, moisture content: 25.91 %, barrel temperature: 117.20 °C). Blending emmer wheat with cowpea flour significantly enhanced the porridge's color, taste, and aroma. The highest color intensity (4.36 %) was at 10 % cowpea and 22 % moisture processed at 100 °C. The best taste (4.41 %) was with 25 % cowpea and 22 % moisture at 100 °C, while the highest aroma was in blends with 10 % and 25 % cowpea at 100 °C. The control had the best mouthfeel (4.36 %), but a blend with 25 % cowpea, 24 % moisture, and 80 °C barrel temperature had the highest overall acceptability (4.31 %). The study highlighted the potential of these protein-rich porridge products to address protein-energy malnutrition, particularly in Ethiopia, by introducing awareness about the unique nutritional composition of Ethiopian emmer wheat and underutilized cowpea, thus creating a new market for nutritious food options.

Wear resistance of extruder parts in the production of polymer nanomodified products

Extrusion equipment is widely used in the production of polymer materials. One of the urgent questions that arises when studying the processes of obtaining polymer products by the extrusion method is the question of studying abrasive wear, which may depend on the efficiency of the equipment, the duration and reliability of its work. In the context of abrasive wear, the process that needs attention is the extrusion of polymer materials with carbon nanotubes. The purpose of this work is to develop a numerical method for determining the evolution of abrasive wear of the equipment of the extruder working area in the process of processing nanomodified polymer granules and determining the life cycle of this equipment with in order to increase the parameters of their durability. The specific objectives of the study include: 1) Determination of the influence of the content of CNTs in PVC on the rate of wear of the steel surface of the extruder; 2) Analysis of the dependence between friction and the content of CNTs in the polymer composite; 3) Establishing optimal extrusion conditions to minimize abrasive wear of the steel surface; 4) Comparison of simulation results with experimental data to check the reliability of the model. The work is aimed at understanding the processes that occur during the extrusion of nanocomposites and their impact on the wear resistance of equipment materials, which can contribute to the improvement of technological processes and ensure longer and more efficient operation of extruders in production conditions. It has been established that the processes of extrusion processing of polymer nanoreinforced composites can be effectively studied by developing and implementing numerical models that take into account the interaction of all physical and mechanical parameters of a representative volume of the contact zone of the equipment with the polymer and the nanotube with the adhesive layer. In this work, a model for determining the physical and mechanical properties of the interface layer between the CNT and the polymer array is constructed and implemented. The technique for determining the properties of the nanotube-polymer interface is integrated into the APROKS system for analyzing the stress-strain state of nanomodified polymer materials. Based on a multilayer isoparametric FE, a series of numerical experiments were carried out to simulate the process of abrasive wear of the material of equipment elements in the extruder working area. The possibility of a detailed study of the processes of nonlinear contact interaction of nanotubes with an interface layer with equipment elements of the extruder working area based on multilayer FE has been confirmed. Diagrams were obtained that determine the service life of equipment in the working area of the extruder depending on the volume concentration of carbon nanotubes in the polymer at different levels of operating pressure in the “nanotube – polymer – equipment” contact system. It is advisable to use the proposed methodology in the development of information support systems for the life cycle of operation of equipment in the working area of extruders intended for the production of nanomodified polymer products.

Manufacture of Biomimetic Auricular Surgical Implants Using 3D Printed High Density Polyethylene Microfibers

AbstractThis study demonstrates a new approach to manufacturing biomimetic auricular surgical implants using melt electrowriting (MEW) technology to fabricate microfiber high‐density polyethylene (HDPE) scaffolds. An emerging filament‐driven printhead and MEW printer, termed the “MEWron”, is used to enable precise control over the material extrusion process and fiber formation. By predicting the optimal extrusion conditions, continuous and uninterrupted fiber production is achieved, enabling further optimization of filament‐driven MEW fibers with a diameter of 60.5 ± 2.6 µm. As a case study, an application of microfiber HDPE fabrication is selected that comprised the design and fabrication of personalized auricular (ear) surgical implants, specifically tailored to match the unique morphology of individual patients. Patient‐specific implant models matched to the natural shape and structure of the human ear are successfully fabricated. Furthermore, the manufactured implants exhibit excellent mechanical properties, offering a 13‐fold increase in tensile stiffness compared to MEW PCL scaffolds. Overall, this research demonstrates the feasibility and potential of MEW‐based HDPE implants as a promising alternative to traditional auricular reconstruction methods, offering an alternative avenue for improved patient outcomes and enhanced aesthetic results.

Effects of Process Variables on the Physicochemical, Textural, and Structural Properties of an Isolated Pea Protein-Based High-Moisture Meat Analog.

This study investigated the optimal extrusion conditions required to produce an isolated pea protein (IPP)-based meat analog. High-moisture extrusion cooking (HMEC) was performed. The effects of the moisture content (55 and 60%), barrel temperature (165 and 175 °C), and screw speed (150 and 200 rpm) on the physicochemical, textural, and structural properties of the high-moisture meat analog (HMMA) were determined. The results showed that the moisture content had a significant effect (p < 0.05) on the physicochemical and textural properties of the HMMA. A lower moisture content had significant impact (p < 0.05) on enhancing the texturization of the HMMA and the formation of fibrous structures, thereby increasing the texture profile analysis (TPA) and cutting strength of the HMMA. Protein denaturation during HMEC resulted in a lower protein solubility of the meat analog than the raw material. The content of β-sheets and β-turns in the meat analogs were higher than that in the raw material, while the content of random coils and α-helices is inversely proportional. The process variables had no significant (p > 0.05) effect on the secondary structures. In conclusion, the moisture content is the most important factor affecting the properties of HMMAs. The extrusion process variables for HMMAs are a moisture content of 55%, a barrel temperature of 175 °C, and a screw speed of 200 rpm.

The effect of extrusion condition and blend proportion on the physicochemical and sensory attributes of teff-soybean composite flour gluten free extrudates

The effects of soybean-to-teff ratio (SB), feed moisture content (FM) and barrel temperature (BT) on physico-chemical properties and sensory attributes of extruded product from teff-soybean flour blend was studied. Increase in BT resulted in increase in expansion ratio(ER), water absorption index (WAI), and water solubility index (WSI) whereas the bulk density (BD) and hardness decreased with increase in BT. Increase in the proportion of SB resulted in increased BD, hardness, and reduced water solubility index (WSI) and sensory scores. Three principal components explained 89.1 % of the variations where the first (PC1), the second (PC2) and the third (PC3) principal components explained 62.4, 20.2 and 6.5 % of the variations respectively. BD, WAI and Hardness are strongly and positively associated with each other whereas they are negatively associated with WSI, crispiness, Specific length (Lsp) and ER. Graphical optimization gave best results for BT between 128 and 137 °C and SB proportion between 2 and 7.3 % where the FM is fixed at 10 %. Besides, BT of 135 °C to137 °C, FM of 10–12 % when the SB proportion is fixed at 7.5 % gave optimal product quality. The numerical optimization resulted in optimal extrusion conditions for optimal product quality were BT of 135 °C, FM of 10 % and SB proportion of 5 % with a desirability value of 0.875. The results revealed that SB can be incorporated up to 7.5 % to obtain an acceptable product. Therefore it is possible to produce gluten-free extruded snack by blending teff and soybean flour.

Tensile Properties of 3D Printed Recycled PLA Filament: A Detailed Study on Filament Fabrication Parameters

Polylactic acid (PLA), a biodegradable and biocompatible thermoplastic commonly utilized in 3D Printing filaments, undergoes changes in properties upon recycling. The objective was to elucidate the role of extrusion temperature and screw speed in modulating the quality of recycled PLA filament, as well as in controlling its dimensional attributes. Recycled PLA pellets (3D850D) were extruded using a single filament extruder machine within an extrusion temperature range of 145°C to 165°C and a screw speed varying from 2 rpm to 6 rpm. The extruded filaments were subsequently 3D printed into specimens adopting a 0° raster angle, line infill pattern, and a 100 percent infill density, then tested as per ASTM D638 mechanical standards. The study revealed a profound influence of extrusion parameters on the filament's ultimate tensile strength, yield strength, and diameter. Optimal extrusion conditions - 155°C and 5 rpm - resulted in maximum mechanical strengths, while the parameters yielding filament diameters closest to commercial standards were identified as 5 rpm and 155°C. These results under-score the possibility of optimizing the recycled PLA filament's properties through adept control of extrusion parameters. Consequently, this investigation supports the potential use of recycled PLA filament in the 3D printing industry as a sustainable and performance-efficient material, offering a tangible step towards environmentally friendly additive manufacturing practices.

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%.

Dry sliding wear behavior of additively manufactured cenosphere-filled PETG syntactic foam composites

PurposeThis study aims to deal with developing composite filaments and investigating the tribological behavior of additively manufactured syntactic foam composites. The primary objective is to examine the suitability of the cenosphere (CS; 0–30 Wt.%) to develop a high-quality lightweight composite structure with improved abrasion strength.Design/methodology/approachCS/polyethylene terephthalate glycol (PETG) composite feedstock filaments under optimized extrusion conditions were developed, and a fused filament fabrication process was used to prepare CS-filled PETG composite structures under optimal printing conditions. Significant parameters such as CS (0–30 Wt.%), sliding speed (200–800 rpm) and typical load (10–40 N) were used to minimize the dry sliding wear rate and coefficient of friction for developed composites.FindingsThe friction coefficient and specific wear rate (SWR) are most affected by the CS weight percentage and applied load, respectively. However, nozzle temperature has the least effect on the friction coefficient and SWR. A mathematical model predicts the composite material’s SWR and coefficient of friction with 87.5% and 95.2% accuracy, respectively.Practical implicationsBecause of their tailorable physical and mechanical properties, CS/PETG lightweight composite structures can be used in low-density and damage-tolerance applications.Social implicationsCS, an industrial waste material, is used to develop lightweight syntactic foam composites for advanced engineering applications.Originality/valueCS-reinforced PETG composite filaments were developed to fabricate ultra-light composite structures through a 3D printing routine.

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 &lt; 0.05) factors affecting the product's functional and physicochemical properties. The expansion property of extrudate significantly (p &lt; 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.

Physical and Functional Characteristics of Extrudates Prepared from Quinoa Enriched with Goji Berry

In this research, the possibilities of applying the extrusion process to produce functional food from quinoa enriched with goji berries were studied. The physical (expansion ratio, bulk density, hardness, and specific mechanical energy) and functional (water solubility index, water absorption index) characteristics were determined and optimized by the response surface methodology. Extrudates were produced using a laboratory single-screw extruder. The full factorial experimental design was used (N = 22) with three complementary center points to show the interactions of the amount of goji berry (1, 3, and 5%) and the feed moisture content (13, 16, and 19%) of the mixture on the physical and functional characteristics. Increasing moisture content from 13 to 19% resulted in extrudates with a lower expansion ratio, water absorption index, water solubility index, specific mechanical energy, and higher density and hardness. Increasing the amount of goji berries from 1 to 5% led to a decrease in expansion ratio, water absorption index, and hardness, and an increase in density, water solubility index, and specific mechanical energy. Optimal extrusion conditions for production of extrudates from quinoa enriched with goji berry were 16.3% feed moisture content and 1.32% goji berry’s amount.

Experimental Research on Optimization Extruder Process Parameters for Pineapple Pomace-Based Fish Feed

A single screw water-cooled jacketed extruder has been proposed to produce the fruit waste extrusion process of fish feed because of its superficial characteristics. This research mainly examined the effects of various extrusion conditions: feeding rate, screw speed, feed moisture, barrel temperature, cutting speed, and die open surface area. While maintaining the feed specifications (38% proteins and 5% lipids), four formulations with different pomace inclusions were obtained. The processing methodologies (with mash moisture and varied extruder parameters) were then based on three fundamental aspects (machine torque, apparent viscosity, and efficiency). They were studied using Response Surface Methodology (RSM). The influence of screw speed, moisture, and pomace inclusion was most significant. Optimum extrusion conditions were found at a feed rate of 1.47 kg.min-1, screw speed of 356.44 rpm, humidity of 16.04%, temperature of 60 °C, cutting speed of 1300 rpm, pomace inclusion rate of 10.59%, and an open surface die obtained 88.63%. The maximum desirable value of 0.61 resulted in 444.16 Nm-1 torque, 1008.98 Pa-s apparent speed, and 75.21% efficiency. The extruder evaluation demonstrated remarkable performance in producing pineapple pomace extrudates without impeding machine operating principles, redefining the robustness of extrusion process factors and their interactions in the process state.

Improvement of active peptide yield, antioxidant activity and anti-aging capacity of rapeseed meal fermented with YY-112 pure fermentation and co-fermentation

A study was carried out to increase the active peptide yield by fermenting with screened Bacillus subtilis YY-112, and investigate the nutrient compositions, antioxidant activity and anti-aging capacity in vitro between screened Bacillus subtilis YY-112 fermentation and co-fermentation with S.cerevisiae YY-21. The objective was to establish a novel method to obtain more active peptides to be used as functional food ingredients to resist aging, and investigate the best way for the rapeseed meal fermentation (pure fermentation and co-fementation). The B. subtilis YY-11 was screened and bred as B. subtilis YY-112 by the mutagenesis. The peptide concentration of the RSM fermented extruded RSM (FERSM) with B. subtilis YY-112 increased up to 231.75 mg/g (P < 0.001), and the specific surface area of the FERSM with pure B. subtilis YY-112 fermentation was significantly larger than that of the co-FERSM with S.cerevisiae YY-21 (P < 0.05). The ratio of the molecular weight (<5Da) of the FERSM with pure B. subtilis YY-112 was lower than that of the co-FERSM with S.cerevisiae YY-21 (P < 0.05), and the reducing capacity of the FERSM was significantly higher (P < 0.05). The cells induced by d-galactose fed the rapeseed peptides produced from the FERSM and co-FERSM exhibited higher T-AOC and T-SOD capacity (P < 0.05) and presented lower concentrations of malondialdehyde (MDA) (P < 0.05), and the concentrations of MDA fed the peptides from the FERSM were lower than those from the co-FERSM. Overall, the novel fermentation method with screened Bacillus subtilis YY-112 and optimized extrusion conditions were effective in improving the antioxidant activity and anti-aging activity in vitro, thereby increasing the added value of RSM.

Tortillas made from nixtamalized maize and extruded chickpea flours: A product with improved in vitro nutritional and antihypertensive properties

AbstractBackground and ObjectivesIn this study, tortillas with improved in vitro nutritional and antihypertensive properties were developed using flours produced from nixtamalized maize (NixM) and extruded chickpea (ExtCP). The aims were (1) to find the optimal extrusion conditions to produce optimized ExtCP flour with high values of antioxidant activity (AoxA), total phenolic compounds (TPC), and in vitro protein digestibility (IVPD), and (2) to evaluate the addition effect of 30% of optimized ExtCP flour over the nutritional, technological, sensory y nutraceutical properties of tortillas prepared from commercial NixM flour. A rotatable composite central experimental design with two factors (extrusion temperature [ET] = 50°C–170°C; screw speed (SS) = 50–240 rpm) and five levels was used to optimize the extrusion process.FindingsThe best combination of variables of the extrusion process to produce ExtCP flour was: ET = 143°C/SS = 138 rpm. The tortillas added with ExtCP flour had: proteins = 13.27%, total dietary fiber = 13.40%, protein chemical score = 85.42%, IVPD = 82.01%, calculated protein efficiency ratio (C‐PER) = 1.84, AoxA = 8031 µmol TE/100 g, and sensory acceptability = 8.51 (value located between I like it very much and I like it extremely).ConclusionsThe tortillas made from nixtamalized maize and ExtCP flours have better in vitro nutritional and antihypertensive properties than tortillas prepared from only nixtamalized maize flour.Significance and NoveltyThe addition of optimized ExtCP flour to commercial NixM flour allows obtaining functional tortillas with improved and sensory acceptable in vitro nutritional and antihypertensive properties.

Functional gluten-free beverage elaborated from whole quinoa and defatted chia extruded flours: antioxidant and antihypertensive potentials

The current market demands gluten-free (GF) foods with better nutritional/nutraceutical value. In this study, a functional GF beverage (GFB) from a flours mixture of optimized extruded quinoa (OEQ) (70%) and extruded defatted chia (EDC) (30%) was developed. To obtain OEQ, a central composed experimental design with two factors (extrusion temperature [TE] = 60 °C-140 °C and screw speed [VT] = 60 rpm-240 rpm) and three responses (antioxidant activity [AoxA], total phenolic compounds [TPC], and in vitro protein digestibility [IVPD]) was used. The optimal extrusion conditions for OEQ were 138 °C/138 rpm, and for EDC they were 147 °C/237 rpm (obtained in a previous work). The mixture had calculated protein efficiency ratio (C-PER) = 2.28 and angiotensin-converting enzyme (ACE) inhibitory potential (IC50) = 0.271 mg/ml. 200 ml of functional GFB contains 5.61 g of good quality protein, 6.13 g of dietary fiber, 88 kcal, and AoxA = 5091 µmol TE. The functional GFB is a healthy alternative for celiac people.

Feasibility of Extruded Brewer's Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet.

This study aimed to determine the effect of the extrusion process on the nutritional and bioactive profiles of brewer’s spent grain (BSG), contributing to nutrition security by applying a circular economy concept. Response surface methodology was used to optimize the effect extrusion parameters (moisture content, screw speed, and barrel temperature ) had on BSG’s soluble dietary fiber, free glucose, and overall antioxidant capacity. Proximate composition analyses, amino acid profile, extractable polyphenolic content, and antioxidant capacity of BSG and brewer’s spent grain extruded under optimal conditions (BSGE) were carried out. Food safety was analyzed by their microbiological quality, gluten, and acrylamide content. Optimal extrusion conditions were 15.8% of moisture content, 164.3 revolutions per min and 122.5 °C. BSGE presented 61% more soluble dietary fiber than BSG, lower digestible starch, 0.546% of free glucose, and protein quality parameters mostly like those reported for egg, soy, and milk. Despite this, BSG’s overall antioxidant capacity was not improved after thermomechanical processing; BSGE had significantly higher extractable polyphenolic content in its alkali extracts, which were determined qualitatively by high-performance liquid chromatography quadrupole time-of-flight assay in its hydro-alcoholic acid extracts. Furthermore, although it is not gluten free, BSGE is a safe food ingredient with acceptable microbiological quality and no acrylamide.

Effect of forming conditions on microstructure and room-temperature mechanical characterization of Zn–22Al superplastic microtubes fabricated by direct extrusion

The Zn–22Al alloy was processed under different microextrusion conditions to fabricate long and smooth microtubes with good strength and ductility. After direct microextrusion, the outer diameter variation and microstructure evolution of micro-extruded Zn–22Al microtubes under different extrusion conditions were investigated, followed by tensile tests at ambient temperature. With an increase in extrusion temperature and a decrease in extrusion speed, the microhardness, elongation, and tensile strength of the Zn–22Al microtubes decreased. The optimal extrusion conditions including temperature and speed for the microtubes were 250 °C and 1 mm/min, respectively, which were selected for preparing billet microtubes in the following process for fabricating microneedles. The mechanical behavior can be controlled by the microstructure of the extruded microtubes. The extruded microtubes at 340 °C and 1 mm/min had the highest tensile strength and hardness owing to the thinner lamellar structure, whose composition was analyzed by EDS.

Optimization of Fibre and Protein Rich Extruded Soybean-Rice Based Ready to Eat Snacks

Ready to eat, nutritious and low-cost snack was developed by composite flour containing defatted soya, rice, salt, radish leaves and pea pods powder. The best possible combination of process parameter was obtained with response surface methodology (RSM) using Box Behnken design. The different process variables viz., screw speed, die temperature, feed moisture and composition of base and supplement materials were optimized to obtain good quality soybean-rice based snack food. The designed experimental runs were conducted to obtain the optimal conditions as 360.42 rpm speed of screw (SS), 152.29°C die temperature (DT), 13.17% feed moisture (FM), 35% vegetable waste-soy powder (VW-SP) proportion and 65% of base flour. The results revealed that the addition of vegetable waste (radish leaves and pea pods powder) and soy powder had the most significant impact on all process variables followed by the feed moisture content. The blend proportion under optimum extrusion conditions had improved the nutritional quality of snack food with 1.55g/ 100g of fiber and 20.61g/100g of protein content and overall acceptability of 78.41%.

β-glucan rich functional instant talbina (porridge) premix from barley flour using extrusion: investigating effect of varied moisture and barrel temperature levels using response surface approach

PurposeThroughout the world, there has been a dramatic increase in the demand for functional food products. Owing to the health benefits of barley, its utilization was explored for the development of β-glucan rich functional instant talbina (porridge). The present research was, therefore, undertaken with an aim to optimize the extrusion conditions for development of instant talbina premix and evaluate its functional and quality characteristics.Design/methodology/approachThe independent variables i.e. barrel temperature (105–125°C) and feed moisture (12–20%) were studied to determine their influence on the system parameter i.e. specific mechanical energy and product characteristics i.e. bulk density, breaking strength, water absorption index, expansion ratio, water solubility index, L*, a* and b* by employing a central composite rotatable design.FindingsAll the quality parameters were significantly (p &lt; 0.05) influenced by independent variables. The regression models obtained for all the responses showed higher coefficient of determination (R2 = 0.99). The optimum extrusion conditions obtained by numerical optimization for development of extrudates used for making instant talbina were moisture content (12%) and barrel temperature (105°C). Various functional, pasting, complexing index and physicochemical properties of instant talbina were improved by the addition of honey and milk. The instant talbina prepared from barley flour with the addition of milk and honey showed increase in the β-glucan content, resistant starch, antioxidant activity and decrease in glycemic index with improved overall acceptability.Originality/valueAs far as we could possibly know that very limited or not many studies have been carried out wherein the possibility of developing instant talbina (porridge) have been carried out. As a result, the current study has a lot of potential for the food industry to manufacture β-glucan rich functional instant talbina with improved antioxidant characteristics and low glycemic index.

Effect of extrusion and fused filament fabrication processing parameters of recycled poly(ethylene terephthalate) on the crystallinity and mechanical properties

The production of plastic has grown exponentially over the past few decades and with it the amount of plastic waste leaking in the environment, where it fragments into micro- and nanoplastics. This problematic situation stresses the need for increased plastic collection, recycling and reuse rates. Extrusion-based additive manufacturing (AM) and especially fused filament fabrication (FFF) offer an efficient and effective method to reuse and upcycle recycled plastic. This study focuses on poly(ethylene terephthalate) (PET), which has a broad application window and its recycling is therefore environmentally and economically favorable and sustainable. Therefore, this study involves the thermal and mechanical behavior of recycled PET after extrusion and 3D printing. The extrusion parameters are optimized by performing a complete physico-chemical and thermal analysis of the obtained filaments and they were compared with commercial virgin and recycled PET. Moreover, the influence of the applied processing conditions on the degree of crystallinity and mechanical properties is investigated. The filaments are then used for FFF, where various printing parameters are altered to obtain the optimum printing conditions (i.e. printing temperature, the build plate temperature, fan cooling and printing directions). The effect of the degree of crystallinity of semi-crystalline PET is investigated via altered printing parameters, showing superior mechanical properties for an increasing degree of crystallinity. To verify the portability of the obtained optimized print parameters, two different FFF printers are used. The use of recycled PET as feedstock for FFF supports the efforts for improving the sustainability of plastics by valorizing PET waste, and prolonging the lifecycle of PET. • Optimized extrusion conditions for recycled poly(ethylene terephthalate) filaments. • Reduced shrinkage of printed rPET parts via increased build plate temperature. • Printed rPET parts proved to be anisotropic in terms of tensile modulus. • Improved mechanical properties obtained via controlling the degree of crystallinity.

Development of Functional Snack Food from Almond Press Cake and Pearl Millet Flour

Defatted almond cake (DAC), a major by-product of the almond oil industry, was explored in combination with pearl millet (PM) to develop functional snack food using extrusion technology. The optimum extrusion conditions for developing snacks from DAC (20%) and PM (80%) flour blends were determined through a numerical optimization technique. The optimized product was evaluated for various quality parameters. The expansion ratio of 3.56, bulk density 0.11g/cm3, hardness 30.55N, water absorption index 6.22g/g, and water solubility index 14.56% indicates that its physical characteristics were in the desirable range, while total phenol content of 56.91 ± 2.09 (mg GAE/100g), total flavonoid content of 18.29 ± 0.4 (QE/100g) and DPPH radical scavenging activity (total antioxidant activity) of 89.74± 0.8% indicates its superior bioactive properties. Production and consumption of such snack types on a large scale can improve the population's nutritional status, besides adding value to the defatted almond cake.