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This paper aims to understand the effect of extrusion conditions on the degree of foaming of polylactic acid (PLA) during three-dimensional (3D) printing. It was also targeted to optimize the slicing parameters for 3D printing and to study how the properties of printed parts are influenced by the extrusion conditions.

This study used a commercially available PLA filament that undergoes chemical foaming. An extrusion 3D printer was used to produce individual extrudates and print samples that were characterized using an optical microscope, scanning electron microscope and custom in-house apparatuses.

The degree of foaming of the extrudates was found to strongly depend on the extrusion temperature and the material feed speed. Higher temperatures significantly increased the number of nucleation sites for the blowing agent as well as the growth rate of micropores. Also, as the material feed speed increased, the micropores were allowed to grow bigger which resulted in higher degrees of foaming. It was also found that, as the degree of foaming increased, the porous parts printed with optimized slicing parameters were lightweight and thermally less conductive.

This study fills the gap in literature where it examines the foaming behavior of individual extrudates as they are extruded. By doing so, this work distinguishes the effect of extrusion conditions from the effect of slicing parameters on the foaming behavior which enhances the understanding of extrusion of chemically foamed PLA.

This study aimed to evaluate the enrichment with UD powder effects on phenols, antioxidant capacity, color, texture and extrusion parameters of extruded snacks.

Extrudates were produced with a single-screw extruder. It operated at a 3:1 compression ratio, loaded with prepared corn samples at a constant dosing speed of 18 rpm. The screw was rotated constantly at 150 rpm and temperatures of barrel sections 1–4 were set to 25, 70, 170 and 175°C, respectively; the nozzle diameter was 3 mm.

Extrudate parameters were fitted against UD concentration and presented equations close to the experimental data, according to the obtained adjusted R². Using UD powder in the mixture to obtain extruded corn snacks increased their phenols content and antioxidant capacity. However, high UD concentration in the mixtures caused low expansion and porous extrudates; nevertheless, it lowered possible molecular damage risk by molecules solubilized in water, making them more stable. Using 7.5% UD percentage in mixtures is recommended for extruded snacks to maintain typical extrudate characteristics. Higher UD concentration provokes more hygroscopic, dense and compact snacks.

These findings confirm that using U. dioica L. powder in the mixture to obtain extruded corn improves the functional value of snacks, maintaining extruded characteristics.

This study aims to develop sweet chestnut incorporated corn-based extrudates by the optimization of process conditions.

The independent process variables for extrusion (blend ratio, barrel temperature, screw speed and feed moisture) were investigated to govern their impact on reliant variables, namely, bulk density, specific mechanical energy, water absorption index, water solubility index, color and hardness. Product and system responses were significantly (p < 0.05) affected by the independent variables. Experimental design with quadratic models experienced a high coefficient of determination (R² = 0.99).

Numerical optimization for the development of extrudates resulted in optimum conditions having corn flour: sweet chestnut flour (80:20), barrel temperature (120°C), screw speed (340 rpm) and feed moisture (12%). Fat, moisture and protein contents of the developed extrudates using optimum conditions were significantly (p < 0.05) lower compared to raw materials – corn and sweet chestnut. The packaging of extrudates in aluminum laminates revealed shelf stability of three months at room temperature without deterioration of quality.

Nutritionally rich sweet chestnut extruded products would be an exclusive option to already existing snacks in the market and can facilitate a new sphere in extruded product sector.

Throughout 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.

The 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.

All the quality parameters were significantly (p < 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.

As 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.

The purpose of this study was to formulate a complete protein food from lentil flour (LF) and egg powder (EP) through microwave-assisted extrusion technology.

In the first part of the hybrid technology, the feed proportion and extrusion conditions were optimized through design expert using central composite rotatable design. In the second part of hybrid technology, the optimized protein pellets (PP) obtained were subjected to microwave heating (MH) for 50,100, 150, 200 and 250 s.

The optimum predicted conditions for development of pellets using extrusion cooking were feed proportion (85% LF and 15% EP), barrel temperature (140°C), screw speed (340 rpm) and feed moisture content (12%). When these pellets were subjected to MH, 150 s of heating time was considered as prudential to induce desirable quality changes in PP. The increase in sectional expansion index, crispness and overall acceptability from 0.637 to 0.659, 4.51 to 6.1 and 3.27 to 3.59 with corresponding decrease in bulk density and breaking strength from 73.33 to 69.75 kg/cm³ and 6.24 to 5.13 N during 150 s of MH indicated that quality characteristics of extruded PPs were improved after MH.

Nowadays, consumers have become more health conscious than ever, and the demand for nutritious snacks has increased many folds. However, the high protein content restricts expansion of snacks, which was overcome by subjecting extruded pellets to MH to produce third generation pellets. Furthermore, the PP has a protein content of 31.62%, which indicates that if an average person consumes 100 g of these snacks, it will suffice 60% of total recommended dietary intake (0.75 g/kg body weight/day). Lentil-based pellets expanded by use of such hybrid technology (microwave-assisted extrusion cooking) can help to provide a feasible, low cost and protein-rich diet for malnourished population besides being a value addition to lentils.

LF in combination with EP was tested for the first time for development of nutrient dense pellets. Moreover, use of microwave-assisted extrusion cooking offers a workable and innovative technique of developing protein-rich pellets with improved physico-chemical and sensory attributes.

The purpose of this study was to evaluate the effects of the addition of flaxseed and amaranth at different proportions on the hydration kinetics, colour and sensory qualities of instant-extruded cereals, important aspects related to the functionality and acceptability of food products.

Instant-extruded cereals were made with different proportions of flaxseed (6.6–9.3%), amaranth (18.7–33.1%), and maize grits (63.8–67.3%); and characteristics such as hydration kinetics, colour parameters and sensory properties were evaluated.

The kinetics of milk absorption showed that the extruded cereals maintained their texture and crispness for a sufficiently long time (≤20 min). The L*, a* and chroma* values of the extruded cereals were significantly affected (p < 0.05) by the flaxseed content. Sensory evaluation showed that all the extrudates had good acceptance in terms of flavour, texture, and colour attributes in relation to high-fibre commercial cereals; according to the preference test, they were as acceptable as commercial extruded cereals when consumed with milk. The addition of high-fibre and protein-containing grains such as flaxseed (8.6–9.3%) and amaranth (18.7–22.9%) in instant-extruded cereals allowed the production of products with acceptable physical and sensory characteristics.

In this study a novel instant-extruded cereal with flaxseed and amaranth was developed. The evaluation of the physical and sensory characteristics of instant-extruded cereals is essential to guarantee consumer acceptability, especially if functional ingredients with a high content of dietary fibre and protein are added.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

The purpose of the paper is to describe the production of traditional fura and extruded fura blends from 100 per cent pearl millet flour and blends of pearl millet flour with three‐grain legume flour mixtures, i.e. cowpea, soybean, and groundnut at 20 and 30 per cent levels each and to evaluate the influence of extrusion process' on products hydration properties.

Traditional methods of flour preparation were adopted. Extrusion was performed in a single‐screw Brabender Extruder.

The bulk density of traditional fura significantly differed from those of the extrudates (P<0.05). Extrudates exhibited instantization tendency, i.e. ability of easy preparation before eating without the usual rigorous labour involved in the traditional method. Pearl millet: cowpea fura (80:20) had the highest puff ratio of 4.71 while the pearl millet: groundnut (70:30) fura had the least puff ratio, 2.90. Samples with high fat content appear to have lower puff ratio. There were no significant differences in the wettabilities of extruded fura samples (P<0.05) at 28⁰C with the exception of millet: groundnut (70:30) indicating differences (P<0.05) in wettabilities at 50^oC. There were significant differences (P<0.05) in swelling capacities of fura products at each level of water added. The hydration power of extrudates varied significantly (P<0.05) for products both at 28^o and 50^oC; and 100 per cent fura extrudate had the highest hydration power value 63.92 at 28^oC, while traditional fura had the least value, 15.80.

Extrusion cooking revealed good potential opportunities for the manufacture of commercial instant fura and the potential of better storage as a result of low moisture content.

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF³) of Ti-6Al-4V. Additionally, an empirical method was presented for the estimation of extrudate deflection in unsupported regions of lattice cells for different geometric configurations.

Metal-polymer feedstock with a solids-loading of 59 Vol.% compounded and extruded into a filament was used for three-dimensional printing of lattice structures. A unit cell was used as a starting point, which was then extended to multi-stacked lattice structures. Feasible MF³ processing conditions were identified to fabricate defect-free lattice structures. The effects of lattice geometry parameters on part deflection and relative density were investigated at the unit cell level. Computational simulations were used to predict the part quality and results were verified by experimental printing. Finally, using the identified processing and geometry parameters, multi-stacked lattice structures were successfully printed and sintered.

Lattice geometry required considerable changes in MF³ printing parameters as compared to printing bulk parts. Lattice cell dimensions showed a considerable effect on dimensional variations and relative density due to varying aspect ratios. The experimental printing of lattice showed large deflection/sagging in unsupported regions due to gravity, whereas simulation was unable to estimate such deflection. Hence, an analytical model was presented to estimate extrudate deflections and verified with experimental results. Lack of diffusion between beads was observed in the bottom facing surface of unsupported geometry of sintered unit cells as an effect of extrudate sagging in the green part stage. This study proves that MF³ can fabricate fully dense Ti-6Al-4V lattice structures that appear to be a promising candidate for applications where mechanical performance, light-weighting and design customization are required.

Supportless printing of lattice structures having tiny cross-sectional areas and unsupported geometries is highly challenging for an extrusion-based additive manufacturing (AM) process. This study investigated the AM of Ti-6Al-4V supportless lattice structures using the MF³ process for the first time.