Back Extrusion Research Articles

Microstructure Evolution and Corrosion Resistance of As-Extruded AZ91–Ca Alloy During Friction Stir Back Extrusion

Microstructure Evolution and Corrosion Resistance of As-Extruded AZ91–Ca Alloy During Friction Stir Back Extrusion

Effects of Particle Size and Shape on the Texture Property of a Solid-Liquid Dispersion System With Gel Particles.

Food texture is one of the most important factors for assessing the quality and acceptability of food. However, the study of food texture has been delayed compared with other factors, such as flavor and taste, due to the difficulty of quantitative analysis related to real physiological senses. Furthermore, the numerical and systematic evaluation of the texture property of dispersion systems, in which solid particles are dispersed in a liquid medium, is very difficult, despite most foods being in a solid-liquid dispersion state during mastication in the human mouth. In this study, the texture property of a solid-liquid dispersion system with spherical and cubic gel particles of agar and konjac was examined to evaluate the physical behavior of food during mastication using the back extrusion method. The yield stress of the system strongly depended on the size and shape of the particles, the mixing ratio of particles of different sizes and shapes, and the concentration of components in the particles. The proposed index, reflecting the size, shape, and number of particles and the yield stress of a single particle, expressed well the measured yield stress of the entire dispersion system. However, the adhesiveness and recoverability showed relatively little dependence on particle size. The findings obtained in this study will contribute to elucidating the texture property of various foods and to the development of new and novel food products and cuisines, thereby benefiting food science and industry.

Impact of Sourdough from a Commercial Starter Culture on Quality Characteristics and Shelf Life of Gluten-Free Rice Breads Supplemented with Chickpea Flour.

This study aimed to develop a novel gluten-free bread using a rice/chickpea flour-based sourdough, fermented by a commercial starter culture, to improve the quality characteristics and shelf life of this product. The effects of sourdough incorporation, chickpea flour content (6.5 and 10.0%), and added water level (80-110%) on batter rheology and bread quality were investigated; bread textural characteristics upon storage (0-2 days) were also monitored. The level of added water was the primary factor influencing batter rheology, as evaluated by the back extrusion test. Sourdough incorporation decreased the pH and increased the acidity of batters and breads. The inclusion of sourdough, the water level, and the storage time affected the moisture and texture parameters of the bread crumb. Sourdough incorporation into bread formulations decreased crumb hardness and staling rate and increased loaf specific volume. Moreover, intermediate water (90 and 100%) and high chickpea (10%) levels in the batters increased loaf specific volumes and crust redness, respectively. Sensory analysis revealed that sourdough-enriched breads were preferred by the assessors concerning general appearance and crumb texture. Overall, bread formulations with the incorporation of sourdough, at a 90% level of added water in the batter mixtures, exhibited the most desirable characteristics according to both instrumental and sensory analyses.

A new dietary low-fat custard formulation made by waxy corn starch and xylitol: Rheological, sensory and in vitro digestibility investigation

Custard is a dairy starch-based dessert, in which presence of milk increases its nutritional value and sensitivity to freezing, pH, and storage. Producing a custard with less phase separation during storage and improving its functionality is challenging. The present study has investigated the effect of starch type (native corn starch and waxy corn starch), fat content (2.67% & 0.1%) and sucrose-xylitol ratio (1:0, 1:1, 0:1) on rheological, textural, enzyme digestibility and sensory properties of custard desserts. The back extrusion test showed a significant increase in consistency (40.60 mJ) by using xylitol and decreasing fat content compared to the control sample (2.16 mJ). Also, applying waxy corn starch diminished hardness (1.66 N) compared to the control (13.55 N), which was accompanied by a decrease of syneresis after five days of storage from 10.29% to 0.02% and improvement of sensory properties of creaminess, smoothness and taste intensity. Accordingly, low-fat custard formulation containing waxy corn starch and xylitol indicated high creaming stability (98.08%), adhesiveness (9.45 mJ), viscosity at a constant shear rate of 50 s−1 (3.58 Pa s), and water holding capacity after five days of storage at 4 °C (99.99%) and thickness (9.53). Also, xylitol reduced custards’ glucose release after amylase objection.

Evaluation of Emulgel and Nanostructured Lipid Carrier-Based Gel Formulations for Transdermal Administration of Ibuprofen: Characterization, Mechanical Properties, and Ex-Vivo Skin Permeation

In transdermal applications of nonsteroidal anti-inflammatory drugs, the rheological and mechanical properties of the dosage form affect the performance of the drug. The aim of this study to develop emulgel and nanostructured lipid carrier NLC-based gel formulations containing ibuprofen, evaluate their mechanical properties, bioadhesive value and ex-vivo rabbit skin permeability. All formulations showed non-Newtonian pseudoplastic behavior and their viscosity values are suitable for topical application. The particle size of the nanostructured lipid carrier system was found to be 468 ± 21 nm, and the encapsulation efficiency was 95.58 ± 0.41%. According to the index of viscosity, consistency, firmness, and cohesiveness values obtained as a result of the back extrusion study, E2 formulation was found to be more suitable for transdermal application. The firmness and work of shear values of the E2 formulation, which has the highest viscosity value, were also found to be the highest and it was chosen as the most suitable formulation in terms of the spreadability test. The work of bioadhesion values of NLC-based gel and IBU-loaded NLC-based gel were found as 0.226 ± 0.028 and 0.181 ± 0.006 mJ/cm2 respectively. The percentages of IBU that penetrated through rabbit skin from the Ibuactive-Cream and the E2 were 87.4 ± 2.11% and 93.4 ± 2.72% after 24 h, respectively. When the penetration of ibuprofen through the skin was evaluated, it was found that the E2 formulation increased penetration due to its lipid and nanoparticle structure. As a result of these findings, it can be said that the NLC-based gel formulation will increase the therapeutic efficacy and will be a good alternative transdermal formulation.Graphical

Assessing texture profile analysis in natural state versus texture profile analysis with back extrusion post-homogenization of cooked pea protein-based and meat patties: A comparative study

This study aims to evaluate the efficacy of Texture Profile Analysis on homogenized cooked patties, referred to as TPAH, in accurately predicting patty texture and distinguishing between various patty types, similar to traditional TPA. Eight types of patties (96 samples), comprising one meat patty, one commercial pea protein-based patty, and six homemade pea protein-based patties, underwent analysis for hardness, cohesiveness, gumminess, chewiness, resilience, and springiness. All parameters measured by both methods exhibited similar variations, except for springiness. Homogenization maintained the ability to differentiate between different types of patties and generally reduced the load, albeit in a manner dependent on the type of product. For instance, the hardness decreased from 32.6 to 29.6 N for the meat patty, from 18.7 to 10.0 N for the homemade patties, and from 17.4 to 5.0 N for the commercial patty. The meat patty exhibited a greater consistency with a 9.2 % drop, while the homemade vegetable patties experienced a drop of 46.5 %, and the commercial patty even more so with 71.3 %. Canonical Discriminant Analysis applied to the two methods demonstrated the superior performance of TPAH compared to TPA. The TPAH method has proven to be valuable in predicting and comparing the texture of cooked patties.

Development of “clean label” gluten-free breads fortified with flaxseed slurry and sesame cake: Implications on batter rheology, bread quality and shelf life

Following the recently emerged trends for products without additives and valorization of food processing by-products, “clean label” gluten-free (GF) breads were developed using a flaxseed slurry (FS) at 3% or 4.5% level (flaxseed basis), instead of the commonly used structurant in GF doughs, methylcellulose, and 3 or 6% (flour mixture basis) sesame cake (SC) for further product nutritional improvement. These alternative ingredients increased batter hardness and cohesiveness (back extrusion test) as well as elastic modulus, complex and steady shear viscosity (rheometry), compared to formulation containing only methylcellulose (control). The fortified breads had lower loaf specific volumes, than the control, but significantly higher than a GF bread made without any added hydrocolloid. FS and SC enhanced the formation of β-sheet structures (FTIR spectroscopy) in the batter and bread protein matrix. FS breads exhibited similar crumb hardness, cohesiveness, and springiness (TPA test) with the control, whereas inclusion of SC compromised these textural attributes. Nevertheless, the latter samples showed less pronounced textural changes upon storage (25°C-48 h), with similar extent of staling to control. For the fortified stored breads, there were no significant changes in protein conformation, compared to fresh products, whereas crumb starch retrogradation (calorimetry-DSC) was lower than the control. Additionally, the FS and SC increased the protein and dietary fiber contents and introduced nutty and sesame-like flavor notes to the breads, leading to improved overall acceptability scores. Overall, FS and SC seemed to be promising functional ingredients for the development of “clean label” GF breads with enhanced quality and shelf life.

Numerical Analysis of Process Parameters and Tool Geometry in Friction Stir Back Extrusion of Pure Aluminum

Friction Stir Back Extrusion (FSBE) is an innovative process that offers efficient aluminum waste recycling and wire production. This process boasts economic and environmental advantages, as it requires minimal energy compared to traditional recycling casting methods. The objective of this study is to analyze the impact of process parameters using a Finite Element Method (FEM) model based on thermo-mechanical 3D Lagrangian. The study focuses on an AA1080 aluminum alloy and employs different geometric tools, including hole extrusion diameters of 4 mm and 8 mm, as well as a shoulder with two distinct angles of 10° and 15°. Furthermore, variations in several process parameters, such as a constant axial feed rate of 0.5 and 1 mm/min and a constant rotational speed of the die set at 100, 300, and 500 rpm, are considered. The simulation plan encompasses a total of 24 combinations of these parameters to identify the optimal conditions for chips extrusion. Subsequently, the obtained results were analyzed using Design of Experiments (DoE) analysis to assess the influence of each parameter on peak force, torque, and temperature during the process.

Modeling Textural Properties of Cooked Germinated Brown Rice Using the near-Infrared Spectra of Whole Grain.

If a non-destructive and rapid technique to determine the textural properties of cooked germinated brown rice (GBR) was developed, it would hold immense potential for the enhancement of the quality control process in large-scale commercial rice production. We combined the Fourier transform near-infrared (NIR) spectral data of uncooked whole grain GBR with partial least squares (PLS) regression and an artificial neural network (ANN) for an evaluation of the textural properties of cooked germinated brown rice (GBR); in addition, data separation and spectral pretreatment methods were investigated. The ANN was outperformed in the evaluation of hardness by a back extrusion test of cooked GBR using the smoothing combined with the standard normal variate pretreated NIR spectra of 188 whole grain samples in the range of 4000-12,500 cm-1. The calibration sample set was separated from the prediction set by the Kennard-Stone method. The best ANN model for hardness, toughness, and adhesiveness provided R2, r2, RMSEC, RMSEP, Bias, and RPD values of 1.00, 0.94, 0.10 N, 0.77 N, 0.02 N, and 4.3; 1.00, 0.92, 1.40 Nmm, 9.98 Nmm, 1.6 Nmm, and 3.5; and 0.97, 0.91, 1.35 Nmm, 2.63 Nmm, -0.08 Nmm, and 3.4, respectively. The PLS regression of the 64-sample KDML GBR group and the 64-sample GBR group of various varieties provided the optimized models for the hardness of the former and the toughness of the latter. The hardness model was developed by using 5446.3-7506 and 4242.9-4605.4 cm-1, which included the amylose vibration band at 6834.0 cm-1, while the toughness model was from 6094.3 to 9403.8 cm-1 and included the 6834.0 and 8316.0 cm-1 vibration bands of amylose, which influenced the texture of the cooked rice. The PLS regression models for hardness and toughness had the r2 values of 0.85 and 0.82 and the RPDs of 2.9 and 2.4, respectively. The ANN model for the hardness, toughness, and adhesiveness of cooked GBR could be implemented for practical use in GBR production factories for product formulation and quality assurance and for further updating using more samples and several brands to obtain the robust models.

Simulation research on the rotating back extrusion process for magnesium alloy wheel

Simulation research on the rotating back extrusion process for magnesium alloy wheel

Development of a Specific Lexicon to Describe Sensory and Textural Characteristics of Olive Paté

Olive paté is a traditional Italian food typical of the Mediterranean diet, derived from debittered, pitted, and crushed table olives. Currently, there is no sensory standard for the quality of the product. In this research, a specific lexicon and an innovative profile sheet for sensory analysis of olive paté have been developed and tested to fill the gap. The list of descriptors was set in terms of negative sensations, olfactory/gustatory sensations, and kinaesthetic attributes. The assessors of a professional panel were first trained with and then used the profile sheet to characterize 40 olive paté commercial samples from five different Olea europaea L. cultivars. From a sensorial point of view, Nocellara del Belice paté was perceived as the saltiest, Nocellara etnea as the bitterest, and Hojiblanca and Bella di Cerignola were the most balanced and characterized on the olfactory/gustatory level. In terms of texture, Hojiblanca paté is the most consistent and grainiest. To support and verify kinaesthetic descriptors, textural analysis by back extrusion was performed. Through the agglomerative hierarchical analysis, the various paté showed a clear clusterization into two clusters: Nocellara del Belice-Itrana and Hojblanca-Nocellara etnea-Bella di Cerignola. The results obtained showed the validity of the profile sheet to correctly assess the different products.

Texture profile analysis of homogenized meat and plant-based patties

ABSTRACT The objective of this study has been to verify whether a combination of the standard Texture Profile Analysis and the back extrusion, which we have named “TPAH” since the analysis was performed after homogenization, can be applied to products that are difficult to handle. The TPAH was applied to 180 samples, divided equally into 18 batches of home-made pea-based patties, commercially pea-based patties, and meat patties. Seven TPAH parameters were measured on both raw and cooked samples: adhesiveness, chewiness, cohesiveness, gumminess, hardness, springiness and resilience. The specific density of the raw and cooked samples as well as a few physico-chemical parameters were also measured. All TPAH parameters were able to clearly discriminate between home-made, commercial, and meat patties (P-value <.05 to 0.001). A Canonical Discriminant Analysis highlighted the effectiveness of TPAH on both raw patties (R2 = 0.960, Wilks’ Lamba test Pr < 0.0001) and cooked ones (R2 = 0.955, Wilks’ Lamba test Pr < 0.0001). Even when the Canonical Discriminant Analysis was narrowed to cooked plant-based patties, the method proved to be efficient (R2 = 0.809, Wilks’ Lamba test Pr < 0.0001). The protein content was significantly related to all the TPAH parameters, except for adhesiveness. The TPAH method could be useful in research related to the substitution of meat patties with plant-based ones.

Evaluation of Precision and Sensitivity of Back Extrusion Test for Measuring Textural Qualities of Cooked Germinated Brown Rice in Production Process.

The textural qualities of cooked rice may be understood as a dominant property and indicator of eating quality. In this study, we evaluated the precision and sensitivity of a back extrusion (BE) test for the texture of cooked germinated brown rice (GBR) in a production process. BE testing of the textural properties of cooked GBR rice showed a high precision of measurement in hardness, toughness and stickiness tests which indicated by the repeatability and reproductivity test but the sensitivity indicated by coefficient of variation of the texture properties. The findings of our study of the effects on cooked GBR texture of different soaking and incubation durations in the production of Khao Dawk Mali 105 (KDML 105) GBR, as measured by BE testing, confirmed that our original protocol for evaluation of the precision and sensitivity of this texture measurement method. The coefficients of determination (R2) of hardness, toughness and stickiness tests and the incubation time at after 48 hours of soaking were 0.82, 0.81 and 0.64, respectively. The repeatability and reproducibility of reliable measurements, which have a low standard deviation of the greatest difference between replicates, are considered to indicate high precision. A high coefficient of variation where relatively wide variations in the absolute value of the property can be detected indicates high sensitivity when small resolutions can be detected, and vice versa. The sensitivity of the BE tests for stickiness, toughness and hardness all ranked higher, in that order, than the sensitivity of the method for adhesiveness, which ranked lowest. The coefficients of variation of these texture parameters were 31.26, 20.59, 19.41 and 18.72, respectively. However, the correlation coefficients among the texture properties obtained by BE testing were not related to the precision or sensitivity of the test. By obtaining these results, we verified that our original protocol for the determination of the precision and sensitivity of food texture measurements which was successfully used for GBR texture measurement.

Effect of friction stir back extrusion on direction-dependent properties of gradient AZ91-bioactive glass composite rod

This research investigated the microstructure, mechanical properties, and corrosion resistance of friction stir back extruded AZ91-bioactive glass composites in parallel and perpendicular directions to the extrusion direction. The results showed that small grains are observed on the lateral surface, especially where bioactive glass is more prevalent. The grain size increases toward the center of the composite rod. The grain size and relative content of the β-Mg17Al12 phase shift from 30.2 ± 2.3 μm and 0.45 on the lateral surface of the composite rod to 37.4 ± 3.2 μm and 0.12 at the center of the composite rod, respectively. The corrosion resistance and hardness of the lateral surface area of the composite rod are 23 and 26%, respectively, higher than the corrosion resistance and hardness of the transverse surface. The lateral surface of the composite rod shows 74% higher corrosion resistance than the lateral surface of friction stir back extrusion processed wire without bioactive glass particles.

Inhomogeneity of the Backward Extruded NdFeB Ring Magnet Prepared from Amorphous Powders.

Back extrusion is an important process to prepare radially oriented NdFeB ring magnets. In this work, we fabricate the ring magnets using amorphous magnetic powders as the raw material. The microstructure, magnetic properties, corrosion resistance, and mechanical properties of the backward extruded magnet at different positions along the axial direction have been investigated, and the inhomogeneity of the magnet is clarified. The results showed that the grains in the middle region of the ring magnet exhibit a strong c-axis orientation, whereas the grains at the bottom and top regions are disordered with random orientation. The microstructure variation is related to the distribution of the grain boundary phase and the degree of grain deformation. Due to the microstructure difference, the magnetic properties, temperature stability, corrosion resistance, and mechanical properties in the middle region of the magnet are higher than those in the top and bottom regions. The exchange coupling between grains also varies in different regions, which is related to the grain size and grain boundary thickness. In addition, different Co element segregations were observed in different regions, which has a crucial effect on the Curie temperature and thermal stability of the magnet. The microstructure difference also leads to the variation of corrosion resistance and mechanical properties for the samples from different regions of the magnet. This work suggests that the amorphous powder can be used to directly prepare radially oriented ring magnets, and the inhomogeneity of the magnet should be fully understood.

Effect of friction stir back extrusion rotational speed on microstructure, mechanical properties, and corrosion behaviour of AZ91-Ca alloy

In this study, the effect of severe plastic deformation via friction stir back extrusion on microstructure, mechanical properties, and corrosion behavior of AZ91-Ca alloy were investigated. The results show that due to the high temperature during the process at a rotation speed of 1200 rpm, all the β-Mg17Al12, and Al2Ca phases are dissolved, and next to the manganese-rich compounds, re-precipitation of the β-Mg17Al12 and Al2Ca phases is observed. Also, increasing the rotation speed from 800 to 1200 rpm increases the accumulated strain from 0.186 to 0.351. With decreasing rotational speed from 1200 to 800 rpm, the texture parameter of the basal and prismatic planes is reduced, and on the contrary, the texture parameter of the pyramidal planes is increased. The ultimate tensile strength value increases from 332.14 ± 8.71 MPa to 375.13 ± 7.45 MPa by decreasing the rotational speed from 1200 to 800 rpm. The ultimate tensile strength, yield strength, elongation percent, and corrosion resistance in the sample processed at 800 rpm increased by 78, 49, and 32%, respectively, when compared to the as-cast base metal.

Impact of dry sourdough based on a fermented chickpea starter on quality characteristics and shelf life of gluten-free bread

The impact of drying of rice-chickpea flour sourdough (SD) made by a fermented chickpea extract (FCE) starter on rice flour-corn starch gluten-free (GF) batter and bread physicochemical properties were explored; FCE was prepared by submerged fermentation (37 °C × 15 h) of ground chickpeas. A liquid (freshly made) and two dried FCE-sourdoughs, dehydrated (air heating at 30 °C) or lyophilized, as well as a control formulation (without FCE-SD) were prepared at 80, 90, 100 and 110% (flour mixture basis) added water levels. Firmness, consistency, cohesiveness, and viscosity index of the batters, as evaluated by back extrusion testing, decreased by increasing the added water level in the formulation and increased by inclusion of the dehydrated sourdough preparation (p < 0.05). The lyophilized and liquid sourdough-containing breads exhibited the lowest pH and the highest specific volume, while dehydrated sourdough bread exhibited higher pH than the rest of the SD-containing breads and similar specific volume to that of control. Nevertheless, both dry FCE-SD preparations increased the crust redness and all FCE-SD breads had similar concentrations of butyric/isobutyric acids indicating a butyric fermentation during FCE preparation. Texture profile analysis revealed that both liquid and lyophilized sourdough improved crumb texture and retarded the bread staling process compared to control and dehydrated sourdough formulations (p < 0.05). The former products thus gained higher preference by a non-trained sensory evaluation panel. Overall, the lyophilized FCE-SD showed analogous potential with the liquid sourdough to improve quality attributes and shelf life of gluten-free breads, whereas the dehydrated FCE-SD (mild heating) did not fully retain its functionality.

Mechanism of plasticity enhancement of AZ31B magnesium alloy sheet by accumulative alternating back extrusion

Accumulative alternating back extrusion was a potential fine-grain modification method. In this paper, it was an innovative attempt to develop high-performance magnesium alloy sheet by this process. Under the condition of 350 K, commercial AZ31 magnesium alloy was made into billet by accumulative alternating back extrusion, and then extruded into fine-grain magnesium alloy sheet. Through a systematic study of its microstructure and mechanical properties, the results showed that the initial state had an important influence on the evolution of the structure during extrusion. After accumulative alternating back extrusion to produce the billet, the grain size of the sheet obtained by extrusion was significantly refined, which was related to the accumulation of deformation and grain refinement during the alternating loading process. Grain refinement caused the proportion of dynamic recrystallization inside the sheet with 2 cycles of accumulative alternating back extrusion to drop to 27%. With the increase of extrusion cycles from 2 to 4, the high density of dislocations led to an increase in the proportion of dynamic recrystallization and finer grains. The texture changed from strong basal texture to weak bimodal texture. The results of uniaxial tensile test show that due to grain refinement and texture change, the yield strength was significantly reduced, and the plasticity was significantly improved. It was verified that accumulative alternating back extrusion was meaningful for subsequent processing, and it also provided scientific guidance for the development of fine-grained magnesium alloy sheet.

Fabrication of new gradient AZ91-bioactive glass composite using friction stir back extrusion

This study investigated the microstructure, mechanical characteristics, and in vitro corrosion behavior of gradient AZ91-bioactive glass composite wire fabricated by friction stir back extrusion. The results showed that by decreasing the extrusion speed from 40 to 20 mm/min, the distribution factor of bioactive glass increased from 0.31 ± 0.04–0.45 ± 0.07, and more homogenous grain size was formed at the surface and center zone of the composite wire. Under the influence of heat and plastic deformation during friction stir back extrusion, despite the formation of the β-phase in separate islands, the α + β eutectic phase was also formed in the composite wire. In composite wire processed with a rotational speed of 800 rpm and extrusion speed of 20 mm/min, a gradient distribution of bioactive glass was formed in the cross section of the wire. Compared to an as-cast AZ91 alloy, friction stir back extrusion conducted at a rotational speed of 800 rpm and an extrusion speed of 20 mm/min resulted in a 44% increase in corrosion resistance in simulated body fluid (SBF).

Numerical simulation of billet height-diameter ratio on magnesium alloy automobile wheel formed by back extrusion

Numerical simulation of billet height-diameter ratio on magnesium alloy automobile wheel formed by back extrusion