Construction of 3D printed reduced-fat meat analogue by emulsion gels. Part I: Flow behavior, thixotropic feature, and network structure of soy protein-based inks

State of the art, challenges, and future prospects for the multi-material 3D printing of plant-based meat

The emergence of innovative plant-based meat analogs, replicating the flavor, texture, and appearance of animal meat cuts, is deemed crucial for sustainably feeding a growing population while mitigating the environmental impact associated with livestock farming. Multi-material 3D food printing (MM3DFP) has been proposed as a potentially disruptive technology for manufacturing the next generation of plant-based meat analogs. This article provides a comprehensive review of the state of the art, addressing various aspects of 3D printing in the realm of plant-based meat. The disruptive potential of printed meat analogs is discussed with particular emphasis on protein-rich, lipid-rich, and blood-mimicking food inks. The printing parameters, printing requirements, and rheological properties at the different printing stages are addressed in detail. As food rheology plays a key role in the printing process, an appraisal of this subject is performed. Post-printing treatments are assessed based on the extent of improvement in the quality of 3D-printed plant-based meat analogs. The meat-mimicking potential is revealed through sensory attributes, such as texture and flavor. Furthermore, there has been limited research into food safety and nutrition. Economically, the 3D printing of plant-based meat analogs demonstrates significant market potential, contingent upon innovative decision-making strategies and supportive policies to enhance consumer acceptance. This review examines the current limitations of this technology and highlights opportunities for future developments.

Exploring gelation properties and structural features on 3D printability of compound proteins emulsion gels: Emphasizing pH-regulated non-covalent interactions with xanthan gum

Rational regulation of pH and xanthan gum (XG) concentration has the potential to modulate interactions among macromolecules and enhance 3D printability. This study investigated non-covalent interactions between XG and other components within compound proteins emulsion gel systems across varying pH values (4.0-8.0) and XG concentrations (0-1 wt%) and systematically explored impacts of gelation properties and structural features on 3D printability. The results of rheological and structural features indicated that pH-regulated non-covalent interactions were crucial for maintaining structural stability of emulsion gels with the addition of XG. The 3D printability of emulsion gels would be significantly improved through moderate depletion flocculation produced when XG concentration was 0.75 wt% at the pH 6.0. Mechanical properties like viscosity exhibited a strongly negative correlation with 3D printability, whereas structural stability showed a significantly positive correlation. Overall, this study provided theoretical insights for the development of emulsion gels for 3D printing by regulating non-covalent interactions.

Applications of physical and chemical treatments in plant-based gels for food 3D printing

Extrusion-based three-dimensional (3D) printing has been extensively studied in the food manufacturing industry. This technology places particular emphasis on the rheological properties of the printing ink. Gel system is the most suitable ink system and benefits from the composition of plant raw materials and gel properties of multiple components; green, healthy aspects of the advantages of the development of plant-based gel system has achieved a great deal of attention. However, the relevant treatment technologies are still only at the laboratory stage. With a view toward encouraging further optimization of ink printing performance and advances in this field, in this review, we present a comprehensive overview of the application of diverse plant-based gel systems in 3D food printing and emphasize the utilization of different treatment methods to enhance the printability of these gel systems. The treatment technologies described in this review are categorized into three distinct groups, physical, chemical, and physicochemical synergistic treatments. We comprehensively assess the specific application of these technologies in various plant-based gel 3D printing systems and present valuable insights regarding the challenges and opportunities for further advances in this field.

Effect of compositions and physical properties on 3D printability of gels from selected commercial edible insects: Role of protein and chitin

Compositions and rheological properties of alternative protein sources, including honey bee pupa, grasshopper, cricket, earthworm, and scorpion, and their relationships with 3D printing behaviors were investigated. Protein was found to be the major composition in all insects, while chitin exhibited the most variation. At optimal moisture contents, honey bee pupa and earthworm gels displayed sufficient fluidity but resulted in unstable printed structures, as observed visually and microstructurally. Grasshopper and scorpion gels possessed weak fluidity but produced more stable printed structures. Cricket gel exhibited the most balanced flow behavior and self-supportability. Protein-to-chitin mass ratio proved to be a main factor affecting the 3D printing behavior of the gels. Possible mechanisms on how compositions and properties affected the printing behavior of the gels were proposed. Suggestions for improving the 3D printability of insect and invertebrate resembling insect gels were provided based on these proposed mechanisms.

Tailoring the oral sensation and digestive behavior of konjac glucomannan-gelatin binary hydrogel based bigel: Effects of composition and ratio

In the food industry, there is a growing demand for bigels that offer both adaptable oral sensations and versatile delivery properties. Herein, we developed bigels using a binary hydrogel of konjac glucomannan (KGM) and gelatin (G) combined with a stearic acid oleogel. We closely examined how the oleogel/hydrogel volume ratio (φ) and the KGM/G mass ratio (γ) influenced various characteristics of the bigels, including their microstructure, texture, rheological properties, thermal-sensitivity, oral tribology, digestive stability, and nutraceutical delivery efficiency. A noteworthy observation was the structural evolution of the bigels with increasing φ values: transitioning from oleogel-in-hydrogel to a bicontinuous structure, and eventually to hydrogel-in-oleogel. Lower γ values yielded a softer, thermally-responsive bigel, whereas higher γ values imparted enhanced viscosity, stickiness, and spreadability to the bigel. Oral tribology assessments demonstrated that φ primarily influenced the friction sensations at lower chewing intensities. In contrast, γ played a significant role in augmenting oral friction perceptions during more intense chewing. Additionally, φ dictated the controlled release and bioaccessibility of curcumin, while γ determined digestive stability. This study provides valuable insights, emphasizing that through meticulous selection and adjustment of the hydrogel matrix composition, bigels can be custom-fabricated to achieve specific oral sensations and regulated digestive behaviors.

An Overview of Ingredients Used for Plant-Based Meat Analogue Production and Their Influence on Structural and Textural Properties of the Final Product

Plant-based meat analogues are food products made from vegetarian or vegan ingredients that are intended to mimic taste, texture and appearance of meat. They are becoming increasingly popular as people look for more sustainable and healthy protein sources. Furthermore, plant-based foods are marketed as foods with a low carbon footprint and represent a contribution of the consumers and the food industry to a cleaner and a climate-change-free Earth. Production processes of plant-based meat analogues often include technologies such as 3D printing, extrusion or shear cell where the ingredients have to be carefully picked because of their influence on structural and textural properties of the final product, and, in consequence, consumer perception and acceptance of the plant-based product. This review paper gives an extensive overview of meat analogue components, which affect the texture and the structure of the final product, discusses the complex interaction of those ingredients and reflects on numerous studies that have been performed in that area, but also emphasizes the need for future research and optimization of the mixture used in plant-based meat analogue production, as well as for optimization of the production process.

Plant-Based Meat Proteins: Processing, Nutrition Composition, and Future Prospects

The growing need for plant-based meat alternatives promotes the rapid progress of the food industry. Processing methods employed in plant-based meat production are critical to preserving and enhancing their nutritional content and health benefits, directly impacting consumer acceptance. Unlike animal-based food processing, the efficiency of protein extraction and processing methods plays a crucial role in preserving and enriching the nutritional content and properties. To better understand the factors and mechanisms affecting nutrient composition during plant-based meat processing and identify key processing steps and control points, this work describes methods for extracting proteins from plants and processing techniques for plant-based products. We investigate the role of nutrients and changes in the nutrients during plant protein product processing. This article discusses current challenges and prospects.

Stabilization of capsanthin in physically-connected hydrogels: Rheology property, self-recovering performance and syringe/screw-3D printing

This work presented a facile way of stabilizing capsanthin by physically-connected soft hydrogels via utilizing specially-structured polysaccharides, and investigated rheological properties, self-recovering mechanism and 3D printability. The functionalized hydrogels demonstrated excellent color quality including redness, yellowness index and hue with great storage stability and visual perception. The soft hydrogels fabricated with properly sequenced polyglyceryl fatty acid esters, β-cyclodextrin, chitosan, and low-content capsanthin possessed outstanding extrudability, appropriate yield stress, reasonable mechanical strength, rational elasticity and structure sustainability. Furthermore, the self-recovering properties based on hydrogen bonds, host-guest interactions and electrostatic interactions were revealed and verified by structural, zeta potential, micro-morphological, zeta potential, thixotropic, creep-recovery, and macroscopic/microscopic characterizations. Along with excellent antioxidant performance, the subsequent 3D printing onto bread with complex models elucidated the high geometry accuracy and great sensory characters. The sequenced physically-connected hydrogels incorporated with capsanthin can provide new insights on stabilizing hydrophobic biomaterials and developing the 3D printed exquisite, innovative food.

Plant-based meat analogs and fat substitutes, structuring technology and protein digestion: A review

There is currently an increasing trend in the consumption of meat analogs and fat substitutes due to the health hazards by excessive consumption of meat. Simulating the texture and mouthfeel of meat through structured plant-derived polymers has become a popular processing method. In this review, the mechanical structuring technology of plant polymers for completely replacing real meat is mainly introduced in this review, which mainly focuses on the parameters and principles of mechanical equipment for the production of vegan meat. The difference in composition between plant meat and real meat is mainly reflected in the protein, and particular attention should be paid to the digestive characteristics of plant meat protein in the gastrointestinal tract. Therefore, the differences in the protein digestibility properties of meat analogs and real meat is discussed in this review, focusing primarily on protein digestibility and peptide/amino acid composition of mechanically structured vegan meats. In terms of fat substitutes for meat products, the types of plant polymer colloidal systems used for meat fat substitutes is comprehensively introduced, including emulsion, hydrogel and oleogel.

Plant-based meat analogue of soy proteins by the multi-strain solid-state mixing fermentation

In order to mitigate or reduce global environmental concerns, health issues, sustainability and animal welfare issues, artificial meat presents a potential solution to consumers' demand for meat. In this study, strains such as Rhodotorula mucilaginosa and Monascus purpureus that can produce meat-like pigments were first identified and used in soy protein plant-base fermentation, where fermentation parameters as well as inoculum size were determined to simulate plant-base meat analogue (PBMA). Meanwhile, the resemblance between the fermented soy products and the fresh meat was examined in terms of color, texture, and flavor characteristics. Furthermore, the addition of Lactiplantibacillus plantarum can perform reassortment and fermentation simultaneously to improve the quality of soy fermentation products in terms of texture and flavor. The results offer a novel way to produce PBMA and also shed light on future research into plant-based meat-like products with the appropriate meat characteristics.

Rheological property, β-carotene stability and 3D printing characteristic of whey protein isolate emulsion gels by adding different polysaccharides

Emulsion gels with unique structural and mechanical properties have promising applications in 3D food printing. The purpose of this paper was to investigate the rheological property, β-carotene stability and 3D printing characteristic of whey protein isolate (WPI) emulsion gels by adding guar gum (GG), locust bean gum (LBG), xanthan gum (XG) and gum arabic (GA). The results showed that all samples exhibited shear thinning behavior and elastic characteristic. XG could reduce water mobility and increase WHC of WPI emulsion gel. The disulfide bond was the main chemical molecular force of emulsion gels, and XG significantly increased the hydrophobic interactions. GG and LBG increased gel strength, hardness and gumminess, reduced springiness, cohesiveness and chewiness of emulsion gels. GG sample had the best printing performance, more uniform network structure and better stability of β-carotene. This study provided a theoretical basis for 3D printing functional food.

3D printed macroporous scaffolds of PCL and inulin-g-P(D,L)LA for bone tissue engineering applications

Bone repair and tissue-engineering (BTE) approaches require novel biomaterials to produce scaffolds with required structural and biological characteristics and enhanced performances with respect to those currently available. In this study, PCL/INU-PLA hybrid biomaterial was prepared by blending of the aliphatic polyester poly(ε-caprolactone) (PCL) with the amphiphilic graft copolymer Inulin-g-poly(D,L)lactide (INU-PLA) synthetized from biodegradable inulin (INU) and poly(lactic acid) (PLA). The hybrid material was suitable to be processed using fused filament fabrication 3D printing (FFF-3DP) technique rendering macroporous scaffolds. PCL and INU-PLA were firstly blended as thin films through solvent-casting method, and then extruded by hot melt extrusion (HME) in form of filaments processable by FFF-3DP. The physicochemical characterization of the hybrid new material showed high homogeneity, improved surface wettability/hydrophilicity as compared to PCL alone, and right thermal properties for FFF process. The 3D printed scaffolds exhibited dimensional and structural parameters very close to those of the digital model, and mechanical performances compatible with the human trabecular bone. In addition, in comparison to PCL, hybrid scaffolds showed an enhancement of surface properties, swelling ability, and in vitro biodegradation rate. In vitro biocompatibility screening through hemolysis assay, LDH cytotoxicity test on human fibroblasts, CCK-8 cell viability, and osteogenic activity (ALP evaluation) assays on human mesenchymal stem cells showed favorable results.

Developments in Plant Proteins Production for Meat and Fish Analogues

In recent years, there have been significant developments in plant proteins production for meat and fish analogues. Some of the key developments include the use of new plant protein sources such as soy, legumes, grains, potatoes, and seaweed, as well as insect proteins, leaf proteins, mushrooms, and microbial proteins. Furthermore, to improve the technological and functional properties of plant proteins, they can be subjected to traditional and unconventional treatments such as chemical (glycosylation, deamidation, phosphorylation, and acylation), physical (pulsed electric fields, ultrasound, high hydrostatic pressure, dynamic high-pressure treatment, and cold plasma), and biological (fermentation and enzymatic modification). To obtain the high quality and the desired texture of the food product, other ingredients besides proteins, such as water, fat, flavors, binders, dyes, vitamins, minerals, and antioxidants, also have to be used. The final product can be significantly influenced by the matrix composition, variety of ingredients, and water content, with the type of ingredients playing a role in either enhancing or constraining the desired texture of the food. There are several types of technologies used for meat and fish analogues production, including extrusion, shear cell technology, spinning, 3D printing, and others. Overall, the technologies used for meat and fish analogues production are constantly evolving as new innovations are developed and existing methods are improved. These developments have led to the creation of plant-based products that have a similar texture, taste, and nutritional profile to meat and fish, making them more appealing to consumers seeking alternatives to animal-based products.

Production of Fish Analogues from Plant Proteins: Potential Strategies, Challenges, and Outlook

Fish products are consumed by human beings as a high-quality protein source. However, overfishing, and pollution puts out an urgent call to seek a new strategy to substitute fish protein for secure eco-sustainability. Plant-based fish analogs, which mimic the structure, texture, and flavor of fish meat products, are a rapid-growing segment of the food products. The purpose of this review is to discuss the feasibility and potential strategies for developing plant-based fish analog. The nutritional properties, especially the protein quality of plant-based fish analogs, were discussed. Furthermore, a thorough comparison was made between fish and terrestrial animal muscle structures, including both macroscopical and microscopical structures. Potential processing technologies for producing plant-based fish analogs from plant proteins and approaches for the characterization of the fish analog structures were elaborated. Comparing all the current processing techniques, extrusion is the predominately used technique in the current industry. At the same time, 3D-printing and electrospinning have shown the prominent potential of mimicking fish muscle structure as bottom-up approaches. Finally, key challenges and future research were discussed for the potential commercialization of plant-based fish analogues. The primary focus of this review covers the innovative works that were indexed in the Web of Science Core Collection in the past five years.

Construction of 3D printed meat analogs from plant-based proteins: improving the printing performance of soy protein- and gluten-based pastes facilitated by rice protein

Additive technology (3D printing) is increasingly being used to produce plant-based meat analogs. However, there are several challenges to fabricating meat analogs using this technology: (i) the protein content in the final printed product is often too low to match the nutritional profile of real meat; (ii) it is often difficult to accurately mimic the textural and structural attributes of real meat using existing plant protein edible inks. In this study, the rheological properties and printing performance of edible inks produced from soy protein isolate (SPI), wheat gluten (WG), and rice protein (RP) were investigated. Our goal was to mix SPI, WG, RP powders to develop a high-protein edible ink (25% of total dry matter content) that can be used to create 3D-printed meat analogs. The rheological properties, moisture distribution, texture, microstructure, and printing performance (fidelity and stability) of protein pastes with different SPI-WG-to-RP ratios were measured. These protein-enriched inks exhibited pseudoplastic behavior with viscoelastic properties. The apparent viscosity and storage modulus of these pastes decreased with increasing rice protein proportion, which improved their 3D printing performance, such as hardness, support force, and plasticization. These edible inks prepared by mixed protein may be useful for 3D printing of plant-based foods.

Formulation and stabilization of high internal phase emulsions: Stabilization by cellulose nanocrystals and gelatinized soluble starch

In this work, high internal phase emulsions (HIPEs) stabilized by naturally derived cellulose nanocrystals (CNC) and gelatinized soluble starch (GSS) were fabricated to stabilize oregano essential oil (OEO) in the absence of surfactant. The physical properties, microstructures, rheological properties, and storage stability of HIPEs were investigated by adjusting CNC contents (0.2, 0.3, 0.4 and 0.5 wt%) and starch concentration (4.5 wt%). The results revealed that CNC-GSS stabilized HIPEs exhibited good storage stability within one month and the smallest droplets size at a CNC concentration of 0.4 wt%. The emulsion volume fractions of 0.2, 0.3, 0.4 and 0.5 wt% CNC-GSS stabilized HIPEs after centrifugation reached 77.58, 82.05, 94.22, and 91.41 %, respectively. The effect of native CNC and GSS were analyzed to understand the stability mechanisms of HIPEs. The results revealed that CNC could be used as an effective stabilizer and emulsifier to fabricate the stable and gel-like HIPEs with tunable microstructure and rheological properties.

Recent Advances in the Processing and Manufacturing of Plant-Based Meat

Plant protein technology is a core area of biotechnology to ease the problem of human protein demand. Plant-based meat based on plant protein technology is a growing concern by global consumers in alleviating environmental pollution, cutting down resources consumption, and improving animal welfare. Plant-based meat simulates the texture, taste, and appearance of animal meat by using protein, lipid, carbohydrate, and other plant nutrients as the main substances. This review summarizes the main components of plant-based meat, processing technology, standard formula, market competition, and formula and texture of future research directions. According to the existing methods of plant-based meat fiber forming, the development process and characteristics of four production processes and equipment of plant-based meat spinning, extrusion, shearing, and 3D printing are emphatically expounded. The processing principles and methods of different processing technologies in plant-based meat production are summarized. The production process and equipment of plant-based meat will pay more attention to the joint production of various processes to improve the defects of plant-based meat production process.

Insights into the Supramolecular Structure and Degradation Mechanisms of Starch from Different Botanical Sources as Affected by Extrusion-based 3D Printing

Extrusion-based 3D printing has emerged as the most versatile additive manufacturing technique for the printing of practically any material. However, 3D printing of functional materials often activates thermo-mechanical degradation, which affects the 3D shape quality. Herein, we describe the structural changes of eight different starch sources (normal or waxy) as a consequence of the temperature of an extrusion-based 3D printing system through in-depth characterization of their molecular and structural changes. The combination of size-exclusion chromatography, small-angle X-ray scattering, X-ray diffraction, dynamic viscoelasticity measurements, and in vitro digestion has offered an extensive picture of the structural and biological transformations of starch varieties. Depending on the 3D printing conditions, either gelatinization was attained ("moderate" condition) or single-amylose helix formation was induced ("extreme" condition). The stiff amylopectin crystallites in starch granules were more susceptible to thermo-mechanical degradation compared to flexible amorphous amylose. The crystalline morphology of the starch varieties varied from B-type crystallinity for the starch 3D printing at the "moderate" condition to a mixture of C- and V-type crystallinity regarding the "extreme" condition. The "extreme" condition reduced the viscoelasticity of 3D-printed starches but increased the starch digestibility rate/extent. In contrast, the "moderate" condition increased the viscoelastic moduli, decreasing the starch digestion rate/extent. This was more considerable mainly regarding the waxy starch varieties. Finally, normal starch varieties presented a well-defined shape fidelity, being able to form a stable structure, whereas waxy starches exhibited a non-well-defined structure and were not able to maintain their integrity after printing. The results of this research allow us to monitor the degradability of a variety of starch cultivars to create starch-based 3D structures, in which the local structure can be controlled based on the 3D printing parameters.

Light-dimerization telechelic alginate-based amphiphiles reinforced Pickering emulsion for 3D printing

Functional Pickering emulsions that depend on the interparticle interactions hold promise for building template materials. A novel coumarin-grafting alginate-based amphiphilic telechelic macromolecules (ATMs) undergoing photo-dimerization enhanced particle-particle interactions and changed the self-assembly behavior in solutions. The influence of self-organization of polymeric particles on the droplet size, microtopography, interfacial adsorption and viscoelasticity of Pickering emulsions were further determined by multi-scale methodology. Results showed that stronger attractive interparticle interactions of ATMs (post-UV) endowed Pickering emulsion with small droplet size (16.8 μm), low interfacial tension (9.31 mN/m), thick interfacial film, high interfacial viscoelasticity and adsorption mass, and well stability. The high yield stress, outstanding extrudability (n₁ < 1), high structure maintainability, and well shape retention ability, makes them ideal inks for direct 3D printing without any additions. The ATMs provides an increased capacity to produce stable Pickering emulsions with tailoring their interfacial performances and, providing a platform for fabricating and developing alginate-based Pickering emulsion-templated materials.

Prospects for Plant-Based Meat: Current Standing, Consumer Perceptions, and Shifting Trends

Dietary habits have a substantial influence on both planet and individual health. High intake of animal products has significant negative effects on the environment and on human health; hence, a reduction in meat consumption is necessary. The transition towards plant-based meat (PBM) is one of the potential solutions for environmental and health issues. To achieve this goal, it is important to understand the dietary habits and demands of consumers. This review was designed with a focus on PBM alternatives, dietary shifts during the COVID-19 pandemic, the drivers of consumers' perceptions in various countries, and the measures that can promote the shift towards PBM. The PBM market is predicted to grow with rising awareness, familiarity, and knowledge in the coming years. Companies must focus on the categories of anticipated benefits to aid consumers in making the switch to a diet higher in PBM alternatives if they want to win over the target market.

Self-assembled zein organogels as in situ forming implant drug delivery system and 3D printing ink

Recently, biomedical applications of organogels have been increasing; however, there is a demand for bio-based polymers. Here, we report self-assembled zein organogels in N-methyl pyrrolidone (NMP), Dimethyl sulfoxide (DMSO), and glycerol formal (GF). The gel formation was driven by the solvent's polarity and the hydrogen bonding component of Hansen Solubility Parameters was important in promoting gelation. Gels exhibited shear-thinning and thixotropic properties. Furthermore, water-induced self-assembly of zein allows mechanically robust in situ implant formation by solvent exchange. Ciprofloxacin was incorporated as a model drug and sustained release depending upon the solvent exchange rate was observed. In situ implants in agarose gel retained antibacterial efficacy against S. aureus for more than 14 days. Zein-based organogels were further applied as 3D printing ink and it was found that zein gel in DMSO had superior printability than gels prepared in NMP and GF. Using three solvents to prepare organogels can enable the encapsulation of various drugs and facilitate the preparation of composite gels with other biocompatible polymers. These organogel systems can further be used for developing 3D printed drug delivery systems or scaffolds for tissue engineering.

Bioengineered Lab-Grown Meat-like Constructs through 3D Bioprinting of Antioxidative Protein Hydrolysates

Lab-grown bovine meat analogues are emerging alternatives to animal sacrifices for cultured meat production. The most challenging aspect of the production process is the rapid proliferation of cells and establishment of the desired 3D structure for mass production. In this study, we developed a direct ink writing-based 3D-bioprinted meat culture platform composed of 6% (w/v) alginate and 4% (w/v) gelatin (Alg/Gel)-based hydrogel scaffolds supplemented with naturally derived protein hydrolysates (PHs; 10%) from highly nutritive plants (soybean, pigeon pea, and wheat), and some selected edible insects (beetles, crickets, and mealworms) on in vitro proliferation of bovine myosatellite cells (bMSCs) extracted from fresh meat samples. The developed bioink exhibited excellent shear-thinning behavior (n < 1) and mechanical stability during 3D bioprinting. Commercial proteases (Alcalase, Neutrase, and Flavourzyme) were used for protein hydrolysis. The resulting hydrolysates exhibited lower-molecular-weight bands (12-50 kDa) than those of crude isolates (55-160 kDa), as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The degree of hydrolysis was higher in the presence of Alcalase for both plant (34%) and insect (62%) PHs than other enzymes. The 3D-printed hydrogel scaffolds displayed excellent bioactivity and stability after 7 days of incubation. The developed prototype structure (pepperoni meat, 20 × 20 × 5 mm) provided a highly stable, nutritious, and mechanically strong structure that supported the rapid proliferation of myoblasts in a low-serum environment during the entire culture period. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay enhanced the free radical reduction of Alcalase- and Neutrase-treated PHs. Furthermore, the bioprinted bMSCs displayed early myogenesis (desmin and Pax7) in the presence of PHs, suggesting its role in bMSC differentiation. In conclusion, we developed a 3D bioprinted and bioactive meat culture platform using Alg/Gel/PHs as a printable and edible component for the mass production of cultured meat.

Ingredients and Process Affect the Structural Quality of Recombinant Plant-Based Meat Alternatives and Their Components

Recombinant plant-based meat alternatives are a kind of product that simulates animal meat with complete structure by assembling plant-tissue protein and other plant-based ingredients. The market is growing rapidly and appears to have a promising future due to the broad culinary applicability of such products. Based on the analysis and summary of the relevant literature in the recent five years, this review summarizes the effects of raw materials and production methods on the structure and quality of specific components (tissue protein and simulated fat) in plant-based meat alternatives. Furthermore, the important roles of tissue and simulated fat as the main components of recombinant plant-based meat alternatives are further elucidated herein. In this paper, the factors affecting the structure and quality of plant-based meat alternatives are analyzed from part to whole, with the aim of contributing to the structural optimization and providing reference for the future development of the plant meat industry.

Application of Emulsion Gels as Fat Substitutes in Meat Products

Although traditional meat products are highly popular with consumers, the high levels of unsaturated fatty acids and cholesterol present significant health concerns. However, simply using plant oil rich in unsaturated fatty acids to replace animal fat in meat products causes a decline in product quality, such as lower levels of juiciness and hardness. Therefore, it is necessary to develop a fat substitute that can ensure the sensory quality of the product while reducing its fat content. Consequently, using emulsion gels to produce structured oils or introducing functional ingredients has attracted substantial attention for replacing the fat in meat products. This paper delineated emulsion gels into protein, polysaccharide, and protein–polysaccharide compound according to the matrix. The preparation methods and the application of the three emulsion gels as fat substitutes in meat products were reviewed. Since it displayed a unique separation structure, the double emulsion was highly suitable for encapsulating bioactive substances, such as functional oils, flavor components, and functional factors, while it also exhibited significant potential for developing low-fat or functional healthy meat products. This paper summarized the studies involving the utilization of double emulsion and gelled double emulsion as fat replacement agents to provide a theoretical basis for related research and new insight into the development of low-fat meat products.

Dual-Grafting of Microcrystalline Cellulose by Tea Polyphenols and Cationic ε-Polylysine to Tailor a Structured Antimicrobial Soy-Based Emulsion for 3D Printing

An imperative processing way to produce 3D printed structures with enhanced multifunctional properties is printing inks in the form of a gel-like colloidal emulsion. The surface-modified microcrystalline cellulose (MCC) is an excipient of outstanding merit as a particulate emulsifier to manufacture a stable Pickering emulsion gel. The tuning of the MCC structure by cationic antimicrobial compounds, such as ε-polylysine (ε-PL), can offer a surface activity with an antimicrobial effect. However, the MCC/ε-PL lacks the appropriate emulsifying ability due to the development of electrostatic complexes. To overcome this challenge, (i) a surface-active MCC conjugate was synthesized by a sustainable dual-grafting technique (ii) to produce a highly stable therapeutic soy-based Pickering emulsion gel (iii) for potential application in 3D printing. In this regard, the tea polyphenols were initially introduced into MCC by the free-radical grafting method to decrease the charge density of anionic MCC. Then, the antioxidative MCC-g-tea polyphenols were reacted by ε-PL to produce a dual-grafted therapeutic MCC conjugate (micro-biosurfactant), stabilizing the soy-based emulsion system. The results indicated that the dual-grafted micro-biosurfactant formed a viscoelastic and thixotropic soy-based emulsion gel with reduced droplet size and long-term stability. Besides, there was an improvement in the interfacial adsorption features of soy-protein particles after micro-biosurfactant incorporation, where the interfacial pressure and surface dilatational viscoelastic moduli were enhanced. Consequently, it was revealed that the therapeutic Pickering emulsion gel was more suitable to manufacture a well-defined 3D architecture with high resolution and retained permanent deformation after unloading (i.e., a recoverable matrix). This work established that the modification of the MCC backbone by tea polyphenols and ε-PL advances its bioactive properties and emulsifying performance, which finally obtains a soy-based 3D printed structure with noteworthy mechanical strength.

Development of an Antioxidative Pickering Emulsion Gel through Polyphenol-Inspired Free-Radical Grafting of Microcrystalline Cellulose for 3D Food Printing

The manufacture of next-generation 3D-printed foods with personalized requirements can be accelerated by in-depth knowledge of the development of a multifunctional biopolymeric-based ink. As a fat replacer in the food industry, microcrystalline cellulose (MCC) has the potential to address the growing need for sustainable healthy reduced-fat 3D printed foods. The modification of MCC structure by polyphenols gives the way to produce a multifunctional antioxidative Pickering emulsion with improved emulsifying properties. In this study, different types of polyphenols, including gallic acid (GA), tannic acid (TA), and cyanidin-3-O-glucoside (C3G), were individually used to synthesize the grafted MCC-g-polyphenol conjugates by the free-radical grafting method. Then, the antioxidative grafted microconjugates were added to a soy protein-based emulsion gel to partially substitute its oil, and each Pickering emulsion gel variant was printed through an extrusion-based 3D printing system. Emulsifying properties and antioxidant character of MCC were proven to be enhanced after the fabrication of grafted microconjugates. Compared to MCC-g-TA, MCC-g-GA and MCC-g-C3G could efficiently improve the stability of a reduced-fat soy-based emulsion gel upon storage. Moreover, the reduced-fat soy-based emulsion gel containing grafted microconjugates endowed a characteristic shear-thinning behavior with a gel-like structure and superlative thixotropic properties. Following the printing, the antioxidative Pickering emulsion gels containing grafted microconjugates produced well-defined 3D structures with superior lubrication properties. This study demonstrated that the grafting of polyphenols onto MCC could enhance bioactive properties and improve emulsifying performance of MCC, making it a useful component in the development of personalized functional foods.

New insights into food O/W emulsion gels: Strategies of reinforcing mechanical properties and outlook of being applied to food 3D printing

3D printing technology has been widely used in food processing with its advantages of customized food design, personalized nutrition design, and simplified food supply chain. Food emulsion gels have application value and prospects in food 3D printing due to their promising properties, including biodegradability, biocompatibility, as well as dual characteristics of emulsions and biopolymer gels. Food emulsion gels with appropriate mechanical properties, as a new type of food inks, expand the types and functions of the inks. However, food emulsion gels without adequate reinforced mechanical properties may suffer from defects in shape, texture, mouthfeel, and functionality during 3D printing and subsequent applications. Therefore, it is necessary to summarize the strategies to improve the mechanical properties of food emulsion gels. According to the methods of characterizing the mechanical properties of emulsion gels, this article summarizes four strategies for improving the mechanical properties of emulsion gels through two ways: inside-out (reinforcement of interface and reinforcement of cross-linking) and outside-in (physical approaches and environmental regulations), as well as their basic mechanisms. The application status and future research trends of emulsion gels in food 3D printing are finally discussed.