Structural and rheological properties of meat analogues from Haematococcus pluvialis residue-pea protein by high moisture extrusion

Comprehensive review of emerging analytical methods for pea protein structure analysis: Advances and implications for food science over the last five years

This review explores recent advancements in analytical techniques for characterizing pea protein structure. With growing interest in sustainable protein sources, understanding the relationship between pea protein's structure and its functionality has become essential. This review covers a range of methods used to assess the structural properties of pea protein, focusing on the impact of environmental and processing conditions, as well as interactions with other materials, including mid-infrared spectroscopy, fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, scanning electron microscopy, X-ray methods and calorimetric methods. By elucidating these methods, detailed insights into pea protein's structural and conformational properties as well as its dynamics are provided, contributing to enhance their potential applications. Thus, a comprehensive overview of commonly used analytical techniques for pea protein structure characterization in its different organization levels, aiming to offer readers an understanding of these techniques and highlight their relevance in selecting the most suitable method for analyzing complex matrices.

Evaluating the effects of insoluble dietary fibres on pea protein-based extruded meat analogues

Date fruit (Phoenix dactylifera L.) fibre, a by-product from the date syrup industry, is rich in nutrients and has been increasingly explored as a value-added ingredient for industrial applications. This study investigated the incorporation of date dietary fibre (DF) in pea protein isolate (PPI)-based meat analogues (HMMA) using high-moisture extrusion as a structuring technique. The DF amount was varied at five different concentrations: 0, 5, 10, 20 and 30 % w/w. The moisture content of the HMMAs reduced significantly, as fibres could facilitate the binding of free water. As a result, the addition of DF reduced the thermal stability of HMMAs, as shown by the earlier shifting of water evaporation temperature. Rheological results indicated that the elastic properties of HMMAs were lower with 5 to 10 % DF addition, indicating the formation of a brittle network, signified by an increase in hardness and chewiness. The inclusion of 5 to 10 % DF significantly increased the fibrousness of HMMAs, as shown by the increase in the degree of texturization, which was contributed by protein-fibre and fibre-fibre interaction, which bridged the protein network closer. This study shows the potential of DF influencing the fibrous formation in meat analogues produced using PPI as the primary ingredient.

The flavor properties of Amadori rearrangement products and their potentials in flavor replication of plant-based meat analogs: a review

Plant-based meat analogs (PBMAs) are promising substitutes for balancing the global supply and demand of meat products. The urgent necessity of a meat-like flavor becomes prominent owing to the aroma and taste defects of plant-based meat analogs, which restricts the desire for consumption. As significant Maillard reaction intermediates, Amadori rearrangement products (ARPs) are key flavor precursors that contribute to the required flavor compounds and taste properties; flavor replication in PBMAs is expected. The present review aims to discuss the flavor properties of ARPs and their potential and impact on PBMAs flavor replication. The potential impact of ARPs on the flavor profile of PBMAs lies in the interaction between ARPs and fatty acids or peptides. Strategies aimed at improving the flavor formation of ARPs were proposed for further flavor replication of PBMAs, targeting the flavor flaws of PBMAs caused by the ingredients and processing parameters. Additionally, flavor compounds derived from lipid oxidation are indispensable in meat flavor; the construction of animal fat via vegetable oil, the interaction between ARPs and fatty acids, and further regulation strategies are regarded as significant research trends for PBMAs flavor enhancement.

Systematically Investigating the Qualities of Commercial Encapsulated and Industrial-Grade Bulk Fish Oils in the Chinese Market

Fish oil is one of the most popular dietary nutritional supplements. Reports on the qualities of fish oils from Chinese markets are scarce, although the consumption of fish oil products in China is huge and increasing. This study systematically investigated the qualities of commercial encapsulated fish oils (CFs) and bulk fish oils (BFs) from Chinese markets, including oxidative level, sensory quality, color, metal element content, and unsaturated fatty acid content. Significant quality variations were observed both among individual CFs and between BFs: 65.2% of CFs (excluding one flavored sample) and one BF sample met China's Grade II fish oil oxidation product standards; 80.8% of CFs and three BFs were within regulatory limits for heavy metal contamination. A distinct fishy odor was detected in four CFs and one BF sample, while a pronounced rancid odor was observed in one CF sample. The EPA contents in 64% of CFs and DHA contents in 48% of CFs met their labeled claims. Furthermore, these five quality parameter categories demonstrated non-significant intercorrelations, with the fish oil unit price being independent of quality. These findings indicated that most BFs require refinement, and CFs require implementation of low-temperature dark storage/transportation protocols. This study provided comprehensive quality benchmarks for fish oil production and marketing.

Mechanism of Textural Reorganization in Silkworm Chrysalis and Pea Protein Extrusion: Structural Evolution and Quality Characteristic

Mixed extrusion of animal and plant proteins has great potential in meat substitution studies. In this study, we analyzed the mechanism of change in the reorganization of animal and plant proteins during extrusion by exploring the changes in physicochemical properties with different percentages of silkworm chrysalis protein (SCP) additions (3%, 6%, 9%, 12%, 15%) mixed with pea protein isolate (PPI). The results showed that the moderate addition of SCP (12%) reduced the stiffness and denseness of the protein structure of the extrudates, and increased the total amino acid content of the extrudates, up to 74.83. Meanwhile, the addition of SCP changed the rearrangement of the proteins to form new chemical cross-linking bonds with higher bonding energies. Enthalpy of the sample up to 252.6 J/g, enhancing the denaturation energy requirement of the sample. Notably, the addition of SCP weakened the textural properties of the product, resulting in a minimum fibrous degree of 0.88, and improved the overall color of the sample, resulting in an L* value of up to 114.61. Such a change makes the product more suitable for further processing. Scanning electron microscopy (SEM) revealed that the addition of SCP changed the microstructure of the product, resulting in a looser, more porous sample overall. These results systematically elucidate the microscopic mechanisms of SCP and PPI restructuring during high-moisture extrusion.

Alternative Protein-Based Meat and Fish Analogs by Conventional and Novel Processing Technologies: A Systematic Review and Bibliometric Analysis

This study aimed to explore the extent of research on developing meat and fish analogs using alternative proteins. It examined the novel and conventional technologies employed to produce these analogs and identified the primary alternative proteins that were used in their production through a systematic literature review (SLR) using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and bibliometric analysis. The SLR resulted in 46 and 13 meat and fish analog records, respectively, according to defined selection and exclusion criteria. Meat analogs are mainly produced using extrusion, followed by the novel 3D printing and mixing technology. Additionally, fish analogs are mainly produced by mixing and 3D printing. Meat analogs are mainly produced from pulses, followed by cereal, fungi, microalgae, other sources, and insects. Similarly, pulse proteins were the most used alternative protein source for the fish analogs, followed by macro- and microalgae, plant, cereal, and fungal proteins. According to keyword analysis, rheological and textural properties are essential for meat and fish analogs. This review provides up-to-date information to clarify the critical role of alternative proteins and the utilization of novel technologies in the production of meat and fish analogs. It also gives essential insights into the expected increase in studies to determine sustainability and overcome challenges related to textural, sensorial, and nutritional properties.

Effects of soybean insoluble dietary fiber and CaCl2 on the structure and properties of low-moisture extruded products

BACKGROUND

Texturized vegetable protein is currently a leading alternative to animal meat. This study examined the effects of soybean insoluble dietary fiber (SIDF) (0% to 20%) and CaCl2 (0% to 1%) on the structure and properties of extruded products made from a soybean protein isolate-wheat gluten (SPI-WG) composite.

RESULTS

The study showed that SIDF (4% to 8%) increased the viscosity of extruded products, enhanced their specific mechanical energy, and improved their rehydration rate and tensile strength compared with a control group. The rehydration rate of the extruded products reached a maximum value of 331.67% in the 8% SIDF, 0.5% CaCl2 groups. The addition of excess SIDF prevented the cross-linking of protein molecules to form a loose network structure. Analysis of the infrared spectrum and intermolecular forces showed that physical interactions between fibers and proteins were the dominant forces, with hydrophobic interactions and hydrogen bonds primarily maintaining the structure of the extruded products. The addition of CaCl2 (0.5%) led to protein aggregation and further improved the rehydration and tensile strength of extruded products.

CONCLUSION

Soybean insoluble dietary fiber can improve the rehydration rate and quality of extruded products. The addition of CaCl2 mitigated the weakening of the protein structure caused by excess SIDF. These results provide a basis for the improvement of the quality of low-moisture-extruded texturized vegetable protein products with a high dietary fiber concentration and a high rehydration rate. © 2024 Society of Chemical Industry.

Gelling ability and gel structure of soy protein isolate influenced by heating in the presence of various acids

This study investigated the influence of acids on gelation of soy protein isolate (SPI) under heating. Specifically, the SPI solution was acidified to pH 2.5 using hydrochloric acid (HA), acetic acid (AA), tartaric acid (TA) and citric acid (CA), respectively, and then heated at 85 °C. It was found that the SPI gel with the anisotropic structure was formed, which suggested that the gel resulted from the organized arrangement of the SPI fibril. Subsequently, it was confirmed by several techniques such as atomic force microscopy that the above acidic-thermal treatment induced fibrillation of SPI. Furthermore, the ability of these acids to promote gelation and fibrillation of SPI was in the order of CA > TA > HA > AA. In summary, these results suggested that heating at pH 2.5 resulted in SPI fibrillation, thus promoting SPI gelation, and the acidity regulator type had a profound effect.

Development and characterization of fibrous high moisture extrudates based on pea protein isolate and whey protein

BACKGROUND

Construction of meat analogs based on pea protein isolate (PPI) alone by high moisture extrusion (HME) is diffocult as a result of the lack of anisotropic structures. In the present study, 0%-15% of whey protein (WP) was introduced to PPI to make hybrid blends, which were used to construct HME extrudates.

RESULTS

WP enhanced the hardness, adhesive, cohesiveness and gumminess of the extrudates and facilitated the formation of a distinct anisotropic structure of PPI. The fibrous degrees of the extrudates containing 10% and 15% WP were around 1.50. The addition of WP, which has more -SH groups, increased the disulfide bonds and hydrogen bonding in the extrudates, leading to a denser cross-linked structure. Particle size distribution and Fourier transform infrared analysis showed that WP induced more compact structured aggregates and more β-sheet structures in the extrudates. Furthermore, the higher hydration capacity of WP may also help form a dilute melt and generate a more pronounced plug flow, assisting the formation of fiber structures of PPI.

CONCLUSION

The present study demonstrates that WP is a potential modifier, which could be used to improve the structure of PPI-based meat analogs. © 2024 Society of Chemical Industry.

Quality characteristics and fibrous structure formation mechanism of walnut protein and wheat gluten meat analogues during high-moisture extrusion cooking process

Blending two or more materials to create better high-moisture meat analogues has been actively studied in the food science and technology field. Walnut protein is a high-quality plant-based protein resource, yet its full potential remains underexploited. Thus, this study focused on exploring the quality characteristics and fibrous structure formation mechanism of walnut protein (WP) and wheat gluten (WG) meat analogues during high-moisture extrusion cooking process. Results showed that the optimized WP and WG-blended high-moisture meat analogues exhibited a more pronounced anisotropic and oriented fibrous structure. The blending of WP and WG can protect the molecular chains from the thermal transition, and promote the aggregation of protein molecules mainly by enhancing the interaction between hydrophobic interactions and hydrogen bonds, increasing the apparent viscosity and forming protein subunits with larger molecular weights (>100 kDa) to stabilize the newly formed conformation. Additionally, the content of α-helix was the highest among the secondary structures. This study provides a theoretical basis for the application of WG and WP to produce HMMAs with rich fibrous structures.

Binding and distribution regularity of water molecules in high-moisture textured Antarctic krill (Euphausia superba) meat

High-moisture extrusion technique with the advantage of high efficiency and low energy consumption is a promising strategy for processing Antarctic krill meat. Consequently, this study aimed to prepare high-moisture textured Antarctic krill meat (HMTAKM) with a rich fiber structure at different water contents (53 %, 57 %, and 61 %) and to reveal the binding and distribution regularity of water molecules, which is closely related to the fiber structure of HMTAKM and has been less studied. The hydrogen-bond network results indicated the presence of at least two or more types of water molecules with different hydrogen bonds. Increasing the water content of HMTAKM promoted the formation of hydrogen bonds between the water molecules and protein molecules, leading to the transition of the β-sheet to the α-helix. These findings offer a novel viable processing technique for Antarctic krill and a new understanding of the fiber formation of high-moisture textured proteins.

Tenderness in meat and meat alternatives: Structural and processing fundamentals

The demand for meat alternatives based on ingredients sourced from nonanimal materials with equivalent quality of muscle tissue is increasing. As more consumers switch to meat alternatives, a growing body of research has investigated the tenderness and related texture attributes in plant-based meats to increase consumer acceptance. A deeper understanding of tenderness including the differences and similarities between meat and meat alternatives is crucial to developing products that meet consumer expectations, as it directly influences consumer acceptance. Meat tenderness is commonly quantified using sensory evaluation and instrumental tests and is influenced by various factors such as the intrinsic features of the animal before the slaughter, naturally occurring proteolysis during the post-slaughter process, and several tenderization techniques. In contrast, meat alternative tenderness can be actively tailored through the selection of ingredients and the operating conditions of the structuring process. Especially, extrusion parameters such as moisture content and barrel temperature can greatly modulate tenderness-related attributes. Postprocessing methods that have traditionally been utilized for tenderizing have also been applied to meat alternatives, but more studies are needed to fully reveal the underlying mechanisms. This review offers an overview and critical discussion on tenderness, covering the structural origins, influencing factors, analytical methods, oral processing, and tenderization processes for both meat and meat alternatives. The discussion is based on the existing knowledge of muscle tissue, which evolves to critically reviewing how this understanding can be applied to the textural attributes of meat alternatives and what kind of novel tenderization techniques can be developed for these new sustainable food products.

A Review on the Application of Animal-Based Materials Using Three-Dimensional (3D) Printing and Protein Restructuring Technologies

Production of alternative proteins is crucial for the development of future protein resources. This study explored the creation of sustainable animal resources by combining extrusion molding and three-dimensional (3D) printing technologies. Extrusion effectively organizes vegetable proteins at high temperatures and pressures to replicate meat-like textures, and high-moisture extrusion successfully mimics the fiber structure of conventional meat. However, many meat analogs products still differ from conventional meat in terms of sensory properties such as texture, juiciness, and flavor, indicating the need for quality improvement. Researchers have leveraged 3D printing technology to incorporate fat analogs and enhance the appearance and texture through muscle fiber simulation. This technology allows for precise arrangement of muscle fibers, formation of adipose tissue, and marbling, thereby improving the overall sensory experience. By combining extrusion and 3D printing, we can enhance the nutritional and organoleptic qualities of meat analogs, ultimately meeting consumer expectations and achieving a balance between plant- and animal-based materials.

Alaska pollock surimi-based meat analogs by high-moisture extrusion: Effect of konjac glucomannan/curdlan/carrageenan/sodium alginate on fibrous structure formation

This study investigated the effects of the addition of konjac glucomannan (KGM), curdlan (CD), carrageenan (CA), and sodium alginate (SA) on fibrous structure formation in surimi-based meat analogs to livestock meat. Meat analogs were prepared using high-moisture extrusion with Alaskan pollock surimi and soy protein isolate at a ratio of 7:3 (w/w). The meat analogs samples were labeled as SSP. Macrostructure observation showed that the best fibrous structure was obtained in SSP containing 2% SA. Mesostructure and microstructure observations revealed that 2% CD, CA or SA promoted the formation of a less tight three-dimensional network structure, which contributed to the formation of fiber filaments. Increased β-sheet structure content, ordered degree, fractal dimension and thermal stability were observed in SSP with the three colloids. Moreover, fibrous texture was closely associated with the thermal stability and fractal dimension. This study has provided useful information for colloid application in surimi-based meat analogs.

A mechanistic investigation into combined influences of NaCl and extrusion temperature on fibrous structures of high-moisture textured yeast protein

NaCl and extrusion temperature have an important influence on the qualities of high-moisture textured proteins, but the influence mechanism is still unclear. Therefore, this study prepared high-moisture textured yeast protein (HMTYP) with different NaCl contents (0%-4%) under different extrusion temperatures (170 °C, 180 °C) and characterized their physicochemical properties. The results showed that the HMTYP containing 1% and 2% NaCl prepared at 180 °C contained a strong fibrous structure. The possible mechanism was as follows: YP could not be sufficiently melted at 170 °C after adding NaCl, causing a decrease in the structural strength; however, at 180 °C, YP still reached a fully molten state even though 1%-2% NaCl was added. After YP sufficiently melted, NaCl enhanced the cross-linking and aggregation of proteins during cooling, which improved the textural properties of HMTYP. Accordingly, NaCl and extrusion temperature could combine to adjust the fibrous structure and texture of HMTYP.

Use of FTIR to study secondary structure of texturized plant proteins by high moisture extrusion cooking, a comprehensive review

Fourier-Transform Infrared spectroscopy (FTIR) is often used by researchers to understand the texturization mechanisms of plant proteins. High Moisture Extrusion-Cooking (HMEC) is the main process used for their texturization by heating, mechanical shearing, and subsequent cooling of a high-moisture mixture, which causes denaturation and restructuration of proteins, resulting in an anisotropic product, commonly called "meat analog". Researchers try to link the properties of extrudates to the secondary conformation of proteins, which are supposed to aggregate and align in the flow direction within the die. This review will attempt to show the reasons for studying the secondary structures of plant proteins in HMEC-textured products, and compare and discuss the different methods applied to prepare samples and analyze them by FTIR. A focus will be put on the different methods of spectra analysis (i.e., peak deconvolution, and reference tables used), for which a total of around 60 scientific papers have been carefully analyzed to illustrate the disparity of reference tables used in the literature. A discussion will summarize the various hypotheses currently found in the literature, and provided by FTIR to explain the texturization mechanisms of plant proteins through HMEC. Finally, advice such as comparing results with other amide bands and other analysis methods and following published procedures, are provided as an outlook for future improvements in FTIR data quality, processing and interpretation.

Microstructural and textural characteristics of blend gels and high-moisture meat analogs of soy protein isolate and faba bean protein concentrate

In this study, the effects of faba bean protein concentrate (FPC) and soy protein isolate (SPI) on the microstructure and texture of high-moisture meat analogs (HMMA) were extensively analyzed using rheological methodologies. Rheological analyses revealed that introducing FPC disrupted the gel structure and hindered the formation of a protein network among the SPIs. The gel stability also indicated that higher FPC content increased the susceptibility to continuous oscillation, potentially resulting in structural collapse. The β-sheets content decreased from 43.55 % to 37.19 % as the FPC content increased. The observed decline in the textural properties of HMMA, accompanied by microstructural alterations and diminished protein alignment, further supported the hypothesis that FPC disrupts protein network formation. Additionally, as the FPC content increased, the content of disulfide bonds decreased, emphasizing the role of FPC as a texture modulator that affects the rubbery texture of SPI.

Haematococcus pluvialis meets gellan gum: Rheological and thermal exploration of a new resource food and biomedical gel matrix

The increasing interest in hydrogel matrices and their diverse applications has fueled extensive research. However, single-component gels have a limited adjustable performance range, and multi-component gels raise concerns about biological safety, hindering their widespread use. This study focuses on harnessing high-speed shearing and ultrasound-assisted methods to incorporate active natural Haematococcus pluvialis (HP), creating novel composite hydrogels in conjunction with biological macromolecule gellan gum, and eliminating the need for structural modifications or chemical crosslinking. Rich astaxanthin, proteins, polysaccharides, and other components in HP can fill and promote the formation of a unified functional network. The study aims to explore the potential of HP as a rheology regulator and investigate its impact on the rheological properties of the gels. Various rheological models, including Power-Law, Herschel-Bulkley, and Arrhenius, were employed for comparative analysis. This pioneering report on gellan/HP hydrogels holds significant importance as they exhibit optimized elasticity, thermal stability, enhanced injectability, and self-recovery, making them suitable for a wide range of applications in specialized medical food and biomedicine.

Textural improvement of pea protein-based high-moisture extrudates with corn zein and rice starch

High moisture extrusion allows the production of plant protein-based products, including meat analogues. Building upon our previous findings showing that zein mixed with rice starch provides the necessary textural properties to formulations, different pea protein-based formulations with varying amounts of zein and rice starch or wheat gluten (as control) were produced using high moisture extrusion and the rheological, textural, and microstructural characteristics were evaluated and associated with the secondary structure of proteins. Samples containing wheat gluten presented desirable rheological and mechanical properties in terms of texturization, which was evidenced by the generation of a layered and three-dimensional viscoelastic network. The addition of rice starch to zein significantly increased the viscoelasticity of the samples due to enhanced development of non-covalent interactions that led to higher and more stable β-sheets content and to the formation of a fibrous and layered microstructure and a 3D network nearly like those obtained with gluten. The sole replacement of pea protein by zein was not enough to develop these desired characteristics, demonstrating the importance of the non-covalent interactions between rice starch and zein for the generation of these properties. Overall, zein and rice starch improved texturization of pea protein-based gluten-free analogues made by high moisture extrusion.

Leveraging microalgae as a sustainable ingredient for meat analogues

As the world's population and income levels continue to rise, there is a substantial increase in the demand for meat, which poses significant environmental challenges due to large-scale livestock production. This review explores the potential of microalgae as a sustainable protein source for meat analogues. The nutritional composition, functional properties, and environmental advantages of microalgae are analyzed. Additionally, current obstacles to large-scale microalgal food production are addressed, such as strain development, contamination risks, water usage, and downstream processing. The challenges associated with creating meat-like textures and flavors using techniques like extrusion and emulsion formation with microalgae are also examined. Lastly, considerations related to consumer acceptance, marketing, and regulation are summarized. By focusing on improvements in cultivation, structure, sensory attributes, and affordability, microalgae demonstrate promise as a transformative and eco-friendly protein source to enhance the next generation of meat alternatives.

Meat analogue preparation from cricket and rice powder mixtures with controlled textural and nutritional quality by freeze alignment technique

The rising demand for sustainable protein sources has encouraged interest in alternative food products like meat analogues. This study explores formulating meat analogues using cricket powder (CP) and rice flours, comparing them with soy protein-based analogues. CP exhibited a higher soluble protein content (5.9%) than soy protein powder (4.7%), enhancing textural properties by forming fiber-like structures, increasing firmness and adhesion, and reducing chewiness. Despite having a lower water holding capacity (WHC) than soy analogues, all samples outperformed chicken breast WHC. Under freezing conditions, CP and rice flour combinations formed multilayered structures in protein gels. The optimal formulations were CP and sticky rice flour (ratio 6:1) with respect to their texture properties, fiber structure, and nutritional value. This study highlights the potential of cricket powder and rice flour combinations as viable meat analogue ingredients, addressing the need for sustainable protein sources in the food industry.

High-Moisture Extrusion of Plant Proteins: Fundamentals of Texturization and Applications

The growing demand for sustainable and healthy food alternatives has led to a significant increase in interest in plant-based protein products. Among the various techniques used in creating meat analogs, high-moisture extrusion (HME) stands out as a promising technology for developing plant-based protein products that possess desirable texture and mouthfeel. During the extrusion process, plant proteins undergo a state transition, causing their rheological properties to change, thereby influencing the quality of the final extrudates. This review aims to delve into the fundamental aspects of texturizing plant proteins using HME, with a specific focus on the rheological behavior exhibited by these proteins throughout the process. Additionally, the review explores the future of HME from the perspective of novel raw materials and technologies. In summary, the objective of this review is to provide a comprehensive understanding of the potential of HME technology in the development of sustainable and nutritious plant-based protein products.

Next-Generation Plant-Based Foods: Challenges and Opportunities

Owing to environmental, ethical, health, and safety concerns, there has been considerable interest in replacing traditional animal-sourced foods like meat, seafood, egg, and dairy products with next-generation plant-based analogs that accurately mimic their properties. Numerous plant-based foods have already been successfully introduced to the market, but there are still several challenges that must be overcome before they are adopted by more consumers. In this article, we review the current status of the science behind the development of next-generation plant-based foods and highlight areas where further research is needed to improve their quality, increase their variety, and reduce their cost, including improving ingredient performance, developing innovative processing methods, establishing structure-function relationships, and improving nutritional profiles.

The Color-Developing Methods for Cultivated Meat and Meat Analogues: A Mini-Review

Novel meat-inspired products, such as cell-cultivated meat and meat analogues, embrace environmental sustainability, food safety and security, animal welfare, and human health, but consumers are still hesitant to accept these products. The appearance of food is often the most persuasive determinant of purchasing decisions for food. Producing cultivated meat and meat analogues with similar characteristics to conventional meat could lead to increased acceptability, marketability, and profitability. Color is one of the sensorial characteristics that can be improved using color-inducing methods and colorants. Synthetic colorants are cheap and stable, but natural pigments are regarded as safer components for novel food production. The complexity of identifying specific colorants to imitate both raw and cooked meat color lies in the differences in ingredients and methods used to produce meat alternatives. Research devoted to improving the sensorial characteristics of meat analogues has noted various color-inducing methods (e.g., ohmic cooking and pasteurization) and additives (e.g., lactoferrin, laccase, xylose, and pectin). Additionally, considerations toward other meat components, such as fat, can aid in mimicking conventional meat appearance. For instance, the use of plant-based fat replacers and scaffolds can produce a marked sensory enhancement without compromising the sustainability of alternative meats. Moving forward, consumer-relevant sensorial characteristics, such as taste and texture, should be prioritized alongside improving the coloration of meat alternatives.

Utilizing Haematococcus pluvialis to simulate animal meat color in high-moisture meat analogues: Texture quality and color stability

The effect of Haematococcus pluvialis (HP) (0.25∼1.25 %) as a colorant during high moisture extrusion (50 %) on the texture and microstructural properties of soy protein-based high moisture meat analogs (HMMA) was evaluated. Furthermore, the stability of HP-induced meat like color of the HMMA as a function of light exposure, freeze/thawing, frozen storage and cooking temperature and duration was investigated. The addition of HP reduced the elasticity of HMMA but enhanced its hardness, chewiness, and resilience. HP addition at low levels promoted the flexible and disordered regions within the protein secondary structure while excessive HP addition was unfavorable for protein cross-linking. The optimal degree of texturization was achieved with 0.75 % HP. Sensory evaluations revealed that HMMA with 1 %HP had a color similar to fresh beef sirloin, while HMMA with 0.25 % HP had a color closer to fresh pork loin. Light exposure induced the greatest color loss of the meat analogs compared with the cooking and frozen storage. The a* value of HMMA containing 1.25 % HP decreased by 30 % during the 14 days of light exposure. Frozen storage at darkness efficiently preserved the meat-like color of the extrudates. Overall, HP was found as promising colorant for HMMA production but the storage condition of the extrudates should be carefully optimized.

The technical potential of a sous-vide processing method for developing high-moisture textured soy protein

This study explored the potential of sous-vide processing as a novel technique for transforming low-moisture textured soy protein (TSP) into a product with high moisture content and texture comparable to meat. We hypothesized that the sous-vide treatment would enable precise control of the TSP microstructure. In the ensuing process, the TSP maintained the moisture content at approximately 70% and changed color towards darker tones. Additionally, the porous microstructure changed, transitioning from a large to a smaller air layer. As the treatment continued, both the hardness and texturization index of the TSP were reduced. Furthermore, the secondary structure of the protein exhibited an increase in β-sheet and α-helix structures, indicating enhanced hydrogen bonds, hydrophobic interactions, and disulfide bonds. Optimally, a sample with 24 h at 90℃ displayed textural characteristics similar to chicken breast. The investigation underlines the sous-vide method as a revolutionary technique yielding high-moisture content and improved texture for TSP.

The Effect of Type of Vegetable Fat and Addition of Antioxidant Components on the Physicochemical Properties of a Pea-Based Meat Analogue

In recent years, interest in functional foods and meat analogues has increased. This study investigated the effect of the type of vegetable fat and ingredients with antioxidant activity on the properties of a meat analogue based on textured pea protein. The possibility of using acai oil (AO), canola oil (CO) and olive oil (OO); propolis extract (P); buckwheat honey (H); and jalapeno pepper extract (JE) was investigated. The texture, colour and selected chemical parameters of plant-based burgers were analysed. Results showed that burgers from control group had the lowest hardness, while burgers with honey had the highest. The highest MUFA content was found in samples with olive oil. Samples with honey were characterised by the highest content of polyphenols, flavonoids and antioxidant capacity. The highest overall acceptability was observed in burgers from the JE-CO group. Therefore, it is possible to use selected ingredients with antioxidant activity in the recipe for a plant-based burger with high product acceptability.

Effects of the soy protein to wheat gluten ratio on the physicochemical and structural properties of Alaska pollock surimi-based meat analogs by high moisture extrusion

Surimi products have attracted much attention and are widely used in the food industry. Currently, the processing and exploitation of surimi products are mostly based on their gel characteristics. However, the abundant protein in surimi can be rearranged and integrated by high-temperature melting to generate a new surimi product with fibrous structures. In this study, meat analogs (new surimi product) were produced by high moisture extrusion (HME) using Alaska pollock surimi and plant protein (8:2), where the plant protein consisted of different ratios of soy protein and wheat gluten (9:1, 7:3, 5:5, 3:7 and 1:9). The product was marked as SSG because it was composed of Alaska pollock surimi, soy protein and wheat gluten. The structure and color results showed that the hardness and ΔE of SSG decreased, while the fibrous degree and lightness increased with increasing WG content. The observation of the macrostructure and microstructure also showed that the skeleton structure of SSG was more obvious with increasing WG addition, but the viscosity reflected a decreasing trend. Furthermore, an increase in the WG content raised the free water ratio and the total content of β-sheets, whereas the appropriate plant protein ratio reduced the SSG's thermal stability. In conclusion, Alaskan pollock surimi and the appropriate proportion of plant protein can form structurally stable meat analogs by high moisture extrusion.

Yellow Field Pea Protein (Pisum sativum L.): Extraction Technologies, Functionalities, and Applications

Yellow field peas (Pisum sativum L.) hold significant value for producers, researchers, and ingredient manufacturers due to their wealthy composition of protein, starch, and micronutrients. The protein quality in peas is influenced by both intrinsic factors like amino acid composition and spatial conformations and extrinsic factors including growth and processing conditions. The existing literature substantiates that the structural modulation and optimization of functional, organoleptic, and nutritional attributes of pea proteins can be obtained through a combination of chemical, physical, and enzymatic approaches, resulting in superior protein ingredients. This review underscores recent methodologies in pea protein extraction aimed at enhancing yield and functionality for diverse food systems and also delineates existing research gaps related to mitigating off-flavor issues in pea proteins. A comprehensive examination of conventional dry and wet methods is provided, in conjunction with environmentally friendly approaches like ultrafiltration and enzyme-assisted techniques. Additionally, the innovative application of hydrodynamic cavitation technology in protein extraction is explored, focusing on its prospective role in flavor amelioration. This overview offers a nuanced understanding of the advancements in pea protein extraction methods, catering to the interests of varied stakeholders in the field.

Effect of Process Variables and Ingredients on Controlled Protein Network Creation in High-Moisture Plant-Based Meat Alternatives

The market has observed a rapid increase in the demand for plant-based foods as an alternative to animal meat products. Technologies such as high-moisture extrusion (HME) have the potential to develop anisotropic structures using alternative protein ingredients. This article discusses the different possible mechanisms responsible for structure formation and the effect of extrusion process parameters and outlines the recent advances in the long cooling dies (LCDs) used for meat alternative development. The role of different protein ingredients and the impact of combining them with other biopolymers were also evaluated. The underlying mechanism behind anisotropic structure formation during HME is a synergistic effect, with substantial dependence on the source of ingredients and their processing background. Formulation including proteins derived from plants, insects, animals, and microalgae with other biopolymers could pave the way to develop structured meat alternatives and fill nutritional interstices. Dynamic or rotating annular gap cooling dies operating at freely controllable shear and static annular gap dies are recent developments and assist to produce layered or fibrous structures. The complex chemical sites created during the HME of plant protein favour flavour and colour retention. This paper summarises the recent information published in the scientific literature and patents, which could further help researchers to fill the present knowledge gaps.

The potentials and challenges of using fermentation to improve the sensory quality of plant-based meat analogs

Despite the advancements made in improving the quality of plant-based meat substitutes, more work needs to be done to match the texture, appearance, and flavor of real meat. This review aims to cover the sensory quality constraints of plant-based meat analogs and provides fermentation as a sustainable approach to push these boundaries. Plant-based meat analogs have been observed to have weak and soft textural quality, poor mouth feel, an unstable color, and unpleasant and beany flavors in some cases, necessitating the search for efficient novel technologies. A wide range of microorganisms, including bacteria such as Lactobacillus acidophilus and Lactiplantibacillus plantarum, as well as fungi like Fusarium venenatum and Neurospora intermedia, have improved the product texture to mimic fibrous meat structures. Additionally, the chewiness and hardness of the resulting meat analogs have been further improved through the use of Bacillus subtilis. However, excessive fermentation may result in a decrease in the final product's firmness and produce a slimy texture. Similarly, several microbial metabolites can mimic the color and flavor of meat, with some concerns. It appears that fermentation is a promising approach to modulating the sensory profiles of plant-derived meat ingredients without adverse consequences. In addition, the technology of starter cultures can be optimized and introduced as a new strategy to enhance the organoleptic properties of plant-based meat while still meeting the needs of an expanding and sustainable economy.

Study on the Function of Conveying, Kneading Block and Reversing Elements on the Mixing Efficiency and Dispersion Effect inside the Barrel of an Extruder with Numerical Simulation

In order to better understand the extrusion process mechanism of plant protein inside a barrel, the parameter changes and flow characteristics of fluids under conveying, kneading block and reversing elements were investigated with numerical simulation. The results showed that the shear rate increased obviously with the increase in pitch; the shear rate value of the reversing element was larger, while that of the kneading block was the opposite. The screw combinations of conveying, kneading blocks and reversing elements all have a certain degree of mixing effect on the particles, and the reduction in pitch can effectively increase the mixing effect of the particles. The conveying element can provide a relatively constant acceleration for the particles, due to the pumping capability and pressure buildup as the pitch increases. The kneading block and the reversing element can increase the leakage flow between the discs and backflow, resulting in an extension of the residence time distribution that facilitates fluid interaction in the barrel and improves the dispersion of the particles. The restraint by the reversing element on the particles is obviously weaker than that of the kneading block and shows a higher particle mixing degree. Overall, the influence of different elements on the flow condition, mixing degree and residence time is significantly different, which improves the process controllability and provides references for potential applications to meet multiple demands.

Significance of Fermentation in Plant-Based Meat Analogs: A Critical Review of Nutrition, and Safety-Related Aspects

Plant-based meat analogs have been shown to cause less harm for both human health and the environment compared to real meat, especially processed meat. However, the intense pressure to enhance the sensory qualities of plant-based meat alternatives has caused their nutritional and safety aspects to be overlooked. This paper reviews our current understanding of the nutrition and safety behind plant-based meat alternatives, proposing fermentation as a potential way of overcoming limitations in these aspects. Plant protein blends, fortification, and preservatives have been the main methods for enhancing the nutritional content and stability of plant-based meat alternatives, but concerns that include safety, nutrient deficiencies, low digestibility, high allergenicity, and high costs have been raised in their use. Fermentation with microorganisms such as Bacillus subtilis, Lactiplantibacillus plantarum, Neurospora intermedia, and Rhizopus oryzae improves digestibility and reduces allergenicity and antinutritive factors more effectively. At the same time, microbial metabolites can boost the final product's safety, nutrition, and sensory quality, although some concerns regarding their toxicity remain. Designing a single starter culture or microbial consortium for plant-based meat alternatives can be a novel solution for advancing the health benefits of the final product while still fulfilling the demands of an expanding and sustainable economy.

Conformational changes and physicochemical attributes of texturized pea protein isolate-konjac gum: With a new perspective of residence time during extrusion

The present study aimed to investigate the effects of different extrusion temperatures (110, 130 and 150 °C) and konjac gum addition (0.1 %, 0.2 %, and 0.3 %) on the flow behavior, physicochemical properties and microstructure of extruded pea protein isolate (PPI). The results showed that the textured protein could be improved by enhancing the extrusion temperature and adding konjac gum during extrusion. The water/oil holding capacity of PPI decreased and the SH content increased after extrusion. With temperature and konjac gum content increased, the β-sheet of extruded proteins transformed to other secondary structural components, and Trp residue transformed to a more polar environment, illustrating the changes in protein conformation. All extruded samples presented as yellow hue with little green and higher lightness, while excessive extrusion process reduced the brightness and promoted more formation of browning pigments. Extruded protein showed more associated layered with some air pores, and its hardness and chewiness increased with the increase of temperature and konjac gum concentration. Cluster analysis showed that the addition of konjac gum could effectively improve the quality characteristics of pea protein under low temperature extrusion, and the effect was similar to that of high temperature extrusion product. With the increase of konjac gum concentration, the flow pattern of protein extrusion gradually converted from plug flow to mixing flow, and the disorder degree of polysaccharide protein mixing system was enhanced. Moreover, Yeh-jaw model showed better fitting effect in F(θ) curves compared to Wolf-white.

High-moisture extrusion cooking on soybean-wheat protein mixtures: Effect of sodium alginate/xanthan gum/maltodextrin on promoting a fibrous structure

At present, the changes in fibrous structure of plant proteins improved by polysaccharides during high-moisture extrusion cooking (HMEC) are still unclear. In this study, different additions (1, 2, 3, 4, and 5%) of sodium alginate (SA), xanthan gum (XG), and maltodextrin (MD) were used in the preparation of organised protein products based on soybean protein and wheat protein under high moisture extrusion conditions. It was revealed that SA-4%, XG-2%, and MD-2% (w/w) significantly enhanced the structural and physical properties of the fibres. The polysaccharides increased the water distribution of extrudates by enhancing protein-water interactions through hydrogen bonding, with MD-2% having the strongest ability to trap free water. The mechanism by which the polysaccharides improved the fibrous structure of extrudates involved the reorganization of molten proteins from the die head region to the cooling region, formation of new molecular bonds and enhancement of thermal stability. XG-2% significantly increased the β-sheet structure in the molten region (48.9 ± 1.35%) and showed the best thermal stability. Overall, SA-4% was able to better maintain the molecular bonding transformation and strong water absorption, which stabilised the protein conformation and formed the highest fibrous degree (2.1 ± 0.03). This suggests that the properties of the three polysaccharides can be used as modifiers of high water extruded plant proteins to improve the extruded materiality, functional and nutritional properties.

High-moisture extrusion of yeast-pea protein: Effects of different formulations on the fibrous structure formation

The demand of meat analogues (MAs) is consistently increasing. The protein materials for MAs are primarily soy, pea, and wheat protein which can not completely meet the growing demand. Hence, this study is focused on the preparation of MAs with up to 50 % yeast protein (YP) instead of pea protein isolate (PPI). In the present study, 0 %, 10 %, 30 %, and 50 % YP powder in dry matter basis were combined with PPI; then the mixtures were used to prepare MAs with fibrous structures using high-moisture extrusion (55 % moisture). The involvement of YP significantly enhanced the hardness of MAs (P < 0.05). The optical and microstructural images illustrated that when YP ratio reached 30 %, obvious fibrous structures still were observed in MAs. Furthermore, MAs containing YP became whiter, which is conducive to reprocessing. With an increase in YP, the bound water content, sheet structures, and exposure of tryptophan residues in MAs increased, whereas the free water content, β-turn, and random coil structures decreased. Analysis of thermal and rheological behaviors indicated that YP lowered the denaturation temperature of MAs and the viscosity of protein dispersions, which was related to the formation of protein aggregates. Overall, YP can be used to prepare MAs and regulate the fibrous structure in MAs by acting on protein conformations.

Characterization of Tenebrio molitor Larvae Protein Preparations Obtained by Different Extraction Approaches

Edible insects have recently attracted research attention due to their nutritional value and low environmental footprint. Tenebrio molitor larva was the first insect species to be classified by European Food Safety Authority (EFSA) as safe for human consumption. However, it is thought that the incorporation of edible insect as an ingredient in a food product would be more appealing to consumers than being visible. The aim of the present study was to determine the physicochemical properties of the larvae meal and protein concentrates. Different methods to extract and recover proteins from defatted (DF) Tenebrio molitor larvae were applied; i.e., alkaline extraction (DF-ASP); isoelectric precipitation after alkaline extraction (DF-AIP); and NaCl treatment (DF-SSP), and the obtained protein fractions were characterized. The DF-ASP exhibited the highest protein extraction/recovery efficiency (>60%), while it was the most effective in decreasing the interfacial tension at the oil/water (o/w) interface. The DF-AIP had the highest protein content (75.1%) and absolute values of ζ-potential and the best ability to retain water (10.54 g/g) and stabilize emulsions at pH 3.0. The DF-SSP protein preparation had the highest oil binding capacity (8.62%) and solubility (~88%) at acidic pHs and the highest emulsifying activity (~86 m2/g). Electrophoresis of the protein preparations revealed proteins with different molecular weights, while the protein secondary structure was dominated by β-structures and α-helix. Protein concentrates with different properties were able to be recovered from Tenebrio molitor larvae, that could affect their interactions with other food ingredients and their behavior during processing or storage. These findings would be valuable guidance for the technological exploitation of larvae protein preparations in the development of food formulations.

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.

Physicochemical Characteristics and Flavor Properties of Texturized Dual-Proteins Extrudates: Effect of Surimi to Soybean Flour Ratio

This study investigated the effects of surimi to soybean flour ratio (0:10, 1:9, 2:8, 3:7, 4:6) on the physicochemical characteristics and flavor properties of dual-proteins extrudates. The increasing ratio of surimi improved the color of extrudates and raised the apparent viscosity of the mixed raw materials, which led to the decrease of extrudates' thickness. The excess ratio of surimi and soybean flour (more than 2:8) was bad for extrudates' physicochemical characteristics with sharply decreased tensile strength, macroscopic longitudinal fracture, broken and unevenly distributed microstructure, increased water mobility and decreased free water content. However, the increasing ratio of surimi had no effect on the protein secondary structure of extrudates. Sensory evaluation, E-tongue and E-nose analysis suggested that adding surimi significantly changed the flavor properties of extrudates, with increased sweetness and umami taste, and an appropriate ratio (2:8 or 3:7) could reduce the beany flavor and without an obvious fishy off-flavor.

Food extrusion: An advanced process for innovation and novel product development

Extrusion is a versatile process capable of producing a variety of new and novel foods and ingredients, thus increasing manufacturing opportunities. Further, it could provide nutritious, safe, sustainable, and affordable foods, especially directed at individualized consumer needs. In addition to past research efforts, more investigations should be conducted in order to refine, redesign, or develop new extrusion processing technologies. The present review highlights the current advances made in new and novel food product development by considering the extrusion process, the influencing parameters, and product characteristics and properties; the most promising extrusion processes that can be used in novel food product and ingredient development, such as extrusion cooking, hot-melt extrusion, reactive extrusion, and extrusion-based 3D printing; the possibilities of using various raw materials in relation to process and product development; and the needs for product development modeling along with extrusion process design and modeling. In correlation with extruded product development, topics that merit further investigation may include structure formation, plant and animal biopolymers functionalization, biopolymer reactions, process simulation, modeling and control, engineering and mechanical aspects of extruders, analysis of pre-processing treatments, as well as prototyping, risk analysis, safety, sensory and consumer acceptance.

Plant-Based Meat Analogues from Alternative Protein: A Systematic Literature Review

This study aimed to conduct a systematic literature review (SLR) of the research performed in the plant-based meat analogues area. Historical, current, and future tendencies are discussed. The paper offers a comprehensive SLR coupled with a bibliometric analysis of the publication from 1972 to January 2022. The articles were obtained using a research string and precise inclusion and exclusion criteria from two prominent databases, Scopus and Web of Science (WoS). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow technique was used to describe the data screening and selection. In total, 84 publications were selected for further analysis after a thorough literature assessment. From this study, six main themes were identified: (1) objectives of the study; (2) type of plant protein; (3) product type; (4) added ingredients; (5) texturization technique; and (6) quality assessment considered in the studies. Recent trends in publication imply that meat analogue technology is gaining prominence. This review revealed significant research on improving meat analogues via texturization. Even though extrusion is used industrially, the technique is still in its infancy and needs improvement. Future studies should focus more on fiber and protein-protein interactions, macromolecule conformation and mechanisms, diversifying or improving current methods, sensory attributes, and gastrointestinal absorption rate of each novel protein ingredient.

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.