Protein Structure and Network Orientation in Edible Films Prepared by Spinning Process

Exploring the Role and Functionality of Ingredients in Plant-Based Meat Analogue Burgers: A Comprehensive Review

The development of plant-based meat analogues has become a significant challenge for the food industry in recent years due to the increasing demand for sustainable and healthier proteins in the context of a global protein transition. Plant-based meat analogues imitate the visual, textural, and chemical properties of traditional meat products and are required to closely resemble meat to appeal to consumers. In addition, consumers demand natural, clean-label, and nutritional, and healthy products. To address these challenges, the food industry must develop highly healthy, nutritious, and E-number-free meat analogue products. Understanding the functionality of each ingredient and its role in the food matrix is crucial to being a key player in the innovation of the meat analogue market. This review provides updated information on the primary ingredients utilized for the development of plant-based burger meat alternatives and their functionality. The key components of meat analogue burgers are outlined, including plant proteins, binding agents, fats and oils, flavorings, colorings, preservatives, fortificants, and clean-label considerations.

From Fundamental Amyloid Protein Self-Assembly to Development of Bioplastics

Proteins can self-assemble into a range of nanostructures as a result of molecular interactions. Amyloid nanofibrils, as one of them, were first discovered with regard to the relevance of neurodegenerative diseases but now have been exploited as building blocks to generate multiscale materials with designed functions for versatile applications. This review interconnects the mechanism of amyloid fibrillation, the current approaches to synthesizing amyloid protein-based materials, and the application in bioplastic development. We focus on the fundamental structures of self-assembled amyloid fibrils and how external factors can affect protein aggregation to optimize the process. Protein self-assembly is essentially the autonomous congregation of smaller protein units into larger, organized structures. Since the properties of the self-assembly can be manipulated by changing intrinsic factors and external conditions, protein self-assembly serves as an excellent building block for bioplastic development. Building on these principles, general processing methods and pathways from raw protein sources to mature state materials are proposed, providing a guide for the development of large-scale production. Additionally, this review discusses the diverse properties of protein-based amyloid nanofibrils and how they can be utilized as bioplastics. The economic feasibility of the protein bioplastics is also compared to conventional plastics in large-scale production scenarios, supporting their potential as sustainable bioplastics for future applications.

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.

A Critical review focusing the effect of ingredients on the textural properties of plant-based meat products

Plant-based meat alternatives have been studied for decades, but have recently gained more attraction in the food industries and research communities. Concern about animal welfare, health, environment and moral beliefs acts as a driving force for the growth of plant-based meat products. The most challenging task in the development of meat analog is to imitate the texture of conventional meat products. The fabrication of plant-based meat product requires a wise selection and formulation of ingredients to perfectly mimic the fibrous structure of meat. Top-down and bottom-up approaches are the two most commonly used structuring techniques for the preparation of plant-based meat products. Development of comminuted meat product is easy as compared to the whole-muscle type plant-based meat products. Several plant-based ingredients such as texturized and non-texturized proteins, fats, binding agents, flavoring and coloring agents accompanied with different processing techniques (extrusion, shear cell, wet spinning, electrospinning, and freeze structuring) are used in the preparation of meat analogs. This paper aims to discuss the impact of ingredients on the textural properties of plant-based meat products.

Plant protein-based fibers: Fabrication, characterization, and potential food applications

Proteins from plants have been considered as safer, healthier, and more sustainable resources than their animal counterparts. However, incomplete amino acid composition and relatively poor functionality limit their applications in foods. Structuring plant proteins to fibrous architectures enhances their physicochemical properties, which can favor various food applications. This review primarily focuses on fabrication of fibers from plant proteins via self-assembly, electrospinning, solution blow spinning, wet spinning, and high-temperature shear, as well as on several applications where such fibrous proteins assemble in quality foods. The changes of protein structure and protein-protein interactions during fiber production are discussed in detail, along with the effects of fabrication conditions and protein sources on the morphology and function of the fibers. Self-assembly requires proteolysis and subsequent peptide aggregation under specific conditions, which can be influenced by pH, salt and protein type. The spinning strategy is more scalable and produces uniformed fibers with larger length scales suitable for encapsulation, food packaging and sensor substrates. Significant progress has been made on high-temperature shear (including extrusion)-induced fibers responsible for desirable texture in meat analogues. Structuring plant proteins adds values for broadened food applications, but it remains challenging to keep processes cost-effective and environmentally friendly using food grade solvents.

Integrating biomaterials and food biopolymers for cultured meat production

Cultured meat has recently achieved mainstream prominence due to the emergence of societal and industrial interest. In contrast to animal-based production of traditional meat, the cultured meat approach entails laboratory cultivation of engineered muscle tissue. However, bioengineers have hitherto engineered tissues to fulfil biomedical endpoints, and have had limited experience in engineering muscle tissue for its post-mortem traits, which broadly govern consumer definitions of meat quality. Furthermore, existing tissue engineering approaches face fundamental challenges in technical feasibility and industrial scalability for cultured meat production. This review discusses how animal-based meat production variables influence meat properties at both the molecular and functional level, and whether current cultured meat approaches recapitulate these properties. In addition, this review considers how conventional meat producers employ exogenous biopolymer-based meat ingredients and processing techniques to mimic desirable meat properties in meat products. Finally, current biomaterial strategies for engineering muscle and adipose tissue are surveyed in the context of emerging constraints that pertain to cultured meat production, such as edibility, sustainability and scalability, and potential areas for integrating biomaterials and food biopolymer approaches to address these constraints are discussed. STATEMENT OF SIGNIFICANCE: Laboratory-grown or cultured meat has gained increasing interest from industry and the public, but currently faces significant impediment to market feasibility. This is due to fundamental knowledge gaps in producing realistic meat tissues via conventional tissue engineering approaches, as well as translational challenges in scaling up these approaches in an efficient, sustainable and high-volume manner. By defining the molecular basis for desirable meat quality attributes, such as taste and texture, and introducing the fundamental roles of food biopolymers in mimicking these properties in conventional meat products, this review aims to bridge the historically disparate fields of meat science and biomaterials engineering in order to inspire potentially synergistic strategies that address some of these challenges.

Effect of Homogenization at a Lower Pressure on Structural and Functional Properties of Soy Protein Isolate

In this paper, the effects of homogenization at low pressure (1~40 MPa) on structural and functional properties of soy protein isolates (SPI) are investigated. Homogenization at low pressure increase solubility, surface hydrophobicity, emulsification activity and foaming capacity of SPIs, these all functional properties increases and then decreases with the homogenization pressure. Whereas, emulsion stability and foaming stability of SPIs treated by homogenization initially decrease and then increase with homogenization pressure. There is a dramatic decrease in hardness, springiness and cohesiveness of homogenized SPI gels. Generally, homogenization at low pressure do not change the subunit composition of SPIs. It is observed that, when the homogenization pressure is lower than 10 MPa than there is no significant impact on structural change. The content of β-sheet decreased, while unordered structure significantly increased, when the homogenization pressure increased from 10 MPa to 20 MPa. Furthermore, the content of β-sheet increases, when the content of the other structures decreases with the increasing homogenization pressure. The maximum emission wavelength (λmax) for SPIs increases with homogenization pressure increases from 10 Mpa to 20 Mpa, which is attributed to the gradual structural unfolding exposing more hydrophobic residues in protein surface. While, the decreased λmax of SPIs treated with 20 Mpa to 40 Mpa homogenization corresponds to the protein aggregation. It can be deduced that appropriate selection of homogenization pressure is important for improving the functional properties of SPIs.

A review of research on plant-based meat alternatives: Driving forces, history, manufacturing, and consumer attitudes

The topic of plant-based meat alternatives (PBMAs) has been discussed for several decades, but it has only recently become one of the hottest topics in the food and research communities. With the purpose of investigating the current situation of scientific research on PBMA and determining future research opportunities, the driving forces for PBMA development, a brief history of its progression, key technologies required for production, and the resulting consumer attitudes are summarized. Environmental, human health, and animal welfare concerns are the main factors that have driven the development of PBMA. Although its history can trace back to ancient Asian civilizations, the first generation of PBMA originated in 1960s and a new generation of PBMA designed for carnivore was developed in recently years. Structuring methods such as extrusion and shear cell techniques have been widely studied, but improvements toward the overall appearance and flavor, biological and chemical safety control, as well as the selection of protein sources are also very important for PBMA production. The consumer acceptance of PBMA remains unsatisfactory but is continually improving. Based on those knowledge, future research opportunities include developing more effective strategies for consumer education, providing more scientific evidence for the health properties of PBMA, finding more suitable protein sources to improve the quality of the final products, improving the appearance and flavor, further examining and securing the chemical safety, exploring the structure formation mechanism during the extraction or shearing processes, and developing methods and standards for a quality evaluation of PBMA.

Application of Protein-Based Films and Coatings for Food Packaging: A Review

As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.

Improvement of nutritional quality of soybean meal by Fe(II)-assisted acetic acid treatment

We investigated the effect of Fe(II)-assisted acetic acid treatment on improvement of nutrition quality of soybean meal (SBM) by degrading antinutritional factors (ANFs) and maintaining initial nutrition quality. Fe(II)-assistance reduced trypsin inhibitor (TI) content significantly from 5.20 to 0.86 mg/g, and allergenic proteins were completely degraded at 55 °C, due to changes in the conformation of soybean protein isolate (SPI) that renders proteins more prone to acetic acid-mediated degradation. The red-shift of maximum emission wavelength indicated that Fe(II)-assisted acid induced molecular unfolding of SPI and increased surface hydrophobicity. Investigation of protein secondary structure revealed that Fe(II)-assisted acid treatment decreased the β-sheet structure by 4.65% and increased the α-helical content by 7.37%. This demonstrated that Fe(II) and acetic acid synergistically degrade ANFs by altering protein conformations in SBM.

Secondary Structure and Subunit Composition of Soy Protein In Vitro Digested by Pepsin and Its Relation with Digestibility

In the present study, in vitro digestibility and structure of soybean protein isolates (SPIs) prepared from five soybean varieties were investigated in simulated gastric fluid (SGF), using FT-IR microspectroscopy and SDS-PAGE. The result indicated that β-conformations were prone to be hydrolyzed by pepsin preferentially and transformed to unordered structure during in vitro digestion, followed by the digestion of α-helix and unordered structure. A negative linear correlation coefficient was found between the β-conformation contents of five SPIs and their in vitro digestibility values. The intensities of the protein bands corresponding to 7S and 11S fractions were decreased and many peptide bands appeared at 11~15 kDa during enzymatic hydrolysis. β-conglycinin was poorly hydrolyzed with pepsin, especially the β-7S subunit. On the other hand, basic polypeptides of glycinin degraded slower than acidic polypeptides and represented a large proportion of the residual protein after digestion. 11S-A₃ of all SPIs disappeared after 1 h digestion. Moreover, a significant negative linear correlation coefficient (r = −0.89) was found between the β-7S contents of five SPIs and their in vitro digestibility values. These results are useful for further studies of the functional properties and bioactive properties of these varieties and laid theoretical foundations for the development of the specific functional soy protein isolate.

Relationship between Secondary Structure and Surface Hydrophobicity of Soybean Protein Isolate Subjected to Heat Treatment

This study investigated relationship between secondary structure and surface hydrophobicity of soy protein isolate (SPI) subjected to a thermal treatment at 70~90°C. Heat denaturation increased the surface hydrophobicity and surface hydrophobicity decreased as aggregate formed. Heat caused an increase in the relative amount ofα-helix structures and an overall decrease in the amount ofβ-sheet structures when compared with nontreated SPI. The relative amounts of secondary structures varied with time, temperature, and intensity of heat treatment applied. Theβ-sheet structure was most important for its significant role in denaturation of 7S globulin and following formed aggregates and even in denaturation of 11S globulin. The amount ofβ-sheet structure in SPI had an inverse correlation with the surface hydrophobicity when the temperature was kept below 90°C. Besides,β-turn structure increased asβ-7S/B-11S aggregate formated.

Novel soy protein wound dressings with controlled antibiotic release: mechanical and physical properties

Naturally derived materials are becoming widely used in the biomedical field. Soy protein has advantages over various types of natural proteins employed for biomedical applications due to its low price, non-animal origin and relatively long storage time and stability. In the current study soy protein isolate (SPI) was investigated as a matrix for wound dressing applications. The antibiotic drug gentamicin was incorporated into the matrix for local controlled release and, thus, protection against bacterial infection. Homogeneous yellowish films were cast from aqueous solutions. After cross-linking they combined high tensile strength and Young's modulus with the desired ductility. The plasticizer type, cross-linking agent and method of cross-linking were found to strongly affect the tensile properties of the SPI films. Selected SPI films were tested for relevant physical properties and the gentamicin release profile. The cross-linking method affected the degree of water uptake and the weight loss profile. The water vapor transmission rate of the films was in the desired range for wound dressings (∼2300 g m(-2) day(-1)) and was not affected by the cross-linking method. The gentamicin release profile exhibited a moderate burst effect followed by a decreasing release rate which was maintained for at least 4 weeks. Diffusion was the dominant release mechanism of gentamicin from cross-linked SPI films. Appropriate selection of the process parameters yielded SPI wound dressings with the desired mechanical and physical properties and drug release behavior to protect against bacterial infection. These unique structures are thus potentially useful as burn and ulcer dressings.

Formation of Fibrous Materials from Dense Calcium Caseinate Dispersions

Application of shear and cross-linking enzyme transglutaminase (Tgase) induced fibrous hierarchical structures in dense (30% w/w) calcium caseinate (Ca-caseinate) dispersions. Using Tgase was essential for the anisotropic structure formation. The fibrous materials showed anisotropy on both micro- and macroscale as determined with scanning electron microscopy (SEM) and mechanical analyses, respectively. SEM revealed protein fibers with a diameter of approximately 100-200 nm; visually, we observed fibers of about 1 mm. Both shear and Tgase affected the reinforcement of the fibers to a large extent, whereas the mechanical properties in the direction perpendicular to the shear flow remained constant. Shearing Ca-caseinate without Tgase yielded a slightly anisotropic layered structure. Both cross-linking in the absence of shear and cross-linking during mixing resulted in gels without alignment. The formation of shear- and enzyme-induced anisotropic structures was explained by aligning of protein aggregates due to shear and concurrent solidification of the aligned protein aggregates.

Probing structural features of water-insoluble proteins by front-face fluorescence

Front-face fluorescence was used to assess some structural features of proteins in wheat flours, taking advantage of the fact that this technique allowed a direct approach to a number of systems in which most proteins cannot be solubilized without using conditions that strongly modify the structure of proteins in the original material. In this study, we addressed structural changes ensuing from solvation and from mechanical deformation of proteins in wheat flour. Solvation of proteins in the systems under investigation was monitored by taking fluorescence emission spectra of the protein tryptophans (or of protein-bound 1,8-anilino-naphthalene-sulfonate added in appropriate amounts) in mixtures of increasing water content. In separate experiments, changes in overall protein surface hydrophobicity were estimated by titrating flours-mixed with appropriate amounts of water to a dough-like consistency-with increasing concentrations of the fluorescent hydrophobic probe, 1,8-anilino-naphthalene-sulfonate. This approach allowed concomitant determination of the overall binding capacity and of the apparent affinity for the probe of proteins. To test the usefulness of the structural information obtained from these approaches, they were also applied to characterize dough at different levels of mechanical stress, prepared from either wheat flour or semolina.