Methods for Testing the Quality Attributes of Plant-Based Foods: Meat- and Processed-Meat Analogs

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.

The impact of temperature gradient, apparent shear rate, and inferred phase transition timing on extruded high moisture meat analog quality

Scalability of the cooling die unit operation is critical to lowering the manufacturing cost of high moisture meat analogs(HMMA), but it is unclear what scale-up criteria are important. An experiment consisting of two cooling die cross-section geometries (tall and narrow or short and wide), two production rates (2.7 or 4.5 kg/hr) and 4 cooling media inlet temperatures (36, 48, 60, and 72 °C) was employed to study their effect on product texture, anisotropy, and extrusion system parameters. Comprehensive temperature measurements were made along the dies to observe the product temperature gradient and to quantify the energy balance associated with cooling. It was found that textural hardness had a positive relationship with axial temperature gradient (p < 0.05), while anisotropy had a negative and positive relationship with axial temperature gradient and die height, respectively (p < 0.05). Extruder motor torque and die inlet pressure were found to be functions of the cooling media inlet temperature and apparent Newtonian shear rate applied to the material in the die (p < 0.05). The energy balance indicated that enhanced anisotropy is associated with more exothermic in-situ phase changes, which are controlled by the product formulation and applied die conditions. There are likely 3 scalable variables most relevant to controlling the HMMA product quality: 2 critical phase transition temperatures, and the axial product temperature gradient. Therefore, scaling up HMMA cooling dies will require balancing the heat transfer rate away from the product such that an optimal product temperature profile can be maintained at scale.

Impact of functional dietary fiber incorporation on the appearance and mechanical properties of extruded high moisture meat analogs

The effect of including functional dietary fiber ingredients (FDFI) on the texture and structure of high moisture meat analog (HMMA) was examined in this study. The inclusion of FDFI in this application is hypothesized to act as a label-friendly texture modifier in HMMA while also boosting the product's dietary fiber content. Two inclusion rates (5% and 10% wt/wt) of four functionally unique FDFI ingredients (pea hull, citrus fiber, hydrocolloid oat bran, and powdered cellulose) were blended with wheat protein isolate. Each unique formulation was processed using a high-moisture twin-screw extrusion process at two different screw speeds (200 and 400 rpm). The type of FDFI added affected the mechanical texture attributes (hardness, springiness, cohesiveness, and integrity index) and in-process behavior (torque and pressure) of the resulting HMMA far more than the inclusion rate or screw speed (p > 0.05). The type of FDFI ingredient employed also had the largest qualitative effect on the visual appearance of the resulting HMMA. These observed quality changes correlated well with the physicochemical and structure-function properties of the FDFI ingredients, especially with water-holding and absorption capacities. The incorporation of FDFI is a viable means of modulating HMMA texture and improving the holistic nutrition of these products. PRACTICAL APPLICATION: Adding highly functional, dietary fiber-rich ingredients to processed foods is a viable strategy for improving the nutritional and textural quality of these foods. The results of this study imply that these fibers can be added to meat analogs at nutritionally relevant rates, and the texture of the resulting product can be tailored based on the functional properties of the ingredients deployed.

Plant-based fascia tissues: Exploring materials and techniques for realistic simulation

The growing demand for sustainable and ethical food options has led to significant advancements in plant-based meat substitutes (PBMS). PBMS have made considerable progress in simulating the taste, texture, and sensory properties of animal meat. Connective tissue is a fundamental component of animal meat that significantly influences tenderness, texture, and sensory properties. However, the imitation of realistic connective tissues has received relatively less attention in the PBMS industry. The current work focuses on exploring materials and techniques for the replication of plant-based connective tissues (PBCT). By understanding the structural and functional characteristics of animal connective tissues (ACT), it is possible to replicate these characteristics in PBCT. Hydrogels, with their ability to simulate certain properties of ACT, present a viable material for the creation of PBCT. To achieve the desired simulation, their mechanical and structural properties need to be enhanced by using several materials and several physical techniques.

Cold plasma: A success road to mycotoxins mitigation and food value edition

Mycotoxins are common in many agricultural products and may harm both animals and humans. Dietary mycotoxins are reduced via physical, chemical, and thermal decontamination methods. Chemical residues are left behind after physical and chemical treatments that decrease food quality. Since mycotoxins are heat-resistant, heat treatments do not completely eradicate them. Cold plasma therapy increases food safety and shelf life. Cold plasma-generated chemical species may kill bacteria quickly at room temperature while leaving no chemical residues. This research explains how cold plasma combats mold and mycotoxins to guarantee food safety and quality. Fungal cells are damaged and killed by cold plasma species. Mycotoxins are also chemically broken down by the species, making the breakdown products safer. According to a preliminary cold plasma study, plasma may enhance food shelf life and quality. The antifungal and antimycotoxin properties of cold plasma benefit fresh produce, agricultural commodities, nuts, peppers, herbs, dried meat, and fish.

Optimizing Screw Speed and Barrel Temperature for Textural and Nutritional Improvement of Soy-Based High-Moisture Extrudates

Soy remains the legume protein of excellence for plant-based meat alternatives due to its fiber-forming potential. In this study, protein-rich powders from soy protein isolate (SPI), concentrate (SPC), and their mixture (SPM) were thoroughly characterized for their proximate composition, nutritional quality, and physicochemical properties to understand their structuring behavior during high-moisture extrusion. SPI presented higher degrees of protein denaturation and aggregation, least gelation concentration and lower essential amino acid contents. Thus, an SPI:SPC combination (1:9 ratio, 70% protein) was extruded at three different screw speeds (300, 350, and 400 rpm) and two temperature profiles (120 and 140 °C maximum temperature). The effects of the processing parameters on the extrudates were evaluated for their appearance (fibrousness), texture (TPA, cutting force, and anisotropy), color, protein structure (FTIR), and trypsin inhibitors. Higher temperatures resulted in softer and darker extrudates, with increased visual and instrumental anisotropy. Increasing screw speeds led to softer and lighter extrudates, without a clear fibrousness effect. β-sheet structures decreased and intermolecular aggregates (A1) increased after extrusion, especially at 140 °C, together with the formation of intramolecular aggregates (A2). Extrusion also significantly decreased the amount of trypsin inhibitors (>90%). This study demonstrates that extrusion parameters need to be carefully selected to achieve meat analogs with optimal textural and nutritional characteristics.

Novel animal product substitutes: A new category of plant-based alternatives to meat, seafood, egg, and dairy products

Many consumers are adopting plant-centric diets to address the adverse effects of livestock production on the environment, health, and animal welfare. Processed plant-based foods, including animal product analogs (such as meat, seafood, egg, or dairy analogs) and traditional animal product substitutes (such as tofu, seitan, or tempeh), may not be desirable to a broad spectrum of consumers. This article introduces a new category of plant-based foods specifically designed to overcome the limitations of current animal product analogs and substitutes: novel animal product substitutes (NAPS). NAPS are designed to contain high levels of nutrients to be encouraged (such as proteins, omega-3 fatty acids, dietary fibers, vitamins, and minerals) and low levels of nutrients to be discouraged (such as salt, sugar, and saturated fat). Moreover, they may be designed to have a wide range of appearances, textures, mouthfeels, and flavors. For instance, they could be red, orange, green, yellow, blue, or beige; they could be spheres, ovals, cubes, or pyramids; they could be hard/soft or brittle/pliable; and they could be lemon, thyme, curry, or chili flavored. Consequently, there is great flexibility in creating NAPS that could be eaten in situations where animal products are normally consumed, for example, with pasta, rice, potatoes, bread, soups, or salads. This article reviews the science behind the formulation of NAPS, highlights factors impacting their appearance, texture, flavor, and nutritional profile, and discusses methods that can be used to formulate, produce, and characterize them. Finally, it stresses the need for further studies on this new category of foods, especially on their sensory and consumer aspects.

Comparison of Physical and Compositional Attributes between Commercial Plant-Based and Dairy Yogurts

A primary strategy led by the food industry to improve the sustainability of the agricultural food supply is the development of modern plant-based alternatives. The information provided via marketing and product packaging provides consumers with the expectation that these products provide a similar product experience to conventional products, yet it is not well understood whether these commercial alternative products are comparable to traditional animal-based products. To aid in developing improved plant-based products, this study aimed to compare the quality and physical attributes of commercially available plant-based and dairy yogurts. Using instrumental methods, commercially available yogurt products were analyzed for their pH, titratable acidity, color, water activity, moisture content, and rheology, which included 13 plant-based (almond, cashew, coconut, oat, soy) and 8 whole-milk dairy yogurts. The present study reveals that the plant-based and dairy yogurts had no significant differences in pH, lactic acid, water activity, or moisture content. However, there were significant differences in the color and texture properties between the plant-based and dairy yogurts. Additionally, significant differences were observed across the plant-based yogurt products in terms of their color and texture properties. This highlights the need for additional studies to determine how individual ingredients influence the physical characteristics and textural properties to direct the development of plant-based yogurts. Improving upon the physicochemical properties of plant-based yogurt may encourage more consumers to adopt a more sustainable diet.

Use of hydration properties of proteins to understand their functionality and tailor texture of extruded plant-based meat analogues

Different protein sources create distinct textures in plant-based meat due to differences in their hydration properties when exposed to different time, temperature, and shear regimes, which in turn depend upon their solubility, protein structure, and specific amino acids. This research aimed to identify these differences and manipulate them to reach a desired texture utilizing simple and reproducible analytical methods to characterize protein properties as either cold or heat swelling. Protein functionality was determined through least gelation concentration (LGC), water absorption index (WAI), and rapid visco analysis (RVA). Cold swelling or CS proteins (pea protein isolate, soy protein isolate, Arcon S soy protein concentrate) were characterized by an LGC < 14% and/ or WAI > 4.0 g/g, while LGC > 16% and/ or WAI < 4.0 g/g indicates proteins with heat swelling or HS properties (Arcon F soy protein concentrate, wheat gluten, and fava protein concentrate). An RVA peak time of around or less than 3 min (<75°C peak temperature) indicated CS properties while greater than 3.5 min (>80°C peak temperature) was considered HS. Protein mixes or treatments comprising mainly of different combinations and ratios of CS proteins were hypothesized to create a softer textured vegetable protein product or texturized vegetable protein (TVP) and those based on HS proteins a firmer TVP. Bulk density was higher for HS treatments (274-287 g/L) than for CS treatments (160-223 g/L). CS treatments exhibited a microstructure that was porous, while HS showed a dense, laminar microstructure. Texture profile analysis showed that CS treatments seemed to show a lower hardness (1154-1595 g) than the HS treatments (1893-2231 g). PRACTICAL APPLICATION: Controlling texture can be a valuable tool when producing a plant-based meat product. Different applications have various texture requirements. For example, a plant-based fish stick would require a softer texture than a hamburger or chicken nugget. By increasing the knowledge of how protein functionality affects meat analogue texture, the time needed to produce new products with novel textures can be reduced. Money could also be saved by being able to quickly replace ingredients with a more affordable or accessible protein with similar swelling abilities to preserve product quality.

Carrageenan impact on digestive proteolysis of meat proteins in meatballs or soluble hydrolyzed collagen

In a health-conscious age, vivid discussion has been made on the healthfulness of processed foods and food additives. This study focuses on carrageenan (CGN), an approved but debated family of sulphated galactans from algae used as gelling, thickening and stabilizing agents but with indications of possible adverse effects, including as an inhibitor of digestive proteolysis. To challenge this inhibitory hypothesis, food-grade kappa-, iota and lambda-CGN preparations were used to produce beef meatballs whose proteolysis was studied using an in vitro digestion model coupled to various proteomic analyses. Results show that CGN anti-nutritional effects are abolished in beef meatballs. Specifically, proteomic analysis of gastric digesta of myosin light chain 1 (MYL1), alpha skeletal muscle (ACTA1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and fructose-bisphosphate aldolase (ALDOA) reveal no appreciable differences in the profiles of bioaccessible peptides. Separate digestions of a soluble collagen hydrolysate show CGN does inhibit proteolysis of soluble collagen, therefore supporting the notion that the meat matrix confers a shielding effect that eliminates CGN ability to interfere with digestive proteolysis. Thus, this work shows that CGN ability to hinder digestive proteolysis may not apply to all foods and contributes evidence important to the discussions on CGN uses, indications and regulatory status.

Microbial gas fermentation technology for sustainable food protein production

The development of novel, sustainable, and robust food production technologies represents one of the major pillars to address the most significant challenges humanity is going to face on earth in the upcoming decades - climate change, population growth, and resource depletion. The implementation of microfoods, i.e., foods formulated with ingredients from microbial cultivation, into the food supply chain has a huge potential to contribute towards energy-efficient and nutritious food manufacturing and represents a means to sustainably feed a growing world population. This review recapitulates and assesses the current state in the establishment and usage of gas fermenting bacteria as an innovative feedstock for protein production. In particular, we focus on the most promising representatives of this taxon: the hydrogen-oxidizing bacteria (hydrogenotrophs) and the methane-oxidizing bacteria (methanotrophs). These unicellular microorganisms can aerobically metabolize gaseous hydrogen and methane, respectively, to provide the required energy for building up cell material. A protein yield over 70% in the dry matter cell mass can be reached with no need for arable land and organic substrates making it a promising alternative to plant- and animal-based protein sources. We illuminate the holistic approach to incorporate protein extracts obtained from the cultivation of gas fermenting bacteria into microfoods. Herein, the fundamental properties of the bacteria, cultivation methods, downstream processing, and potential food applications are discussed. Moreover, this review covers existing and future challenges as well as sustainability aspects associated with the production of microbial protein through gas fermentation.

3D printable vegan plant-based meat analogue: Fortification with three different mushrooms, investigation of printability, and characterization

In this study, a meat analogue formulation prepared using different protein sources as a printable ink for 3D printers and fortified with three different mushroom cultivars (reishi, Ganoderma lucidum (GL); saffron milk-cap, Lactarius deliciosus (LD); and oyster, Pleurotus ostreatus (PO)). 3D printing performance of the prepared inks was evaluated by factorial design in terms of nozzle height, printing speed, and flow compensation. New methods of maximum layer height and reprintability of plant-based meat analogues were conducted for the first time. Inks were characterized by analyzing rheological properties, microstructure, color characteristics, texture profile, cooking loss, amino acid content, and sensory evaluation. Results showed that the nozzle height and printing speed were found to be most effective on accuracy of prints and smoothness of layers. All inks (C, GL, LD and PO) represented shear-thinning and gel-like viscoelastic behavior (G' > G″) with predominant elasticity (tan δ < 1). Therefore they were suited for 3D printing and possessed supporting the following layers for additive manufacturing as well as meeting the criteria for a stable structure. Meat analogue was printed successfully without perceived defects in all formulations, except the GL was looking linty. LD and PO inks brought the advantage of recycling as a result of their re-printability whereas GL could not. Moreover, mushroom fortification reduced hardness, stiffness, springiness, and chewiness properties of the meat analogues whereas it increased the juiciness with reasonable overall acceptance. Mushroom fortification also enhanced the nutritional value and improved release of umami amino acids. The findings of the study demonstrated that mushrooms could be a functional and nutritious candidate for 3D printable plant-based meat analogues.

Quantitative characterizations of visual fibrousness in meat analogues using automated image analysis

A desirable quality of plant-based meat analogues is to resemble the fibrous structure of cooked muscle meat. While texture analysis can characterize fibrous structures mechanically, assessment of visual fibrous structures remains subjective. Quantitative assessment of visual fibrous structures of meat analogues relies on expert knowledge, is resource-intensive, and time-consuming. In this study, a novel image-based method (Fiberlyzer) is developed to provide automated, quantitative, and standardized assessment of visual fibrousness of meat analogues. The Fiberlyzer method segments fibrous regions from 2D images and extracts fiber shape features to characterize the fibrous structure of meat analogues made from mung bean, soy, and pea protein. The computed fiber scores (the ratio between fiber length and width) demonstrate a strong correlation with expert panel evaluations, particularly on a per-formulation basis (r2  = 0.93). Additionally, the Fiberlyzer method generates fiber shape features including fiber score, fiber area, and the number of fiber branches, facilitating comparisons of structural similarity between meat analogue samples and cooked chicken meat as a benchmark. With a simple measurement setup and user-friendly interface, the Fiberlyzer method can become a standard tool integrated into formulation development, quality control, and production routines of plant-based meat analogue. This method offers rapid, cheap, and standardized quantification of visual fibrousness, minimizing the need for expert knowledge in the process of quality control.

Understanding Protein Functionality and Its Impact on Quality of Plant-Based Meat Analogues

A greater understanding of protein functionality and its impact on processing and end-product quality is critical for the success of the fast-growing market for plant-based meat products. In this research, simple criteria were developed for categorizing plant proteins derived from soy, yellow pea, and wheat as cold swelling (CS) or heat swelling (HS) through various raw-material tests, including the water absorption index (WAI), least gelation concentration (LGC), rapid visco analysis (RVA), and % protein solubility. These proteins were blended together in different cold-swelling: heat-swelling ratios (0:100 to 90:10 or 0-90% CS) and extruded to obtain texturized vegetable proteins (TVPs). In general, the WAI (2.51-5.61 g/g) and protein solubility (20-46%) showed an increasing trend, while the LGC decreased from 17-18% to 14-15% with an increase in the % CS in raw protein blends. Blends with high CS (60-90%) showed a clear RVA cold viscosity peak, while low-CS (0-40%) blends exhibited minimal swelling. The extrusion-specific mechanical energy for low-CS blends (average 930 kJ/kg) and high-CS blends (average 949 kJ/kg) was similar, even though both were processed with similar in-barrel moisture, but the former had substantially lower protein content (69.7 versus 76.6%). Extrusion led to the aggregation of proteins in all treatments, as seen from the SDS-PAGE and SEC-HPLC analyses, but the protein solubility decreased the most for the high-CS (60-90%) blends as compared to the low-CS (0-40%) blends. This indicated a higher degree of crosslinking due to extrusion for high CS, which, in turn, resulted in a lower extruded TVP bulk density and higher water-holding capacity (average 187 g/L and 4.2 g/g, respectively) as compared to the low-CS treatments (average 226 g/L and 2.9 g/g, respectively). These trends matched with the densely layered microstructure of TVP with low CS and an increase in pores and a spongier structure for high CS, as observed using optical microscopy. The microstructure, bulk density, and WHC observations corresponded well with texture-profile-analysis (TPA) hardness of TVP patties, which decreased from 6949 to 3649 g with an increase in CS from 0 to 90%. The consumer test overall-liking scores (9-point hedonic scale) for TVP patties were significantly lower (3.8-5.1) as compared to beef hamburgers (7.6) (p < 0.05). The data indicated that an improvement in both the texture and flavor of the former might result in a better sensory profile and greater acceptance.

Enhancing textural properties in plant-based meat alternatives: The impact of hydrocolloids and salts on soy protein-based products

Consumer studies suggest that the meat-like texture of plant-based meat alternatives is crucial for the market success of these products. Many meat analogues contain wheat gluten, because it is cost-effective and give rise to nice fibrous structures. However, individuals with celiac disease cannot consume products containing wheat gluten producing a fibrous structure. To provide meat-like textures, different hydrocolloids with appropriate salt concentrations could be used. Therefore, this study investigated the influence of different hydrocolloids, including high acyl gellan gum, low acyl gellan gum, high methoxyl pectin, low methoxyl pectin, and xanthan at 2%, as well as two types of salts (CaCl2 and NaCl) at three concentrations (0%, 0.5%, and 1%) on the macrostructure, microstructure, and mechanical properties of plant-based meat alternatives containing only soy protein isolate and without wheat gluten. The addition of hydrocolloids and salts increased the cross-link bonds and structural compactness at the microscopic level and enhanced the fibrous structure at the microscopic level at different extent. These findings provide insight into how the addition of salts and hydrocolloids can effect plant-based meat alternatives without wheat gluten, which have practical implications for the food industry and are important for their success in the market.

Rheological properties of dry-fractionated mung bean protein and structural, textural, and rheological evaluation of meat analogues produced by high-moisture extrusion cooking

A closed cavity rheometer was used to study the rheology of dry-fractionated mung bean protein -DFMB- (55% protein d.m.). Then, the high-moisture extrusion cooking at 40% and 50% moisture contents and different temperatures (115, 125, 135 and 145 °C) was performed, investigating the impact on structural, textural, and rheological properties of extrudates. When subjected to a temperature ramp (40-170 °C), DFMB showed an increase of G* from 70 °C, as a consequence of starch gelatinization and protein gelation. The peak, indicating the end of aggregation reactions, was at 105 °C and 110 °C for DFMB at 50% and 40% moisture content, respectively. The time sweep analysis described the protein behavior in no-shear/shear conditions, highlighting a more pronounced effect of the temperatures compared to moisture content. During the extrusion cooking, the temperature increase led to a decrease of pressure, indicating a reduction of the melt viscosity. The microstructure of the extrudates showed a more pronounced anisotropic profile when higher temperatures were applied. Hardness, chewiness, and cohesion were directly correlated with the temperature, which also affected the rheological properties of extrudates. A combination of textural and rheological analyses can offer a clear overview of the structural characteristics of meat analogues.

How Different Dimensions Shape the Definition of Meat Alternative Products: A Scoping Review of Evidence between 2000 and 2021

Consumer awareness of meat-associated health and environmental risks is increasing and motivates a shift toward consuming meat alternatives. This is also reflected in efforts invested in studying meat alternatives from the perspective of nutritional, environmental, and consumer sciences. Despite shared research interest, these studies cannot be readily compared and interpreted because there is no clear consensus on what meat alternatives are. Scholarly debates on acceptance, nutritional value, and environmental advantages of meat alternatives would benefit from a clear definition of meat alternatives. With the goal of defining meat alternatives, relevant scientific literature in the past 10 years was systematically searched and screened guided by the scoping review Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension. The initial search resulted in >100,000 hits, which was reduced to 2465 papers. Next, titles and abstracts were scrutinized using Rayyan.ai, resulting in 193 articles considered for the present review. Article screening and data extraction was performed using ATLAS.ti software. Three major themes were identified to define meat alternative products including: 1) producing and sourcing of ingredients; 2) product characteristics (that is, sensory characteristics, nutritional value, and health profile, social and environmental sustainability profile); and 3) consumer characteristics concerning the marketing and consumption context. Meat alternatives are multifaceted, that is, certain products can be considered as meat alternatives in some context, but not in another context. For any product, it is impossible to unequivocally state that it is a meat alternative. There is a lack of consensus from the diverse literature on what constitutes meat alternatives. However, products may be qualified as meat alternatives according to three key criteria as proposed in a taxonomy: 1) production and sourcing, 2) product characteristics, and/or 3) consumption. We recommend researchers (and other stakeholders) to do so as it allows for better informed future discussions of meat alternatives.

Properties of Texturized Vegetable Proteins from Edible Mushrooms by Using Single-Screw Extruder

This research aimed to determine the feasibility of using mushrooms as an alternative ingredient in texturized vegetable protein (TVP) production using a single-screw extruder. TVPs from King Oyster (TVP-KO) and Pheonix mushroom (TVP-PH) were successfully developed and characterized. The visual appearance of TVP was reddish-brown, with a distinct roasted mushroom-soybean aroma. When rehydrated and cooked, both TVPs provided a minced meat-like appearance and chewy meat texture comparable to commercial TVP (TVP-Com); however, they had inferior water and oil holding and rehydration capacities. TVPs contained comparable protein content to TVP-Com (45–47 wt%), slightly lower carbohydrate content (33–36 wt% vs. 39 wt%), and ash (3–4 wt% vs. 8 wt%), but higher lipid content (7–8 wt% vs. 0.84 wt%) than TVP-Com. Sai-aua prepared from TVP-KO gained the highest overall acceptability. Mushrooms proved to be a potential source for TVP production due to their availability, low cost, nutritional value, and health benefits. Moreover, this finding helps add value to traditional meat products, which offer an opportunity for developing non-animal products with satisfactory sensory properties and low cost. In addition, the study would provide scientific resources for developing plant-based meat products that address health awareness and economic and environmental sustainability concerns.

Fibrous food and particle size influence electromyography and the kinematics of oral processing

Structure-sensory relationships are essential for understanding food perception. Food microstructure impacts how a food is comminuted and processed by the human masticatory system. This study investigated the impact of anisotropic structures, explicitly the structure of meat fibers, on the dynamic process of mastication. For a general understanding of texture-structure relationships, the three typically used deformation-tests: Kramer shear cell-, Guillotine cutting- and texture-profile-analyses were conducted. 3D jaw movements and muscle activities of the masseter muscle were additionally tracked and visualized using a mathematical model. Particle size had a significant effect on jaw movements and muscle activities for both the homogeneous (isotropic) and fibrous (anisotropic) meat-based samples with the same composition. Mastication was described using jaw movement and muscle activity parameters determined for each individual chew. The adjusted effect of fiber length was extracted from the data, suggesting that longer fibers induce a more strenuous chewing in which the jaw undergoes faster and wider movements requiring more muscle activity. To the authors' knowledge, this paper presents a novel data analysis approach for identifying oral processing behavior differences. This is an advancement on previous studies because a holistic overview of the entire mastication process can be visualized.

Meat substitutes: Resource demands and environmental footprints

The modern food system is characterized with high environmental impact, which is in many cases associated with increased rates of animal production and overconsumption. The adoption of alternatives to meat proteins (insects, plants, mycoprotein, microalgae, cultured meat, etc.) might potentially influence the environmental impact and human health in a positive or negative way but could also trigger indirect impacts with higher consumption rates. Current review provides a condensed analysis on potential environmental impacts, resource consumption rates and unintended trade-offs associated with integration of alternative proteins in complex global food system in the form of meat substitutes. We focus on emissions of greenhouse gases, land use, non-renewable energy use and water footprint highlighted for both ingredients used for meat substitutes and ready products. The benefits and limitations of meat substitution are highlighted in relation to a weight and protein content. The analysis of the recent research literature allowed us to define issues, that require the attention of future studies.

Exploring user-generated content related to vegetarian customers in restaurants: An analysis of online reviews

This study aimed to explore and evaluate factors that impact the dining experience of vegetarian consumers within a range of vegetarian-friendly restaurants. To explore the factors and understand consumer experience, this study analyzed a vast number of user-generated contents of vegetarian consumers, which have become vital sources of consumer experience information. This study utilized machine-learning techniques and traditional methods to examine 54,299 TripAdvisor reviews of approximately 1,008 vegetarian-friendly restaurants in London. The study identified 21 topics that represent a holistic opinion influencing the dining experience of vegetarian customers. The results suggested that "value" is the most popular topic and had the highest topic percentage. The results of regression analyses revealed that five topics had a significant impact on restaurant ratings, while 12 topics had negative impacts. Restaurant managers who pay close attention to vegetarian aspects may utilize the findings of this study to satisfy vegetarian consumer requirements better and enhance service operations.

Use of legume flours and fiber for tailoring structure and texture of pea protein-based extruded meat alternatives

The overall objective of this study was to understand texturization of pea protein isolate (PPI) using low moisture extrusion, and investigate protein interactions, functionality, and cross-linking with the inclusion of different levels of pea fiber (5-15%) and different types of starch-containing legume flours (20% chickpea flour or pea flour). PPI/ legume flour raw formulations had 18-27% lower water absorption capacity (WAC) as compared to the PPI control. However, WAC increased by 8-16% with the addition of pea fiber to a PPI/ legume flour control. Rapid Visco Analysis trends mirrored these results with peak viscosity shifting to higher temperatures with the addition of legume flour and lower temperatures with the addition of pea fiber. The role of starch in interfering with protein hydrophilic interactions and that of fiber in decoupling this effect were discussed. These interactions determined extruded textured protein properties, with more layering and denser products (174-229% higher bulk density as compared to control) observed with the addition of legume flours leading to lower water hydration capacity (WHC), as opposed to more cellular and porous microstructure (55-58% lower bulk density as compared to control) with the addition of fiber. Bulk density and WHC trends due to these porosity and layering effects impacted the instrumental texture characteristics of ground hydrated product, including hardness that increased from 475 g to 837-2334 g with the higher layering caused by starch, but decreased from 1295 g to 534-1050 g due to the porosity induced by fiber. To summarize, the use of legume flours and fiber can allow flexibility in targeting specific qualities while reducing costs and increasing sustainability of plant-based meats. PRACTICAL APPLICATION: Health, environment, and animal welfare concerns are creating a growing movement toward plant-based meat. Pea protein isolate and concentrate have become popular ingredients for texturized plant protein. Understanding of the role of starch and fiber in the structuring of textured pea protein could lead to use of legume flours and co-products of protein isolation to reduce cost and increase sustainability and nutrition of meat alternatives while targeting desired textural attributes.

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.

Insights into characterizing and producing anisotropic food structures

Besides the flavor profile of food, texture plays a major role in terms of the acceptance and likeability of food products. In contrast to gel-like homogenous isotropic structures, where the characterization is established and structure-texture mechanisms are well understood, there is still a lack of knowledge in the field of anisotropic complex food matrices. Food systems that show anisotropic properties in terms of macroscopic mechanical anisotropy as in grown meat, or mixed complex systems where anisotropic shaped particles or fibers are embedded into an isotropic matrix are challenging to characterize, hence the structure-texture correlation is not trivial to understand. In this paper, we bring together the state of the art of different anisotropic structures as a source of food, their formation in terms of structured plant proteins, and consequently the structure-texture correlation of those. Characteristic terms and properties to differentiate between anisotropic systems are introduced with the purpose to facilitate characterization of those. Based on the here provided terms and characteristics, further studies toward understanding such systems and their perception can be conducted. Beyond that, a first opinion on crucial influencing factors on the perception of anisotropic systems and their mechanistic background is provided.

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.

Recent trends in design of healthier plant-based alternatives: nutritional profile, gastrointestinal digestion, and consumer perception

In recent years, various types of plant-based meat, dairy, and seafood alternatives merged in the health-conscious consumer market. However, plant-based alternatives present complexity in terms of nutritional profile and absorption of nutrients after food ingestion. Thus, this review summarizes current strategies of plant-based alternatives and their nutritional analysis along with gastrointestinal digestion and bioavailability. Additionally, regulatory frameworks, labeling claims, and consumer perception of plant-based alternatives are discussed thoroughly with a focus on status and future prospects. Plant-based alternatives become a mainstream of many food-processing industries with increasing alternative plant-based food manufacturing industries around the world. Novel food processing technologies could enable the improving of the taste of plant-based foods. However, it is still a technical challenge in production of plant-based alternatives with authentic meaty flavor. In vitro gastrointestinal digestion studies revealed differences in the digestion and absorption of plant-based alternatives and animal-based foods due to their protein type, structure, composition, anti-nutritional factors, fibers, and polysaccharides. Overall, plant-based alternatives may facilitate the replacement of animal-based foods; however, improvements in nutritional profile and in vitro digestion should be addressed by application of novel processing technologies and food fortification. The specific legislation standards should be necessary to avoid consumer misleading of plant-based alternatives.

Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.

Proposed Methods for Testing and Comparing the Emulsifying Properties of Proteins from Animal, Plant, and Alternative Sources

The food industry is trying to reformulate many of its products to replace functional ingredients that are chemically synthesized or isolated from animal sources (such as meat, fish, eggs, or milk) with ingredients derived from plant or microbial sources. This effort is largely a result of the demand for foods that are better for the environment, human health, and animal welfare. Many new kinds of plant- or microbial-derived proteins are being isolated for potential utilization as functional ingredients by the food industry. A major challenge in this area is the lack of standardized methods to measure and compare the functional performance of proteins under conditions they might be used in food applications. This information is required to select the most appropriate protein for each application. In this article, we discuss the physicochemical principles of emulsifier functionality and then present a series of analytical tests that can be used to quantify the ability of proteins to form and stabilize emulsions. These tests include methods for characterizing the effectiveness of the proteins to promote the formation and stability of the small droplets generated during homogenization, as well as their ability to stabilize the droplets against aggregation under different conditions (e.g., pH, ionic composition, temperature, and shearing). This information should be useful to the food industry when it is trying to identify alternative proteins to replace existing emulsifiers in specific food applications.

Materials Properties, Oral Processing, and Sensory Analysis of Eating Meat and Meat Analogs

To increase the appeal of plant protein-based meat analogs, further progress needs to be made in their sensory perception. Given the limited number of studies on meat analogs, this review focuses on structure, oral processing, and sensory perception of meat and subsequently translates the insights to meat analogs. An extensive number of publications has built the current understanding of meat mechanical and structural properties, but inconsistencies concerning terminology and methodology execution as well as the wide variety in terms of natural origin limit solid conclusions about the control parameters for oral processing and sensory perception. Consumer-relevant textural aspects such as tenderness and juiciness are not directly correlated to single structural features but depend on an interplay of multiple factors and thus require a holistic approach. We discuss the differences in mastication and disintegration of meat and meat analogs and provide an outlook toward converting skeptical consumers into returning customers. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Improved functional properties of meat analogs by laccase catalyzed protein and pectin crosslinks

The gap between the current supply and future demand of meat has increased the need to produce plant-based meat analogs. Methylcellulose (MC) is used in most commercial products. Consumers and manufacturers require the development of other novel binding systems, as MC is not chemical-free. We aimed to develop a novel chemical-free binding system for meat analogs. First, we found that laccase (LC) synergistically crosslinks proteins and sugar beet pectin (SBP). To investigate the ability of these SBP-protein crosslinks, textured vegetable protein (TVP) was used. The presence of LC and SBP improved the moldability and binding ability of patties, regardless of the type, shape, and size of TVPs. The hardness of LC-treated patties with SBP reached 32.2 N, which was 1.7- and 7.9-fold higher than that of patties with MC and transglutaminase-treated patties. Additionally, the cooking loss and water/oil-holding capacity of LC-treated patties with SBP improved by up to 8.9-9.4% and 5.8-11.3%, compared with patties with MC. Moreover, after gastrointestinal digestion, free amino nitrogen released from LC-treated patties with SBP was 2.3-fold higher than that released from patties with MC. This is the first study to report protein-SBP crosslinks by LC as chemical-free novel binding systems for meat analogs.

Fermented meat sausages and the challenge of their plant-based alternatives: A comparative review on aroma-related aspects

Traditional fermented meat sausages are produced around the world due to their convenience and sensory characteristics which are responsible for their high acceptability. They constitute a cultural heritage as shown by the high diversity of products around the world. Recent trends are addressing issues regarding innovation in their formulation by reduction of salt, fat and additives (curing salts). However, the current trend towards a reduction in the consumption of meat has produced an increase in the formulation of meat product analogues. This trend is the main focus of producers to offer new attractive products to consumers even though the aroma profile of traditional fermented meat sausages is not reached. In this manuscript, we review and discuss the chemistry of aroma formation in traditional fermented meat sausages in contrast to the potential of plant-based ingredients used in meat analogues.

Digestibility and gastrointestinal fate of meat versus plant-based meat analogs: An in vitro comparison

Plant-based meat analogs are likely to have different gastrointestinal fates than real meat products due to differences in their compositions and structures. Here, we compared the gastrointestinal fate of ground beef and ground beef analogs using the INFOGEST in vitro digestion model, focusing on differences in microstructure, physicochemical properties, lipid digestion, and protein digestion in different regions of the model gut. The presence of dietary fibers in the beef analogs increased their apparent shear viscosity in the gastrointestinal fluids, which may have inhibited lipid digestion in the small intestine. The proteins in the beef analogs were digested more rapidly in the stomach but less rapidly in the small intestine, which may have been due to differences in protein type (globular soy versus fibrous beef proteins), structural organization, and the presence of dietary fibers in the meat analogs.

A Consumer Segmentation Study for Meat and Meat Alternatives in Switzerland

The aim of this study was to identify consumer groups regarding meat and meat alternatives, which are homogeneous in themselves but very different from one another. To date, the literature has analysed the attitudes towards, and the motives behind, the consumption of meat and meat alternatives. However, segmentation research portraying homogeneous consumer groups that are consuming or willing to consume meat alternatives is lacking. This study closes this research gap and, in doing so, also shows how meat consumption is related to the consumption of alternative products. A questionnaire was sent out to a random sample in the German- and French-speaking parts of Switzerland, resulting in 561 responses. A hierarchical cluster analysis using seven scales revealed six distinct consumer groups, which covered all types of consumers, from the uncompromising meat-eater to the health-conscious meat avoider. The results show that meat alternatives are not always consumed as a substitute for meat but can also be a complementary component in one’s diet. This study contributes to the scientific literature by providing useful information for the food industry involved in producing and marketing meat and meat alternatives to different target groups.