A rheological approach to 3D printing of plasma protein based doughs

Characterization of the effects of insoluble soybean polysaccharides on the formation and physicochemical properties of soybean isolate protein gel

The effects of insoluble soybean polysaccharides (ISPS) on the formation and physicochemical properties of soybean protein isolate (SPI) gel were studied. As ISPS concentration increased, SPI suspensions showed reduced surface hydrophobicity and zeta-potential and enhanced thermal stability. However, the zeta-potential increased after gel formation. The ISPS decreased the hardness of the 6 % SPI gel, which could be attributed to the fact that ISPS reduced the elasticity of gel network, making the microstructure loose and porous and behaving as a weak gel; however, for the 10 % SPI gel, the ISPS promoted the increase in hardness and exhibited a weaker negative impact on the textural and microstructural properties of SPI gel. Results revealed that ISPS could react with SPI via non-covalent bonds and embedded into the protein network, weakening or strengthening the structure and texture of SPI gel and this impact is related to the mass ratio between these two biopolymers.

Rice starch, millet flour supplemented with algal biomass for 3D food printing

3D printing has facilitated food production customization, yet there is a lack of exploration into gluten-free cereal materials within this domain. This study investigates the utilization of millet-based 3D printing to produce fortified products incorporating Azolla filliculoides (AF) microalgae. AF contains essential nutrients like carbohydrates, lipids, dietary fiber, and amino acids emphasizing its nutritional significance. Experimental assessments were conducted on dough formulations containing pearl millet flour fortified with AF to standardise rheological and textural characteristics, ensuring precision in 3D printing. Optimal results were observed in formulations with 15 % microalgae incorporation (AF-15 %). Regarding rheology, AF-25 % and AF-15 % formulations exhibited shear-thinning behaviour, with enhanced pseudoplasticity. The texture of 3D printing formulations reflected increased firmness with higher algal biomass, attributed to increased protein and carbohydrate content. Moreover, printing efficiency for gluten-free blends exhibited variability, with occasional errors and increased viscosity in AF-15 % formulations, while AF-25 % formulations proved impractical for printing due to reduced cohesiveness. Color assessments indicated increased pigment saturation with increased algal biomass. Further, mineral analysis demonstrated a significant elevation in the mineral content of the 3D printed products. This affirms the positive impact of Azolla biomass on nutritional and rheological properties in gluten-free 3D printed products.

Rheology and printability of biopolymeric oil-in-water high internal phase Pickering emulsions: a review

Biopolymeric oil-in-water (O/W) high internal phase Pickering emulsions (HIPPEs) due to their unique rheological behaviors of HIPPEs such as shear-thinning property, viscoelasticity, and thixotropic recovery have emerged as highly promising printing inks in the 3D printing process. O/W biopolymer-based HIPPEs are categorized as complex fluids, where rheological parameters are crucial for optimizing printability. However, existing reviews have not fully elucidated the interrelationship between rheology and printability for HIPPEs in enhancing the quality and performance of printed parts. This review delved into the influence factors of the continuous phase (e.g., biopolymer type, concentration, pH, and ionic strength) and the oil phase (e.g., oil type, volume fraction, and encapsulated components) on their rheology, to adjust their rheological behaviors in order to prepare more eligible HIPPEs as printing inks. Moreover, a spectrum of rheology-printability relationships, derived from empirical trends and rigorous analytical models, is examined to provide generalized rheological guidelines for achieving successful printability in O/W biopolymer-based HIPPEs. Furthermore, unique challenges and future perspectives on preparing their complex rheological behaviors suitable for additive manufacturing in O/W biopolymer-based HIPPEs were presented. Leveraging these insights significantly reduces reliance on trial-and-error methods in printing, thereby fostering the robust development of novel O/W biopolymer-based HIPPEs and enhancing the overall quality of printed products.

Development of special nutritional balanced food 3D printing products based on the mixing of animals/plants materials: research progress, applications, and trends

Food 3D printing brings food processing technology into the digital age. This is a vast field that can provide entertainment experience, personalized food and specific nutritional needs. However, the limited availability of suitable food raw materials has restricted the extensive use of 3D food printing processing technique. The search for novel nutritious and healthy food materials that meet the demand for 3D food printing processing technology is core of the sustainable development of this emerging technology. The printing mechanism, precise nutrition, future outlooks and challenges of 3D food printing technology application in hybrid plant and animal food materials are also analyzed.The results demonstrate that selecting suitable animal and plant materials and mixing them into 3D food printing ingredients without adding food additives can result in printable inks, which can also improve the nutritive value and eating quality of 3D food printed products. Sustainability of novel food materials such as animal cell culture meat and microbial protein mixed with conventional food materials to realize 3D printed food can be a potential research direction. Some other issues should also be considered in future research, such as evaluation of the nutritional efficacy of the product, product stability, shelf life, production efficiency and convenience of process operation.

Development of an Operational Map for the 3D Printing of Phytosterol-Enriched Oleogels: Rheological Insights and Applications in Nutraceutical Design

Three-dimensional (3D) printing attracts significant interest in the food industry for its ability to create complex structures and customize nutritional content. Printing materials, or inks, are specially formulated for food or nutraceuticals. These inks must exhibit proper rheological properties to flow smoothly during printing and form stable final structures. This study evaluates the relationship between rheological properties and printability in phytosterol-enriched monoglyceride (MG) oleogel-based inks, intended for nutraceutical applications. Key rheological factors, including gelation temperature (Tg), elastic (G') and viscous (G″) modulus, and viscosity (µ) behavior with shear rate (γ˙), were analyzed for their impact on flow behavior and post-extrusion stability. Furthermore, this study allowed the development of an operation map to predict successful printing based on material µ and Tg. Oleogels (OGs) were prepared with high-oleic sunflower oil (HOSO) and 10 wt% MG, enriched with phytosterols (PSs) at concentrations between 0 and 40 wt%. While higher PS content generally led to an increase in both Tg and µ, the 10 wt% PS mixture exhibited a different behavior, showing lower Tg and µ compared to the 0 wt% and 5 wt% PS mixtures. The optimal PS concentration was identified as 20 wt%, which exhibited optimal properties for 3D printing, with a Tg of 78.37 °C and µ values ranging from 0.013 to 0.032 Pa.s that yielded excellent flowability and adequate G' (3.07 × 106 Pa) at room temperature for self-supporting capability. These characteristics, visualized on the operational map, suggest that 20% PS OGs meet ideal criteria for successful extrusion and layered deposition in 3D printing.

Enhancing Polylactic Acid Properties with Graphene Nanoplatelets and Carbon Black Nanoparticles: A Study of the Electrical and Mechanical Characterization of 3D-Printed and Injection-Molded Samples

This study investigates the enhancement of polylactic acid (PLA) properties through the incorporation of graphene nanoplatelets (GNPs) and carbon black (CB) for applications in 3D printing and injection molding. The research reveals that GNPs and CB improve the electrical conductivity of PLA, although conductivity remains within the insulating range, even with up to 10% wt of nanoadditives. Mechanical characterization shows that nanoparticle addition decreases tensile strength due to stress concentration effects, while dispersants like polyethylene glycol enhance ductility and flexibility. This study compares the properties of materials processed by injection molding and 3D printing, noting that injection molding yields isotropic properties, resulting in better mechanical properties. Thermal analysis indicates that GNPs and CB influence the crystallization behavior of PLA with small changes in the melting behavior. Dynamic Mechanical Thermal Analysis (DMTA) results show how the glass transition temperature and crystallization behavior fluctuate. Overall, the incorporation of nanoadditives into PLA holds potential for enhanced performance in specific applications, though achieving optimal conductivity, mechanical strength, and thermal properties requires careful optimization of nanoparticle type, concentration, and dispersion methods.

Algae-Boosted Chickpea Hummus: Improving Nutrition and Texture with Seaweeds and Microalgae

The global food industry faces a critical challenge in ensuring sustainable practices to meet the demands of a growing population while minimizing environmental impact. At the same time, consumer awareness and the demand for quality products drive innovation and inspire positive changes in the food supply chain. Aiming to create a more sustainable and nutrient-rich alternative, this study is summarized by characterizing the physical and chemical characteristics of algae-enriched chickpea hummus: an innovative approach to popular food products. The algae-enriched hummuses were developed with an incorporation (6% w/w) of Gelidium corneum and Fucus vesiculosus seaweeds and Chlorella vulgaris (hetero and autotrophic) microalgae to reveal their technological potential and evaluate the nutritional and rheological characteristics relative to a control hummus (without algae). From a nutritional perspective, the main results indicated that hummus enriched with microalgae showed an increase in protein content and an improved mineral profile. This was particularly notable for the seaweed F. vesiculosus and the autotrophic microalga C. vulgaris, leading to claims of being a "source of" and "rich in" various minerals. Additionally, the antioxidant activity of hummus containing F. vesiculosus and C. vulgaris increased significantly compared to the control. From a rheological perspective, incorporating algae into the humus strengthened its structure. The microalgae further enhanced the dish's elasticity and firmness, thus improving this chickpea-based dish´s overall texture and quality.

Ultralight aerogels via supramolecular polymerization of a new chiral perfluoropyridine-based sulfonimidamide organogelator

Chiral and enantiopure perfluorinated sulfonimidamides act as low-molecular weight gelators at low critical gelation concentration (<1 mg mL-1) via supramolecular polymerization in nonpolar organic solvents and more heterogenic mixtures, such as biodiesel and oil. Freeze-drying of the organogel leads to ultralight aerogel with extremely low density (1 mg mL-1). The gelation is driven by hydrogen bonding resulting in a helical molecular ordering and unique fibre assemblies as confirmed by scanning electron microscopy, CD spectroscopy, and computational modeling of the supramolecular structure.

Effect of protein-polysaccharide hybrid gelator system on the material properties and 3D extrusion printability of mashed potatoes

Mashed potatoes (MP) are famous as ready-to-eat products due to their excellent taste and texture. Problems such as complex injection occur when MP is used as a 3D printing material. To improve the smoothness of MP loading into a 3D syringe barrel and its 3D extrusion printability, the effects of the protein-polysaccharide hybrid gelator developed with different gelatin-B (GB, 2%, 4%, 6%) and κ-carrageenan (KG, 1%) on the rheology and 3D extrusion printability of MP were studied. The rheological results showed that the MP developed a glass transition temperature by adding the hybrid gelator. Adding 1% KG+6% GB (w/w, dry base) to the hybrid gelator has good shear thinning and self-supporting properties and showed the best geometric accuracy. In the extrusion stage, the yield stress, the consistency index (K), and the flow behavior index (n) of MP were 470.69 Pa, 313.48 Pa·sn, and 0.159, respectively. In the recovery stage, the shear recovery time is 30 s. In the self-supporting stage, the storage modulus and loss modulus are significantly higher than those of other groups and have the strongest mechanical properties. Moreover, water distribution, Fourier transform infrared spectroscopy, X-ray diffraction analysis, and microstructure of printed MP with different hybrid gelators were observed. The addition of hybrid gelators reduced the content of free water in MP. Hybrid gelators did not produce new functional groups in the printed materials and did not change the structure of starch. These results provide new insights for applying protein and polysaccharide hybrid gelators in 3D printing.

Development of Healthy Snacks Incorporating Meal from Tenebrio molitor and Alphitobius diaperinus Using 3D Printing Technology

This study analyzes the nutritional properties of edible insects, specifically Tenebrio molitor and Alphitobius diaperinus, and explores the potential of 3D printing technology to introduce a nutritious and tasty alternative to essential nutrients for Western consumers. An original formulation for the printing of snacks with microalgae was adapted to incorporate edible insects. Concentrations of 10% of edible insects, both isolated and mixed, were incorporated into the developed ink-doughs. Stress and frequency sweeps were performed on the doughs to understand the rheology and the impact on the internal structure to better adapt these materials to the 3D printing process. The nutritional profile of the developed snacks was assessed, revealing a significant amount of protein, enough to claim the snacks as a "source of protein", as well as an increased mineral profile, when compared to the control snack. The antioxidant profile and total phenolic content were equally assessed. Finally, a sensory analysis test was performed, comparing the control snack to three other samples containing 10% T. molitor, 10% A. diaperinus and 5% + 5% of T. molitor and A. diaperinus, respectively, resulting in a preference for the A. diaperinus and for the combination of the two insects. Considered as a "novel food", foods incorporating edible insects represent, in fact, the reintroduction of foods used in the West before the Middle Ages, when the Judeo-Christian tradition began to consider insects as not kosher. Educating consumers about the transition to novel foods can be helped by 3D printing food, as an innovative process that can be used to design creative rich animal protein snacks that make final products more appealing and acceptable to consumers.

The Experimental Development of Emulsions Enriched and Stabilized by Recovering Matter from Spirulina Biomass: Valorization of Residue into a Sustainable Protein Source

Spirulina consists of a cluster of green-colored cyanobacteria; it is commonly consumed as a food or food supplement rich in bioactive compounds with antioxidant activity, predominantly C-phycocyanin (C-PC), which is related to anti-inflammatory action and anticancer potential when consumed frequently. After C-PC extraction, the Spirulina residual biomass (RB) is rich in proteins and fatty acids with the potential for developing food products, which is interesting from the circular economy perspective. The present work aimed to develop a vegan oil-in-water emulsion containing different contents of Spirulina RB, obtaining a product aligned with current food trends. Emulsions with 3.0% (w/w) of proteins were prepared with different chickpea and Spirulina RB ratios. Emulsifying properties were evaluated regarding texture and rheological properties, color, antioxidant activity, and droplet size distribution. The results showed that it was possible to formulate stable protein-rich emulsions using recovering matter rich in protein from Spirulina as an innovative food ingredient. All the concentrations used of the RB promoted the formulation of emulsions presenting interesting rheological parameters compared with a more traditional protein source such as chickpea. The emulsions were also a source of antioxidant compounds and maintained the color for at least 30 days after production.

Poly (diglycerol adipate) variants as enhanced nanocarrier replacements in drug delivery applications

Sustainably derived poly(glycerol adipate) (PGA) has been deemed to deliver all the desirable features expected in a polymeric scaffold for drug-delivery, including biodegradability, biocompatibility, self-assembly into nanoparticles (NPs) and a functionalisable pendant group. Despite showing these advantages over commercial alkyl polyesters, PGA suffers from a series of key drawbacks caused by poor amphiphilic balance. This leads to weak drug-polymer interactions and subsequent low drug-loading in NPs, as well as low NPs stability. To overcome this, in the present work, we applied a more significant variation of the polyester backbone while maintaining mild and sustainable polymerisation conditions. We have investigated the effect of the variation of both hydrophilic and hydrophobic segments upon physical properties and drug interactions as well as self-assembly and NPs stability. For the first time we have replaced glycerol with the more hydrophilic diglycerol, as well as adjusting the final amphiphilic balance of the polyester repetitive units by incorporating the more hydrophobic 1,6-n-hexanediol (Hex). The properties of the novel poly(diglycerol adipate) (PDGA) variants have been compared against known polyglycerol-based polyesters. Interestingly, while the bare PDGA showed improved water solubility and diminished self-assembling ability, the Hex variation demonstrated enhanced features as a nanocarrier. In this regard, PDGAHex NPs were tested for their stability in different environments and for their ability to encode enhanced drug loading. Moreover, the novel materials have shown good biocompatibility in both in vitro and in vivo (whole organism) experiments.

Development of a Clean Label Mayonnaise Using Fruit Flour

Over the past few years, clean label food has been growing, meaning that consumers are searching for shorter and simpler ingredient lists composed of familiar and natural ingredients. The objective of the present work was to develop a vegan clean label mayonnaise, replacing the additives with fruit flour obtained from fruit reduced commercial value. The mayonnaises were prepared by replacing the egg yolk with 1.5% (w/w) lupin and faba proteins, while fruit flour (apple, nectarine, pear, and peach flour) was incorporated to substitute sugar, preservatives, and colorants. Texture profile analysis and rheology-small amplitude oscillatory measurements were performed to evaluate the impact of the fruit flour on mechanical properties. The mayonnaise antioxidant activity was also analyzed in terms of color, pH, microbiology, and stability measurements. The results showed that mayonnaises produced with fruit flour had better structure parameters in terms of viscosity, and texture, but also improved pH and antioxidant activity (p < 0.05) compared to the standard mayonnaise (mayonnaise without fruit flour). The incorporation of this ingredient into mayonnaise increases the antioxidant potential, though it is in lower concentrations compared to the fruit flours that compose them. Nectarine mayonnaise showed the most promising results in terms of texture and antioxidant capacity (11.30 mg equivalent of gallic acid/100 g).

Investigation into the Physicochemical and Textural Properties of an Iron-Rich 3D-Printed Hybrid Food

In the context of dietary transition, blending animal-source protein with plant-source protein offers a promising way to exploit their nutritional complementarity. This study investigates the feasibility of formulating an iron-rich hybrid food product blending plant-source and animal-source protein ingredients for iron-deficient populations. Using a commercial 3D-food printer, two different-shaped products composed mainly of pork and chicken liver and red lentils were designed. After baking at 180 °C with 70% steam, the 3D-printed products were packed under two different modified atmospheres (MAP): O₂-MAP (70% oxygen + 30% carbon dioxide) and N₂-MAP (70% nitrogen + 30% carbon dioxide) and stored at 4 °C. pH, water content, a_w, lipid oxidation, heme iron and non-heme iron contents and textural properties were measured after 0, 7, 14 and 21 days in storage. After 21 days in storage, the 3D-printed hybrid products had an iron content of around 13 mg/100 g, regardless of the product form and packaging method. However, O₂-MAP products showed significant (p < 0.05) time-course changes from day 0 to day 7, i.e., an increase in lipid oxidation, a decrease in heme iron content and an increase in product hardness, gumminess and chewiness. This work opens prospects for developing hybrid food products that upvalue animal by-products.

Impact of Grass Pea Sweet Miso Incorporation in Vegan Emulsions: Rheological, Nutritional and Bioactive Properties

Grass pea (Lathyrus sativus L.) is a pulse with historical importance in Portugal, but that was forgotten over time. Previous to this work, an innovative miso was developed to increase grass pea usage and consumption, using fermentation as a tool to extol this ingredient. Our work's goal was to develop a new vegan emulsion with added value, using grass pea sweet miso as a clean-label ingredient, aligned with the most recent consumer trends. For this, a multidisciplinary approach with microbiological, rheological and chemical methods was followed. Grass pea sweet miso characterization revealed a promising ingredient in comparison with soybean miso, namely for its low fat and sodium chloride content and higher content in antioxidant potential. Furthermore, in vitro antimicrobial activity assays showed potential as a preservation supporting agent. After grass pea sweet miso characterization, five formulations with 5-15% (w/w) of miso were tested, with a vegan emulsion similar to mayonnaise as standard. The most promising formulation, 7.5% (w/w) miso, presented adequate rheological properties, texture profile and fairly good stability, presenting a unimodal droplet size distribution and stable backscattering profile. The addition of 0.1% (w/w) psyllium husk, a fiber with great water-intake capacity, solved the undesirable release of exudate from the emulsion, as observed on the backscattering results. Furthermore, the final product presented a significantly higher content of phenolic compounds and antioxidant activity in comparison with the standard vegan emulsion.

Turning Food Protein Waste into Sustainable Technologies

For each kilogram of food protein wasted, between 15 and 750 kg of CO2 end up in the atmosphere. With this alarming carbon footprint, food protein waste not only contributes to climate change but also significantly impacts other environmental boundaries, such as nitrogen and phosphorus cycles, global freshwater use, change in land composition, chemical pollution, and biodiversity loss. This contrasts sharply with both the high nutritional value of proteins, as well as their unique chemical and physical versatility, which enable their use in new materials and innovative technologies. In this review, we discuss how food protein waste can be efficiently valorized not only by reintroduction into the food chain supply but also as a template for the development of sustainable technologies by allowing it to exit the food-value chain, thus alleviating some of the most urgent global challenges. We showcase three technologies of immediate significance and environmental impact: biodegradable plastics, water purification, and renewable energy. We discuss, by carefully reviewing the current state of the art, how proteins extracted from food waste can be valorized into key players to facilitate these technologies. We furthermore support analysis of the extant literature by original life cycle assessment (LCA) examples run ad hoc on both plant and animal waste proteins in the context of the technologies considered, and against realistic benchmarks, to quantitatively demonstrate their efficacy and potential. We finally conclude the review with an outlook on how such a comprehensive management of food protein waste is anticipated to transform its carbon footprint from positive to negative and, more generally, have a favorable impact on several other important planetary boundaries.

Tenebrio molitor as a Clean Label Ingredient to Produce Nutritionally Enriched Food Emulsions

Tenebrio molitor flour, a sustainable source of protein and bioactive compounds, was used as a clean label ingredient in order to reformulate a commercial hummus sauce, replacing egg yolk and modified starch, improving its nutritional quality. For this purpose, the impact of different concentrations of insect flour on the sauce was studied. Rheology properties, texture profile analysis, and the microstructure of the sauces were analyzed. Nutritional profile analysis was carried out, as well as bioactivity, namely the total phenolic content and the antioxidant capacity. Sensory analysis was conducted to determine the consumer's acceptance. At low concentrations (up to 7.5% of T. molitor flour) the sauce structure remained practically unchanged. However, for higher additions of T. molitor (10% and 15%), a loss of firmness, adhesiveness and viscosity was observed. Structure parameters such as elastic modulus (G') at 1 Hz of the sauces with 10% and 15% were significantly lower than the commercial sauce, indicating a loss of structure caused by Tenebrio flour incorporation. Although the formulation with 7.5% T. molitor flour was not the best rated in the sensory analysis, it showed a higher antioxidant capacity compared to the commercial standard. In addition, this formulation also presented the highest concentration in total phenolic compounds (16.25 mg GAE/g) and significantly increased the content of proteins (from 4.25% to 7.97%) and some minerals, compared to the standard.

Application of Protein in Extrusion-Based 3D Food Printing: Current Status and Prospectus

Extrusion-based 3D food printing is one of the most common ways to manufacture complex shapes and personalized food. A wide variety of food raw materials have been documented in the last two decades for the fabrication of personalized food for various groups of people. This review aims to highlight the most relevant and current information on the use of protein raw materials as functional 3D food printing ink. The functional properties of protein raw materials, influencing factors, and application of different types of protein in 3D food printing were also discussed. This article also clarified that the effective and reasonable utilization of protein is a vital part of the future 3D food printing ink development process. The challenges of achieving comprehensive nutrition and customization, enhancing printing precision and accuracy, and paying attention to product appearance, texture, and shelf life remain significant.

3D Food Printing: Principles of Obtaining Digitally-Designed Nourishment

Three-dimensional printing (3DP) technology gained significance in the fields of medicine, engineering, the food industry, and molecular gastronomy. 3D food printing (3DFP) has the main objective of tailored food manufacturing, both in terms of sensory properties and nutritional content. Additionally, global challenges like food-waste reduction could be addressed through this technology by improving process parameters and by sustainable use of ingredients, including the incorporation of recovered nutrients from agro-industrial by-products in printed nourishment. The aim of the present review is to highlight the implementation of 3DFP in personalized nutrition, considering the technology applied, the texture and structure of the final product, and the integrated constituents like binding/coloring agents and fortifying ingredients, in order to reach general acceptance of the consumer. Personalized 3DFP refers to special dietary necessities and can be promising to prevent different non-communicable diseases through improved functional food products, containing bioactive compounds like proteins, antioxidants, phytonutrients, and/or probiotics.

3D-Printed Mucoadhesive Collagen Scaffolds as a Local Tetrahydrocurcumin Delivery System

Native collagen doughs were processed using a syringe-based extrusion 3D printer to obtain collagen scaffolds. Before processing, the rheological properties of the doughs were analyzed to determine the optimal 3D printing conditions. Samples showed a high shear-thinning behavior, reported beneficial in the 3D printing process. In addition, tetrahydrocurcumin (THC) was incorporated into the dough formulation and its effect on collagen structure, as well as the resulting scaffold's suitability for wound healing applications, were assessed. The denaturation peak observed by differential scanning calorimetry (DSC), along with the images of the scaffolds' surfaces assessed using scanning electron microscopy (SEM), showed that the fibrillar structure of collagen was maintained. These outcomes were correlated with X-ray diffraction (XRD) results, which showed an increase of the lateral packaging of collagen chains was observed in the samples with a THC content up to 4%, while a higher content of THC considerably decreased the structural order of collagen. Furthermore, physical interactions between collagen and THC molecules were observed using Fourier transform infrared (FTIR) spectroscopy. Additionally, all samples showed swelling and a controlled release of THC. These results along with the mucoadhesive properties of collagen suggested the potential of these THC-collagen scaffolds as sustained THC delivery systems.

3D Printing of Steak-like Foods Based on Textured Soybean Protein

Due to the lack of a sufficient amount of animal protein and the pursuit of health and reduced environmental impact, the global demand for plant protein is increasing. This study endeavors to using textured soybean protein (TSP) or drawing soy protein (DSP) as raw materials to produce steak-like foods through 3D printing technology. The textural difference between fried 3D printed samples and fried commercial chicken breast (control) was studied. The results show that different ink substrates (TSP and DSP) and hydrocolloids (xanthan gum, konjac gum, sodium alginate, guar gum, sodium carboxymethyl cellulose, and hydroxyethyl cellulose) were the keys to successful printing. The ink composed of TSP and xanthan gum had the best printing characteristics and sample integrity after frying. It was found that different infilling patterns and infill rates had a significant effect on the texture properties of the fried samples. When the triangle infilling pattern was used at an infill rate of 60%, the product had had the closest hardness (2585.13 ± 262.55), chewiness (1227.18 ± 133.00), and gumminess (1548.09 ± 157.82) to the control sample. This work proved the feasibility of using 3D printing based on plant protein to produce steak-like food with texture properties similar to chicken breast.

Plasma-Based Bioinks for Extrusion Bioprinting of Advanced Dressings

Extrusion bioprinting based on the development of novel bioinks offers the possibility of manufacturing clinically useful tools for wound management. In this study, we show the rheological properties and printability outcomes of two advanced dressings based on platelet-rich plasma (PRP) and platelet-poor plasma (PPP) blended with alginate and loaded with dermal fibroblasts. Measurements taken at 1 h, 4 days, and 18 days showed that both the PRP- and PPP-based dressings retain plasma and platelet proteins, which led to the upregulation of angiogenic and immunomodulatory proteins by embedded fibroblasts (e.g., an up to 69-fold increase in vascular endothelial growth factor (VEGF), an up to 188-fold increase in monocyte chemotactic protein 1 (MCP-1), and an up to 456-fold increase in hepatocyte growth factor (HGF) 18 days after printing). Conditioned media harvested from both PRP and PPP constructs stimulated the proliferation of human umbilical vein endothelial cells (HUVECs), whereas only those from PRP dressings stimulated HUVEC migration, which correlated with the VEGF/MCP-1 and VEGF/HGF ratios. Similarly, the advanced dressings increased the level of interleukin-8 and led to a four-fold change in the level of extracellular matrix protein 1. These findings suggest that careful selection of plasma formulations to fabricate wound dressings can enable regulation of the molecular composition of the microenvironment, as well as paracrine interactions, thereby improving the clinical potential of dressings and providing the possibility to tailor each composition to specific wound types and healing stages.

Design of a Waterborne Polyurethane-Urea Ink for Direct Ink Writing 3D Printing

In this work, polycaprolactone-polyethylene glycol (PCL-PEG) based waterborne polyurethane-urea (WBPUU) inks have been developed for an extrusion-based 3D printing technology. The WBPUU, synthesized from an optimized ratio of hydrophobic polycaprolactone diol and hydrophilic polyethylene glycol (0.2:0.8) in the soft segment, is able to form a physical gel at low solid contents. WBPUU inks with different solid contents have been synthesized. The rheology of the prepared systems was studied and the WBPUUs were subsequently used in the printing of different pieces to demonstrate the relationship between their rheological properties and their printing viability, establishing an optimal window of compositions for the developed WBPUU based inks. The results showed that the increase in solid content results in more structured inks, presenting a higher storage modulus as well as lower tan δ values, allowing for the improvement of the ink's shape fidelity. However, an increase in solid content also leads to an increase in the yield point and viscosity, leading to printability limitations. From among all printable systems, the WBPUU with a solid content of 32 wt% is proposed to be the more suitable ink for a successful printing performance, presenting both adequate printability and good shape fidelity, which leads to the realization of a recognizable and accurate 3D construct and an understanding of its relationship with rheological parameters.

Proteins from Agri-Food Industrial Biowastes or Co-Products and Their Applications as Green 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.

Strengthening of Porcine Plasma Protein Superabsorbent Materials through a Solubilization-Freeze-Drying Process

The replacement of common acrylic derivatives by biodegradable materials in the formulation 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 materials 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.

Semi-solid extrusion 3D printing in drug delivery and biomedicine: Personalised solutions for healthcare challenges

Three-dimensional (3D) printing is an innovative additive manufacturing technology, capable of fabricating unique structures in a layer-by-layer manner. Semi-solid extrusion (SSE) is a subset of material extrusion 3D printing, and through the sequential deposition of layers of gel or paste creates objects of any desired size and shape. In comparison to other extrusion-based technologies, SSE 3D printing employs low printing temperatures which makes it suitable for drug delivery and biomedical applications, and the use of disposable syringes provides benefits in meeting critical quality requirements for pharmaceutical use. Besides pharmaceutical manufacturing, SSE 3D printing has attracted increasing attention in the field of bioelectronics, particularly in the manufacture of biosensors capable of measuring physiological parameters or as a means to trigger drug release from medical devices. This review begins by highlighting the major printing process parameters and material properties that influence the feasibility of transforming a 3D design into a 3D object, and follows with a discussion on the current SSE 3D printing developments and their applications in the fields of pharmaceutics, bioprinting and bioelectronics. Finally, the advantages and limitations of this technology are explored, before focusing on its potential clinical applications and suitability for preparing personalised medicines.

Novel evaluation technology for the demand characteristics of 3D food printing materials: a review

As a recently developed way of food manufacturing - 3D printing - is bringing about a revolution in the food industry. Rheological and mechanical properties of food material being printed are the determinants of their printability. Therefore, it is important to analyze the requirements of different 3D printing technologies on material properties and to evaluate the performance of the printed materials. In this review, the printing characteristics and classification of food materials are discussed. The four commonly used 3D printing techniques e.g. extrusion-based printing, selective sintering printing (SLS), binder jetting, and inkjet printing, are outlined along with suitable material characteristics required for each printing technique. Finally, recent technologies for evaluation of 3D printed products including low field nuclear magnetic resonance (LF-NMR), computer numerical simulation, applied reference material, morphological identification, and some novel instrumental analysis techniques are highlighted.