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Cocoa pod husk (70–75 wt.% of the fruit) is a waste that can be used containing cellulose (c.a. 35.4 wt.%). The present work evaluates the valorization of cocoa pod husk as a potential source of cellulose to obtain carboxymethylcellulose. A yield of 21.9% of extracted cellulose was obtained with respect to the cocoa husk flour used. Different procedures were applied to obtain carboxymethylcellulose (CMC), followed by a purification process, achieving a yield of 64.3%. The physical characterization of the CMC obtained was carried out using FTIR spectroscopy, and its molecular weight (183628.89 g/mol) was determined by its intrinsic viscosity. The CMC dispersions were tested using small amplitude oscillatory shear (SAOS) for concentrations 3–7%, finding an evolution in the rheological behavior of the systems studied.

Seaweeds, rich in high-value polysaccharides with thickening/gelling properties (e.g., agar, carrageenan, and alginate), are extensively used in the food industry for texture customization and enhancement. However, conventional extraction methods for these hydrocolloids often involve potentially hazardous chemicals and long extraction times. In this study, three red seaweed species (Chondrus crispus, Gelidium Corneum, and Gracilaria gracilis) commercialized as food ingredients by local companies were chosen for their native gelling biopolymers, which were extracted using water-based methodologies (i.e., (1) hydration at room temperature; (2) stirring at 90 °C; and (3) centrifugation at 40 °C) for production of sustainable food gels. The potential use of these extracts as bioinks was assessed employing an extrusion-based 3D printer. The present work aimed to study the gelation process, taken place during printing, and assess the effectiveness of the selected green extraction method in producing gels. To improve the definition of the printed gel, two critical printing parameters were investigated: the addition of locust bean gum (LBG) at different concentrations (0, 0.5, 1, 1.5, 2, and 2.5%) and printing temperature (30, 40, 60, and 80 °C). Rheological results from a controlled-stress rheometer indicated that gels derived from G. corneum and G. gracilis exhibited a lower gel strength (lower G′ and G″) and excessive material spreading during deposition (lower viscosity) than C. crispus. Thus, G′ was around 5 and 70 times higher for C. crispus gels than for G. corneum and G. gracilis, respectively. When increasing LBG concentration (0.5 to 2.5% w/w) and lowering the printing temperature (80 to 30 °C), an enhanced gel matrix definition for G. corneum and G. gracilis gels was found. In contrast, gels from C. crispus demonstrated greater stability and were less influenced by these parameters, showcasing the potential of the seaweed to develop sustainable clean label food g

Inks based on soybean protein isolate (SPI) were developed and their formulations were optimized as a function of the ink heat treatment and the content of other biopolymers to assess the effects of protein–polysaccharides and protein–protein interactions. First, the rheological behavior of the inks was analyzed in relation to the polyvinyl alcohol (PVA) concentration employed (20, 25, and 30 wt%) and, as a result of the analysis, the ink with 25 wt% PVA was selected. Additionally, sodium alginate (SA) and gelatin (GEL) were added to the formulations to improve the viscoelastic properties of the inks and the effect of the SA or GEL concentrations (1, 2, and 3 wt%) was studied. All inks showed shear thinning behavior and self-supporting abilities. Among all the 3D printed scaffolds, those with higher SA (3 wt%) or GEL (2 and 3 wt%) content showed higher shape fidelity and were selected for further characterization. Texture profile analysis demonstrated that the scaffolds prepared with previously heat-treated inks containing 3 wt% GEL showed the highest strength. Additionally, these scaffolds showed a higher water-uptake capacity profile.

Corona treatment (CT), a surface treatment widely used in the plastic industry, can be used to alter the properties of cassava starch. In the present work, CT was performed on dry granular starch (DS), water-suspended humid granular starch (HS), and gelatinized starch (GS). Different properties and structural characteristics of treated starches were studied. A lowering in pH was generally observed after CT and the rheological properties depended on the starch presentation. A reinforcement of DS and HS samples after CT was deduced from higher viscosity values in flow assays and viscoelastic moduli, but weak gels were obtained when CT was applied to GS. Changes in the A-type polymorphic structure, as well as a drop in relative crystallinity, were produced by CT for DS and HS. Additionally, changes in O-H and C-O-C FTIR bands were observed. Therefore, CT can be applied for starch modification, producing predominantly cross-linking in the DS and depolymerization in the HS. Casting films made from the modified DS showed higher tensile strength and lower hydrophilicity, solubility, water absorption capacity, and water vapor permeability. Thus, the DS cross-linking induced by CT improved mechanical characteristics and hydrophobicity in edible films, which can be better used as packaging materials.

The present study explored the utilization of Rugulopteryx okamurae (RO), an invasive brown seaweed, as a renewable raw material for plastic materials based on biopolymer blends. The goal of this study was to improve the previously observed poor mechanical properties of materials based on single biopolymer RO. To enhance these properties, two polymers with distinct hydrophobicities were incorporated into the formulation of different blends: hydrophobic polycaprolactone (PCL) and hydrophilic acylated soy protein isolate (SPIa). SPIa was derived from soy protein through a chemical modification process, introducing hydrophilic carboxyl groups. The addition of PCL significantly strengthened the blend, increasing the storage modulus (E′1 Hz) from ~ 110 to ~ 250 MPa. Conversely, SPIa incorporation resulted in softening, with E′ values around 40 MPa. Both additives enhanced deformability proportionally to their concentrations, with SPIa exhibiting notably higher deformability, reaching a maximum deformation of ~ 23% for a RO/SPIa ratio of 25/75. In summary, the study demonstrates the feasibility of producing environmentally friendly blend materials based on RO, tailored for specific applications by incorporating suitable additives into the formulation. Therefore, PCL is recommended for applications susceptible to moisture effects, such as packaging, while SPIa is suggested for highly absorbent applications such as personal care or horticulture.

Keratin is a largely available protein that can be obtained from the ca. 3 million tons of feathers that the European poultry industry produces as a side-stream. Here, the functionalization of keratin from poultry feathers was evaluated using a one- versus two-stage process using two functionalization agents (succinic anhydride-SA and ethylene dianhydride-EDTAD). The functionalization resulted in the keratin having improved liquid swelling capacities, reaching up to 400%, 300%, and 85% increase in water, saline, and blood, respectively, compared to non-functionalized keratin. The highest swelling was obtained for samples functionalized with EDTAD (one-stage process), while the highest saline uptake was noted for samples processed with 25 wt% SA (two-stage process). Swelling kinetics modeling indicated that the water uptake by the functionalized samples takes place in two steps, and the EDTAD samples showed the highest diffusivity. It is demonstrated that the one-stage functionalization of keratin utilizing EDTAD results in better performance than two-stages, which allows for resource-saving and, thereby, protecting the environment. The results show some potential for the keratin to be utilized as liquid absorbent materials in water, saline, and blood uptake applications. Using keratin from side-streams is an advantage from a sustainability perspective over biomacromolecules that need to be extracted from virgin biomass.

Biorefinery was used to transform two organic wastes, i.e. urban park & garden green waste and porcine plasma (PPP), into raw materials for biocomposite production. The effect of the nature, size and content of the filler on the final performance of biocomposites was assessed. Two fractions stemming from an urban park and garden green waste, i.e. a representative fraction of the total waste (RF) and a branches-rich fraction (B), were considered as fillers of a PPP bioplastic. PPP-RF/B biocomposites were obtained by compression-moulding and then characterised by tensile tests, dynamic mechanical analysis, water uptake, and water vapour permeability. Using a filler size around 28 µm at 30 wt%, the Young’s Modulus of samples including B fraction was double the value of that including RF, due to the presence of grass in the overall urban waste. Moreover, a greater strengthening was perceived when using larger particle sizes (around 140 µm) of the B fraction, highlighting the importance of the grinding stage. The loss tangent evolution with temperature from dynamic mechanical tests denoted an antiplasticizing effect of the urban biowastes, which should be considered in future applications as a certain exudation degree would be expected. Regarding barrier properties, water permeability increased at higher filler contents (i.e., 30 wt%), while oxygen permeability decreased. Generally, composites from plasma and urban biowaste could be considered in future applications (e.g., packaging), as they showed great reinforcement and stability during water immersion, apart from a darker tonality and decreased oxygen permeability.

The polymer industry was boosted in the middle of the twentieth century when industrial production was made feasible. Nowadays, it is really difficult to find many everyday objects that are not made of plastic or contain plastic parts. Thus, polymer science and technology is an essential area in the materials engineering curriculum, where traditional (e.g., extrusion) and novel (e.g., 3D-printing) processing techniques can be discussed. Two pedagogical strategies were used in the present study. In the theoretical classes, a simple model based on an everyday object (i.e., shoelaces) was used as a demonstration of the structure of polymers, while a questionnaire carried out twice was performed in seminars oriented to the resolution of case studies. ICTs were used in both sessions (i.e., Instagram and Office Excel) to assess the learning process. The students determined that this approach resulted interesting for them, which in the end increased their motivation. Both strategies were successful, as denoted by the results of this academic year compared to the previous ones. This indicates that this innovative activity is a model validated by most students, increasing the development of their competencies and their motivation., La industria de los polímeros se impulsó a mediados del siglo XX cuando se viabilizó la producción industrial. Hoy en día, es realmente difícil encontrar muchos objetos cotidianos que no estén hechos de plástico o contengan piezas de plástico. Por lo tanto, la ciencia y tecnología de polímeros es un área esencial en el plan de estudios de ingeniería de materiales, donde se pueden discutir técnicas de procesamiento tradicionales (p. ej., extrusión) y novedosas (p. ej., impresión 3D). En el presente estudio se utilizaron dos estrategias pedagógicas. En las clases teóricas se utilizó un modelo simple basado en un objeto cotidiano (i.e., cordones de zapatos) como demostración de la estructura de los polímeros, mientras que en los seminarios orientados a la resolución de casos prácticos se realizó un cuestionario realizado en dos ocasiones. En ambas sesiones se utilizaron las TIC (es decir, Instagram y Office Excel) para evaluar el proceso de aprendizaje. Los estudiantes determinaron que este enfoque les resultó interesante, lo que al final aumentó su motivación. Ambas estrategias fueron exitosas, como lo denotan los resultados de este año académico en comparación con los anteriores. Esto indica que esta actividad innovadora es un modelo validado por la mayoría de los estudiantes, aumentando el desarrollo de sus competencias y su motivación., La indústria del polímer es va impulsar a mitjans del segle XX quan es va fer factible la producció industrial. Avui en dia és molt difícil trobar molts objectes quotidians que no siguin de plàstic o que contenen peces de plàstic. Així, la ciència i la tecnologia dels polímers són una àrea essencial en el currículum d'enginyeria de materials, on es poden discutir tècniques de processament tradicionals (per exemple, extrusió) i noves (per exemple, impressió 3D). En el present estudi s'han utilitzat dues estratègies pedagògiques. A les classes teòriques es va utilitzar un model senzill basat en un objecte quotidià (és a dir, cordons de les sabates) com a demostració de l'estructura dels polímers, mentre que es va realitzar un qüestionari realitzat dues vegades en seminaris orientats a la resolució de casos pràctics. Les TIC es van utilitzar en ambdues sessions (és a dir, Instagram i Office Excel) per avaluar el procés d'aprenentatge. Els alumnes van determinar que aquest plantejament els resultava interessant, fet que al final va augmentar la seva motivació. Ambdues estratègies van tenir èxit, tal com demostren els resultats d'aquest curs acadèmic en comparació amb els anteriors. Això indica que aquesta activitat innovadora és un model validat per la majoria dels alumnes, augmentant el desenvolupament de les seves competències i la seva motivació.

The expansion of food production has a large environmental impact in many ways. More specifically, 30–40% of total food production is lost as wastes and/or by-products before it reaches the market. In this sense, blood is an inevitable by-product in the meat industry that typically consists of 3–5% of the total weight of the animal. The dry organic matter present in blood is mostly protein, which can be employed more efficiently as raw material in the development of biodegradable materials. In the present manuscript, the blood collected after slaughtering of Iberian pigs was centrifuged and the upper (i.e., plasma) and bottom (i.e., red cells) layers were separated. Three freeze-dried fractions were characterized and evaluated on terms of their potential in the field of bioplastics: whole blood, plasma and bottom layer. Albumin was detected clearly in the plasma fraction, while globulins in red cells. After their characterization samples were mixed thoroughly with glycerol and injection molded at 120 °C. Special applications may be proposed for every fraction (i.e., whole blood, plasma or red cells), as the materials displayed different properties depending on the raw material employed. Thus, plasma resulted in materials with a greater deformability and swelling capacity during immersion, resulting in superabsorbent materials when processed at milder conditions (80 °C).

The growing concern about reducing carbon footprint has led to the progressive replacement of traditional polymeric materials by natural-based biodegradable materials. However, materials from natural sources (i.e., plants) typically possess poorer mechanical properties when compared to conventional plastics. To counterbalance this, they need to be adequately formulated and processed to eventually meet the standards for certain applications. Zein is the major storage protein from corn and can be obtained as a by-product from the corn-oil industry. It is an excellent candidate for producing green materials due to its stability, biodegradability, renewability, and suitable mechanical and technical-functional properties. In the present work, zein was blended with a plasticizer (i.e., glycerol) at three different zein/glycerol ratios (75/25, 70/30, and 65/25) and then injection moulded at three different processing temperatures (120, 150, and 190 °C). The properties of both blends and bioplastics were evaluated using dynamic mechanical analysis (DMA), tensile tests, and water absorption capacity (WUC). The properties–structure interrelation was assessed through a scanning electron microscope. Generally, a higher zein content and processing temperature led to a certain reinforcement of the samples. Moreover, all bioplastics displayed a thermoplastic behaviour finally melting at temperatures around 80 °C. The lack of massive crosslinking enabled this melting, which finally could be used to confirm the ability of zein based materials to be recycled, while maintaining their properties. The recyclability of thermoplastic zein materials widens the scope of their application, especially considering its biodegradability.

Desmodesmus sp. microalgae previously employed in wastewater management was reused as a raw material for producing green nanofibrous membranes through electrospinning. The reduction of biowastes as well as the replacement of common non-degradable plastics would benefit the process sustainability. In this work, different amounts of microalgae (1.25%, 2.5% and 5% wt) were dispersed in an acetic acid/water solution (80/20) and then electrospun at 0.3 mL/h, 25 kV. The presence of acetate cellulose (17%) was required to obtain nanofibres since the microalgae solutions were not sufficiently viscous for electrospinning processing. For the first time, the effect of ultrasound (50 and 125 kWh/kg), and ozone (9 mg/kg) on microalgae before the electrospinning process was evaluated. Ultrasound prompted cell rupture, which allowed both a greater release and higher exposure of the protein, which eventually enabled the formation of nanofibers from the microalgae waste. However, when the intensity of ultrasounds increased from 50 to 125 kWh/kg, a higher presence of aggregates and defects in the fibres could be observed, probably due to protein aggregation. Thus, nanofibrous mats with c.a. 50 nm fibre diameter were obtained when ultrasound pre-treatment at 50 kWh/kg was applied. Protein unfolding was also inferred from the rheological measurements, as higher viscosity values were obtained (∼ 4.1 Vs. 2.5 Pa·s for 50 and 125 kWh/kg ultrasounds, respectively). The present work highlights the potential that Desmodesmus sp. microalgae have in the production of green electrospun mats, still quite unexplored. These bio-based mats possess great potential in different applications that can range from filtering to scaffolds.

The development of plastic materials based on cassava reduces the dependence on non-biodegradable petroplastics, and enhances the sustainability of the cassava value chain. In this sense, cassava starch (CS) is used as a reinforcer of biocomposites that also contain brown seaweed Rugulopteryx okamurae (RO). RO is an invasive species whose accumulation poses a strong environmental burden in the strait of Gibraltar. Because it can be used as a biopolymer, its use in the plastics industry would promote a healthy ecosystem. Thus, RO/CS mixtures with different RO/CS ratios (from 100/0 to 30/70) were processed through injection moulding at 140 °C. The thermal properties of plastic samples have been analysed through calorimetric, thermogravimetric and rheological techniques. Moreover, the mechanical properties, hydrophilicity, and microstructure of samples have also been studied. Thus, biopolymer degradation of the composites seems to happen at 213–303 °C, as revealed by thermal gravimetric analysis (TGA) of the samples, whereas an exothermic peak observed in DSC at 350–500 °C would be related to the degradation of organic compounds in anaerobic conditions. Rheological tests evidenced a softening of the RO/CS biocomposites when CS content increased in the formulation, so that elastic moduli dropped from 23.72 MPa in the 70/30 to 5.69 MPa for 30/70. However, RO/CS biocomposites became more resistant and deformable as CS content increased: maximum stress and strain at break increased from 78.2 kPa and 0.14% (70/30 system) to 580 kPa and 25.2% (30/70), respectively. Finally, no important differences were observed in their water uptake capacities or microstructures when increasing CS ratio in the mixture. As cassava starch can be extracted from agro-industrial wastes (i.e., cassava peel and bagasse), its use in biocomposites could be of great use for a more sustainable approach for plastic materials.

This manuscript focuses on the production of polymeric matrices enriched in minerals and antioxidant compounds. The biopolymers employed are obtained from different by-products of the agro-food industry (porcine plasma protein, pea protein concentrate and soy protein isolate), which helps to revalorize them. Two different manufacturing techniques are employed to produce these matrices: 3D-printing and injection molding. Bioactivity was enhanced through immersion of the samples in magnesium glutamate and iron lactate solutions. To incorporate these minerals and bioactive compounds into the matrices, two additional stages are required: (1) an immersion stage in a mineral/bioactive containing solution, which allows simultaneous removal of the glycerol employed as plasticizer and entrapment of the minerals and bioactive compounds; and (2) a subsequent freeze-drying stage. Matrices produced through these manufacturing processes were assessed through water uptake capacity, mineral analysis, bioactivity and color measurements. The studied matrices have great potential in the food industry, as the threshold for claiming a significant mineral content was reached after the immersion stage. The presence of bioactive compounds could avoid the degradation of these matrices when food processing includes stages at relatively high temperatures.

The production of green plastic materials from defatted silkworm meal (SW) through a scalable technique (e.g., injection moulding) would permit the revalorization of a by-product of the textile industry. The textile by-product contains an estimable protein content (~50%) which can justify its applicability in the field of eco-materials. Thus, SW-based materials have been processed and characterized, sometimes requiring the addition of another biodegradable polymer, such as polycaprolactone (PCL), in the formulation. Thermomechanical, tensile and water uptake properties have been assessed at different PCL contents (from 0 to 20%). The viscoelasticity of the plastic composites when heated was greatly affected by the melting point of PCL, which also led generally to an increase in their extensibility and resistance. However, this effect of PCL was diminished when composites were processed at higher moulding temperatures. As PCL possesses a hydrophobic character, a decrease in the water uptake was generally detected as PCL content increased, which could also be related to the lower plasticizer content in the formulation. Silkworm meal is an adequate ingredient to consider in the production of green plastic materials that would eventually add value to a main by-product of the sericulture industry.

The seaweed Rugulopteryx okamurae, from the Pacific Ocean, is considered an invasive species in the Mediterranean Sea. In this work, the use of this seaweed is proposed for the development of bio-based plastic materials (bioplastics) as a possible solution to the pollution produced by the plastic industry. The raw seaweed Rugulopteryx okamurae was firstly blended with glycerol (ratios: 50/50, 60/40 and 70/30), and subsequently, they were processed by injection molding at a mold temperature of 90, 120 and 150 °C. The rheological properties (frequency sweep tests and temperature ramp tests) were obtained for blends before and after processing by injection molding. The functional properties of the bioplastics were determined by the water uptake capacity (WUC) values and further scanning electron microscopy (SEM). The results obtained indicated that E’ was always greater than E”, which implies a predominantly elastic behavior. The 70/30 ratio presents higher values for both the viscoelastic moduli and tensile properties than the rest of the systems (186.53 ± 22.80 MPa and 2.61 ± 0.51 MPa, respectively). The WUC decreased with the increase in seaweed in the mixture, ranging from 262% for the 50/50 ratio to 181% for the 70/30 ratio. When carrying out the study on molded bioplastic 70/30 at different temperatures, the seaweed content did not exert a remarkable influence on the final properties of the bioplastics obtained. Thus, this invasive species could be used as raw material for the manufacture of environmentally friendly materials processed by injection molding, with several applications such as food packaging, control–release, etc.

La asignatura Materiales Poliméricos se imparte dentro del Grado de Ingeniería de Materiales de la Universidad de Sevilla, siendo recibida también por alumnos de doble grado de Ingeniería de Materiales y Física o Química. La diferente formación de partida de los tres grupos que asisten a la misma aula a recibir la docencia de la asignatura debe ser considerada en el diseño del programa de la asignatura para evitar dificultades en la formación de un único grupo interdisciplinar. El modelo didáctico empleado ha sido una explicación teórica inicial argumentada con conocimientos ya adquiridos en temas anteriores, seguido de un nuevo problema (i.e., lectura o vídeo) tras el cual se aplicó una actividad de contraste en la pizarra. Se finalizó con una explicación teórica del contenido planteado en el problema propuesto. La participación del alumnado resultó de gran utilidad, interaccionando entre ellos, contrastando ideas y explicándose conceptos entre sí, basados en conocimientos previos. Los resultados del aprendizaje se consideran positivos, al despertar la motivación de los y las alumnas y subir un amplio porcentaje en la escalera de aprendizaje., Polymeric Materials is a class that is taught in the Degree in Materials Engineering at the University of Seville and is also received by students enrolled in the double degree in Materials Engineering and Physics or Chemistry. The different training of the three groups of students that attend the same classroom must be addressed in the design of the program to avoid difficulties in the training of a unique interdisciplinary group. The didactic model used has been based on an initial theoretical explanation based on knowledge already acquired in previous topics, followed by a new problem (i.e., reading or video) after which a contrast activity was applied using the blackboard. It ended with a theoretical explanation of the content raised in the proposed problem. Student participation was high and useful, as they interacted with each other, contrasting ideas and explaining concepts to each other. Learning outcomes are considered positive, by awakening the students’ motivation and climbing a large percentage of the learning ladder.

Society demands that new strategies for learning processes put a greater focus on the students. Thus, new methods must be implemented in higher education studies, leaving guided learning, which is evaluated at the end of the course. The high percentage of abandonment of university studies calls for the implementation of teaching systems in which students are the main actors of the learning processes, under the guidance of the faculty. Moreover, a continuous assessment of students would help to increase student motivation by the continuous feedback of their effort as the course is underway. This work collects the results of different experiences carried out in three different degrees in the University of Seville (Mechanical Engineering, Chemistry and Materials Engineering). These experiences follow a methodology based on case studies, which finally motivated students in every course analysed and promoted the obtainment of higher marks., Cada vez más se exige que las nuevas estrategias para los procesos de aprendizaje pongan un mayor enfoque en los estudiantes. Así, se deben implementar nuevos métodos en los estudios de educación superior que empleen alternativas a la evaluación final. Por otra parte, el alto porcentaje de abandono de los estudios universitarios exige la implementación de sistemas de enseñanza en los que los estudiantes sean los principales actores de los procesos de aprendizaje, donde el profesor actúe de guía. Además, una evaluación continua de los estudiantes ayudaría a aumentar la motivación de los mismos mediante la retroalimentación continua de su esfuerzo a medida que avanza el curso. Este trabajo recoge los resultados de diferentes experiencias llevadas a cabo en tres Grados de la Universidad de Sevilla (Ingeniería Mecánica, Química e Ingeniería de Materiales). Estas experiencias siguen una metodología basada en estudios de casos, que finalmente motivaron a los estudiantes en los cursos donde se aplicó, donde además condujo a mejores calificaciones., Cada vegada més s'exigeix que les noves estratègies per als processos d'aprenentatge posin un enfocament més gran en els estudiants. Així, s'han d'implementar nous mètodes als estudis d'educació superior que facin servir alternatives a l'avaluació final. D'altra banda, l'alt percentatge d'abandonament dels estudis universitaris exigeix la implementació de sistemes d'ensenyament en què els estudiants siguin els actors principals dels processos d'aprenentatge, on el professor actuï de guia. A més, una avaluació continuada dels estudiants ajudaria a augmentar la motivació dels mateixos mitjançant la retroalimentació contínua del seu esforç a mesura que avança el curs. Aquest treball recull els resultats de diferents experiències dutes a terme a tres Graus de la Universitat de Sevilla (Enginyeria Mecànica, Química i Enginyeria de Materials). Aquestes experiències segueixen una metodologia basada en estudis de casos, que finalment van motivar els estudiants als cursos on es va aplicar, on a més va conduir a millors qualificacions.

The replacement of common acrylic derivatives by biodegradable materials in the formu lation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materi als based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.

A great amount of biowastes, comprising byproducts and biomass wastes, is originated yearly from the agri-food industry. These biowastes are commonly rich in proteins and polysaccharides and are mainly discarded or used for animal feeding. As regulations aim to shift from a fossil-based to a bio-based circular economy model, biowastes are also being employed for producing bio-based materials. This may involve their use in high-value applications and therefore a remarkable revalorization of those resources. The present review summarizes the main sources of protein from biowastes and co-products of the agri-food industry (i.e., wheat gluten, potato, zein, soy, rapeseed, sunflower, protein, casein, whey, blood, gelatin, collagen, keratin, and algae protein concentrates), assessing the bioplastic application (i.e., food packaging and coating, controlled release of active agents, absorbent and superabsorbent materials, agriculture, and scaffolds) for which they have been more extensively produced. The most common wet and dry processes to produce protein-based materials are also described (i.e., compression molding, injection molding, extrusion, 3D-printing, casting, and electrospinning), as well as the main characterization techniques (i.e., mechanical and rheological properties, tensile strength tests, rheological tests, thermal characterization, and optical properties). In this sense, the strategy of producing materials from biowastes to be used in agricultural applications, which converge with the zero-waste approach, seems to be remarkably attractive from a sustainability prospect (including environmental, economic, and social angles). This approach allows envisioning a reduction of some of the impacts along the product life cycle, contributing to tackling the transition toward a circular economy.

Composite materials based on proteins and carbohydrates normally offer improved water solubility, biodegradability, and biocompatibility, which make them attractive for a wide range of applications. Soy protein isolate (SPI) has shown superabsorbent properties that are useful in fields such as agriculture. Alginate salts (ALG) are linear anionic polysaccharides obtained at a low cost from brown algae, displaying a good enough biocompatibility to be considered for medical applications. As alginates are quite hydrophilic, the exchange of ions from guluronic acid present in its molecular structure with divalent cations, particularly Ca2+, may induce its gelation, which would inhibit its solubilization in water. Both biopolymers SPI and ALG were used to produce composites through injection moulding using glycerol (Gly) as a plasticizer. Different biopolymer/plasticizer ratios were employed, and the SPI/ALG ratio within the biopolymer fraction was also varied. Furthermore, composites were immersed in different CaCl2 solutions to inhibit the amount of soluble matter loss and to enhance the mechanical properties of the resulting porous matrices. The main goal of the present work was the development and characterization of green porous matrices with inhibited solubility thanks to the gelation of alginate.

El presente trabajo tiene como objetivo el análisis del efecto que tiene el empleo de aplicaciones informáticas de uso común en estudiantes de Máster, determinando cuáles pueden adaptarse fácilmente a clases presenciales en un entorno único como es el actual, donde la enseñanza ha tenido que adaptarse forzosamente, debido a las excepcionales circunstancias producidas por la crisis sanitaria del COVID-19. La hipótesis de partida es que el interés y motivación de los estudiantes puede incrementarse haciendo uso de herramientas informáticas que resultan cotidianas para ellos. Por otra parte, los alumnos están habituados al estímulo que éstas promueven, requiriendo en multitud de ocasiones un estímulo similar para para mantener el nivel de atención. Incluir estas aplicaciones en la docencia, aumentará la motivación de los mismos, y con ella el interés y el grado de satisfacción con la asignatura. Este estudio se ha llevado a cabo entre los estudiantes de la asignatura “Instalaciones Ambientales en la Industria de Combustible y Gases Técnicos en la Industria” del Máster Universitario en Diseño e Ingeniería de Productos e Instalaciones Industriales en Entornos PLM y BIM, impartido en la Escuela Politécnica Superior de la Universidad de Sevilla. La metodología propuesta ha tenido por objeto promover el seguimiento de la asignatura por parte de los estudiantes, aumentando la motivación y el interés de los mismos hacia la asignatura, a la par que se han facilitado las herramientas disponibles para que aquellos alumnos que por circunstancias justificadas no hayan podido asistir presencialmente a clase, pudieran hacerlo de manera virtual, o realizar el seguimiento de la asignatura con el material disponible en la enseñanza virtual. En el presente estudio, la plataforma utilizada por la Universidad de Sevilla en el contexto virtual ha sido Blackboard (Blackboard Inc., EE.UU.). Se parte de la base de que como consideración general que los alumnos se sienten atraídos por el uso d

El presente estudio se ha realizado en la asignatura Ingeniería Química perteneciente al tercer curso del Grado de Química impartido en la Universidad de Sevilla (España). La asignatura “Ingeniería Química” es una asignatura obligatoria de 9 créditos ECTS. Se trata de la primera asignatura dentro del área de ingeniería química impartida en el grado de química. Posteriormente, el alumno deberá superar otras asignaturas de la misma área de conocimiento, como la asignatura obligatoria “Redacción y Ejecución de Proyectos”, o la asignatura optativa “Química Industrial”, ambas de cuarto curso. Se plantea aplicar la metodología de Aprendizaje Colaborativo con los siguientes objetivos específicos: ‒ Fomentar la comprensión de conceptos relacionados con la ingeniería a partir de la resolución de casos prácticos y de balances de materia y energía ‒ Uso de Aprendizaje Colaborativo mediante la programación de tutorías grupales a distancia ‒ Evaluación de la metodología sincrónica y asincrónica en las tutorías grupales.

La inulina es un carbohidrato no digerible que está presente en muchos vegetales, frutas y cereales. En la actualidad, se extrae industrialmente de la raíz de la achicoria y se utiliza ampliamente como ingrediente en alimentos funcionales (e.g. productos lácteos). En este trabajo de investigación se estudió el comportamiento reológico de geles de inulina, a diferentes contenidos del polisacárido (15, 20, 25 %) y sales de calcio (lactato o cloruro, a 0, 2,5 o 5 %). Se observó, de forma general un aumento en los módulos de cizalla de almacenamiento y viscoso (G’ y G’’, respectivamente) al incrementarse la concentración de inulina o la presencia de cloruro de calcio en la solución original a partir de la que se forma el gel. Por otra parte, ambos módulos generalmente disminuyeron con la presencia de lactato de calcio. La adición de cloruro de calcio, por tanto, permitirá la formación de un gel reforzado, con el beneficio adicional de la presencia de calcio, lo cual lo convierte en un buen punto de partida para la producción de alimentos funcionales., Inulin is a non-digestible oligosaccharide that is pres-ent in many vegetables, fruits, and cereals. Nowadays, it is industrially extracted from chicory root and is widely used as an ingredient in functional foods (e.g. dairy products). In this research work, the rheological behavior of inulin gels was studied at different inulin (15, 20, 25 %) and calcium salts contents (lactate or chloride, at 0, 2.5 or 5 %). In general, an increase in the storage and viscous shear moduli (G ‘and G’ ‘, respec-tively) was observed when increasing inulin content or when Calcium chloride was present in the original solution that led to the formation of the gel. On the other hand, both viscoelastic moduli generally decreased in the presence of Calcium lactate. The addition of Calcium chloride, therefore, allows the formation of a reinforced gel with the additional benefit of including Calcium in the formulation, which would be a good starting point for the production of functional foods., La inulina és un carbohidrat no digerible que està present en molts vegetals, fruites i cereals. En l’actu-alitat, s’extreu industrialment de l’arrel de la xicoira i s’utilitza àmpliament com a ingredient en aliments funcionals (p.e. productes làctics). En aquest treball de investigació es va estudiar el comportament reològic de gels de inulina, a diferents continguts del polisacàrid (15, 20, 25%) i sals de calci (lactat o clorur, a 0, 2,5 o 5%). Es va observar, de forma general un augment en els mòduls de cisalla d’emmagatzematge i viscós (G’ i G’’, respectivament) a l’incrementar-se la concentració de inulina o la presència de clorur de calci en la solució original a partir de la qual es forma el gel. D’altra ban-da, tots dos mòduls generalment van disminuir amb la presència de lactat de calci. L’addició de clorur de calci, per tant, permetrà la formació d’un gel reforçat, amb el benefici addicional de la presència de calci, la qual cosa el converteix en un bon punt de partida per a la producció d’aliments funcionals.

En este trabajo se estudia la influencia del pH en bioplásticos de plasma sanguíneo, en los que ya ha sido demostrada su capacidad superabsorbente. Una modificación en el pH tiene una fuerte influencia en el comportamiento de las proteínas y, por tanto, en las propiedades de los bioplásticos que se obtienen a partir de ellas. Así, el cambio más notable en las propiedades mecánicas y capacidad de absorción se observa al acidificar el pH.

Inulin is a prebiotic polysaccharide that is being increasingly used in food emulsions as fat replacer, due to its thickening effect. In the present work, oil in water (O/W) emulsions (5/95) have been prepared by means of a pressure homogenizer, using β-lactoglobulin as an emulsifier (0.5 %), and varying the polysaccharide content up to 10 %. The zeta potential measurements suggest that there are no significant protein-polysaccharide interactions in the continuous phase. An increase in viscoelastic properties and viscosity of these pseudoplastic systems is observed as inulin content increases. Although inulin has no surface activity, its presence seems to favor protein adsorption kinetics at the interface. Likewise, the distribution of droplet sizes study for emulsions throughout the storage time points out how bimodal distributions obtained remain constant, indicating their stability, which is reinforced by backscattering results. These prebiotic emulsions may enjoy a great demand by the food industry., La inulina es un polisacárido prebiótico que se utiliza cada vez más en emulsiones alimentarias como sustituyente de grasa, al tener un efecto espesante sobre las mismas. En el presente trabajo, se han preparado emulsiones aceite/agua (5/95) mediante un homogeneizador de presión, utilizando b-lactoglobulina como emulsionante a una concentración fija de 0,5 % (p/p), y variando el contenido en polisacárido desde 0 al 10 % (p/p). Las medidas de popotencial zeta sugieren que no existen interacciones importantes entre la proteína y el polisacárido en la fase continua, al tiempo que se observa un aumento de las propiedades viscoelásticas y viscosidad de estos sistemas pseudopláticos. Aunque la inulina no presenta actividad superficial, su presencia parece favorecer la cinética de adsorción de la proteína en la interfase. Asimismo, el estudio de la distribución de tamaños de gota de las emulsiones a lo largo del tiempo de almacenamiento permite observar cómo las distribuciones bimodales obtenidas permanecen constantes, indicando la estabilidad de las mismas. Esto queda reforzado por los resultados obtenidos por medio de un analizador óptico de emulsiones con detectores de luz transmitida y retrodispersa. Emulsiones con ingredientes prebióticos como las estudiadas tiene un gran potencial en la industria alimentaria., La inulina és un polisacàrid prebiòtic que s’utilitza cada vegada més en emulsions alimentàries com substituent del greix, en tenir un efecte espessidor sobre les mateixes. En el present treball, s’han preparat emulsions oli / aigua (5/95) mitjançant un homogeneïtzador de pressió, utilitzant β-lactoglobulina com emulsionant a una concentració fixa de 0,5% (p/p), i variant el contingut en polisacàrid des de 0 al 10% (p/p). Les mesures de potencial zeta suggereixen que no hi ha interaccions importants entre la proteïna i el polisacàrid a la fase contínua, alhora que s’observa un augment de les propietats viscoelàstiques i de la viscositat d’aquests sistemes pseudoplàstics. Tot i que la inulina no presenta activitat superficial, la seva presència sembla afavorir la cinètica d’adsorció de la proteïna a la interfase. Així mateix, l’estudi de la distribució de mides de gota de les emulsions al llarg del temps d’emmagatzematge permet observar com les distribucions bimodals obtingudes romanen constants, indicant l’estabilitat de les mateixes. Això queda reforçat pels resultats obtinguts per mitjà d’un analitzador òptic de emulsions amb detectors de llum transmesa i retrodispersa. Emulsions amb ingredients prebiòtics com les estudiades tenen un gran potencial en la indústria alimentària.

Superabsorbent materials are used in a wide range of products (e.g. personal care, controlled-release of nutrients in agriculture). The present study pretends the development of biodegradable materials from a natural source, a soy protein isolate, which eventually would help to diminish the environmental issues associated to the use of common synthetic materials. Moreover, the present work focuses on the modulation of the water uptake exclusively through the modification of the parameters of the thermal processes carried out during the development of those materials. Firstly, the protein isolate is blended with the plasticizer (glycerol) in a 1/1 ratio. Then, the homogeneous blend is injected using different mould temperatures and, subsequently, the bioplastics obtained are submitted to a dehydrothermal treatment (tdeshid) consisting on the storage of the samples at 50 ºC for a certain time (tdeshid). When the mould temperature is 70 ºC, superabsorbent materials are always obtained at tdeshid, shorter than 12 h. Conversely, viscoelastic properties increase as DHT treatment is longer, reducing the swelling that takes place during water absorption, and resulting more compact matrices. Thus, the present study proves how thermal processing modulation can solely determine the superabsorbent ability of soy protein-based biodegradable materials., Los materiales superabsorbentes son aplicables en campos tan diversos como productos de higiene personal o liberación controlada de nutrientes en agricultura. El presente estudio pretende el desarrollo de materiales biodegradables a partir de una materia prima natural, un aislado de proteína de soja, cuya aplicación supondría una disminución en el uso de materiales sintéticos, repercutiendo beneficiosamente en el medio ambiente; y la modulación de su capacidad de absorción de agua, que se modificará exclusivamente variando las condiciones de los procesos térmicos a los que son sometidas durante su obtención. En primer lugar, el aislado se mezcla con glicerina (plastificante)en una proporción 1/1, para después inyectar la masa homogénea utilizando diferentes temperaturas de moldeo (Tmold). Posteriormente, son sometidas a un tratamiento deshidrotérmico. o almacenamiento a 50ºC, durante cierto periodo de tiempo (tdeshid). Cuando la Tmold utilizada es 70ºC, se obtienen siempre materiales superabsorbentes, cuando el tdeshid seleccionado sea menos de 12h. Por otra parte, las propiedades viscoelásticas aumentan con la duración del tratamiento deshidrotérmico, provocando un menor hinchamiento durante la absorción de agua, resultando matrices menos porosas. Así, el presente estudio permite comprobar cómo modulando exclusivamente las condiciones de procesado pueden conseguirse capacidades superabsorbentes para materiales biodegradables basados en soja.

Porcine blood is a by-product of the meat industry, and it could be considered as a potential raw material in the formulation of biodegradable materials with great water absorption capacity, due to its rich composition in hydrophilic aminoacids. With the aim to evaluate this potential, Porcine Plasma protein (PP) has been mixed with glycerine (GL) as plasticizer, obtaining through injection moulding bioplastic samples eventually assessed. In order to maximize its water uptake capacity, the concentration effect on PP in blend was evaluated (50, 55 and 60 %). All materials obtained, independently of the PP quantity, showed superabsorbent properties, when they were moulded at 60 ºC, using an injection and holding pressure of 500 bar for 150 s. These materials were able to hold around 2000 % its own weight, exceeding the threshold generally established for the absorbent capacity (i.e. 1000 %) of superabsorbent materials. The absence of acrylic ingredients together with the revalorization of an organic by-product would promote the production of this kind of materials as an economic and biodegradable alternative to those superabsorbent products traditionally used., La fracción plasmática de la sangre porcina obtenida como subproducto en la industria cárnica puede ser considerada una potencial materia prima en la formulación de materiales biodegradables con elevada capacidad absorbente, ya que en su composición presenta una gran cantidad de aminoácidos hidrofílicos. Con objeto de evaluar dicho potencial, se ha mezclado convenientemente un concentrado de proteína de plasma porcino (PP, Apropork) con glicerina (GL) como plastificante, obteniéndose posteriormente mediante inyección diferentes materiales bioplásticos. Para maximizar su capacidad absorbente, se ha estudiado el efecto de la concentración de PP en la mezcla (50, 55 y 60 %). Todos los materiales procesados a partir de las mezclas PP/GL en este estudio presentaron capacidades superabsorbentes, con capacidades de absorción de agua superiores a 1.000 %. Así, valores alrededor de 2.000 %, se alcanzaron en las muestras, independientemente del contenido en PP, cuando fueron moldeadas a una temperatura de 60 ºC, con un tiempo de inyección de 150 s y utilizando una presión de 500 bar. La ausencia de derivados acrílicos en su formulación, así como la revalorización que resultaría del subproducto orgánico seleccionado, favorecería el desarrollo de este tipo de materiales como una alternativa económica y biodegradable a los productos superabsorbentes tradicionalmente utilizados., La fracció plasmàtica de la sang porcina obtinguda com a subproducte en la indústria càrnia pot ser considerada una potencial matèria primera en la formulació de materials biodegradables amb elevada capacitat absorbent, ja que en la seva composició presenta una gran quantitat d'aminoàcids hidrofílics. A fi d'avaluar aquest potencial, s'ha barrejat conve 104 | AFINIDAD LXXVI, 586 nientment un concentrat de proteïna de plasma porcí (PP, Apropork) amb glicerina (GL) com a plastificant, obtenint-posteriorment mitjançant injecció diferents materials bioplàstics. Per maximitzar la seva capacitat absorbent, s'ha estudiat l'efecte de la concentració de PP a la barreja (50, 55 i 60%). Tots els materials processats a partir de les mescles PP / GL en aquest estudi van presentar capacitats superabsorbents, amb capacitats d'absorció d'aigua superiors a 1.000%. Així, valors al voltant de 2.000%, es va aconseguir en les mostres, independentment del contingut en PP, quan van ser modelades a una temperatura de 60 ºC, amb un temps d'injecció de 150 s i utilitzant una pressió de 500 bar. L'absència de derivats acrílics en la formulació, així com la revaloració que resultaria del subproducte orgànic seleccionat, afavoriria el desenvolupament d'aquest tipus de materials com una alternativa econòmica i biodegradable als productes superabsorbents tradicionalment utilitzats.

The guided and evaluated learning at the end of the course is a vestige inherited from the old curricula. With the reduction of the number of students, as well as with the implementation of the new curricula, the teaching system has to be changed, turning towards a way in which the student is the main actor and the teacher carries out a continuous feedback (guided process). In the present research it has been shown that the continued work of students, with real problems associated with Engineering, allows the learning process to be carried out with a greater motivation and, therefore, involvement by the students, improving their academic performance, El aprendizaje guiado y evaluado al final del curso es un vestigio heredado de los antiguos planes de estudios. Con la reducción del número de alumnos, así como con la implementación de los nuevos planes de estudio se hace necesario cambiar el sistema de enseñanza, virando hacia un modeo en el que el alumno sea el protagonista y que el profesor lleve a cabo un proceso de retroalimentación (guiado) continuado. En el presente estudio queda demostrado que el trabajo continuo de los alumnos con problemas reales asociados a la Ingeniería permite que el proceso de aprendizaje lleve acarreado una mayor motivación y, por ende, implicación por parte de los estudiantes, mejorando el rendimiento de los mismos.

Inulin is a prebiotic ingredient that is being increasingly used in food formulations as fat replacer. The present manuscript focuses on the formation of gels formed from inulin aqueous dispersions, observing the effect of inulin content, ranging from 25 to 50 wt%, and of the presence of calcium salts (chloride, lactate) at different concentrations up to 5 wt% Gels are observed to be stronger and formed in a shorter time as the polysaccharide content is higher. Both backscattering and rheological techniques can be used to follow the gelation, being able to detect a significant initial setting stage at 25 wt% inulin content. When calcium salts are added, weakening of gels takes place, resulting in lower values of the storage and loss moduli, G′ and G″, respectively, as well as in a reduction of the linear viscoelastic range. Moreover, gelation seems to be retarded on a large scale of time due to the presence of salt. Prebiotic gels containing calcium are of special interest for the development of functional foods, always considering the effect they exert on the rheology when formulating these products.

Recently, bioplastic have generated an increasing interest as an alternative to conventional plastics. For this reason, their manufacture using the traditional techniques used for the production of plastics, such as extrusion, would help transferring bioplastics production to an industrial scale. In this way, the preparation of wheat gluten bioplastics by extrusion was the main objective of this research, modifying their structure by varying the pH value or by incorporating additives (glyoxal or xanthan gum). These bioplastics were characterized by the measurement of their mechanical properties and their water uptake capacity, proving that the modification of bioplastics cause variations in their properties. Thus, extrusion resulted in a greater gluten-plasticizer compatibility compared to compression, as denoted the temperature ramp tests, especially in the presence of additives (ie. Xanthan gum, glyoxal). Moreover, tensile strength was enhanced at pH 9, probably due to bonding promotion at alkaline conditions. These results demonstrate the great potential of these materials for the replacement of conventional plastics.

La industria de los plásticos ha crecido notablemente en los últimos años. Este crecimiento, ligado a la baja biodegradabilidad de estos materiales, ha causado un grave problema medioambiental. La presente investigación pretende la obtención de materiales con alta capacidad de absorción de agua, que sean biodegradables y obtenidos a partir de fuentes renovables. Deberían además poseer propiedades mecánicas adecuadas para constituir una alternativa real a los plásticos sintéticos. Estos bioplásticos son obtenidos mediante un proceso con diferentes etapas: una de mezclado de los componentes para conformar una masa homogénea; y una segunda de inyección en la que, aplicando presión, la masa es introducida en un molde de forma deseada. La capacidad de absorción de agua es afectada por la composición y las condiciones de procesado. El presente documento estudia cómo la temperatura y duración de la etapa de moldeo, además del tratamiento dehidrotérmico, modifican la capacidad de absorción del bioplástico. Los resultados concluyen que la capacidad de absorción de agua aumenta con menores temperaturas y tiempos de moldeo, a la vez que aumenta cuando el tratamiento dehidrotérmico es más corto. Asimismo, los módulos viscoelásticos poseen una tendencia a disminuir cuando la capacidad de absorción de agua en las muestras aumenta., The remarkable growth experienced by the production and demand of the plastic industry during the last few years has resulted in a serious environmental issue associated specially to their low biodegradability. This work is focused on the manufacture of bioplastics with high water absorption capacity, obtained from renewable sources. Bioplastics produced should have adequate mechanical properties to be able to replace eventually synthetic plastics in specific markets. In order to obtain these bioplastics, two steps were carried out: the first one consists of a mixing stage to achieve a homogenous blend that is injection-molded during the second step. The water uptake capacity of these samples is influenced by both the formulation and the processing conditions of the blends. The present study is focused on the evolution of water uptake values when either the molding conditions (temperature and duration) or the length of a post-dehydrothermal treatment are modified. Results indicated an improvement in the water uptake when lower mold temperatures and shorter compaction stages were used. An analogous improvement was observed when the dehydrotermal process was shorter. Mechanical properties usually decreased as the water uptake of samples was improved.

El desarrollo de bioplásticos podría ayudar a combatir el problema medioambiental derivado del uso masivo de plásticos procedentes del petróleo, contribuyendo a la producción de materiales de mayor degradabilidad. Todos los bioplásticos objeto de estudio del presente trabajo poseen una relación proteína/plastificante igual a 60/40. Los bioplásticos se obtuvieron en un proceso que consta de una primera etapa de mezclado, resultando una masa homogénea que fue sometida posteriormente a una segunda etapa de moldeo por inyección. El adecuado control de estas etapas es una parte fundamental en el proceso de elaboración de bioplásticos, por lo que el objetivo principal de este trabajo ha sido explorar la influencia de la velocidad de mezclado sobre las masas y los bioplásticos resultantes. Para ello, se realizó una caracterización de los mismos mediante el estudio de su capacidad de absorción de agua, ensayos mecánicos de tracción, y ensayos reológicos en modo dinámico. Entre los resultados obtenidos, puede destacarse que a bajas velocidades de mezclado resultan masas heterogéneas con variabilidad en sus propiedades., The development of bioplastics could avoid the environmental problem derived from the huge use of petroleum-based plastics and contribute to the production of more degradable materials. In this study, bioplastics have a protein/plasticizer ratio of 60/40 from pea protein and glycerol, respectively. They were manufactured in two stages. Firstly, a mixing stage, in which the resulting dough was use in the second stage, an injection molding. The control of these stages is a fundamental part in the process. The main objective of this work is to explore the influence of the speed of mixing on the dough and bioplastics. The characterization of bioplastics was performed by means of water absorption capacity and rheological dynamic tests. Among the results, it can be highlighted that a heterogeneous dough with variability in their properties appears at low mixing speeds.