Production Of Meat Analogues Research Articles

Plant‐based meat analogues marketed in Catalonia: analysis of contaminants, essential elements, microbiological and physicochemical status, dietary intake estimation and health risk assessment

Abstract The latest barometer of food safety in Catalonia conducted by the Catalan Food Safety Agency (ACSA for its initials in Catalan) in 2021 shows that 28.7% of the population consumes meat analogues (substitutes). The main reasons for consuming this type of food are animal welfare, followed by environmental and health reasons. Due to the increasing demand for plant‐based meat analogues, the number of such products available on the market has also increased. Currently, however, there is a lack of knowledge regarding the composition of meat analogue products and their impact on human health. In this context, it was deemed necessary to complement the first report by the ACSA Scientific Advisory Committee on Food Safety with the present and more specific study on the content of contaminants and essential elements, several microbiological parameters and physicochemical characteristics of plant‐based meat analogues in order to assess the population of Catalonia's exposure to their potential health risks. The results indicate that the content of essential elements (Ca, Cr, Fe and Zn) and contaminants (As, Cd, Hg, Pb and Ni) in the plant‐based meat analogues are mostly of the same order of magnitude as those observed in the meat products evaluated in the total diet studies. The estimated dietary intakes for the evaluated population groups show values well below the toxicological safety values established for the different contaminants. Only for nickel could the risk assessment with regard to systemic contact dermatitis indicate a potential health problem for nickel‐sensitised individuals. The estimated dietary intake of essential elements associated with the consumption of one serving (100 g) of meat analogues hamburgers, or sausages, or meatballs or vegetable strips represents between 6.9 and 67.7% of the established recommended daily intake values. Out of the total number of samples evaluated, “Salmonella spp.” was detected in 6 samples. “Listeria monocytogenes” was detected by PCR in 3 samples; quantification was always lower than 10 cfu/g. The physicochemical characteristics showed very similar values in all meat analogues samples. The observed water activity and pH values favour the growth of microorganisms. To ensure the safety of products it is paramount that the need to subject the food to a complete heat treatment prior to consumption is highlighted on the labelling.

Safety of soy leghemoglobin from genetically modified Komagataella phaffii as a food additive.

The EFSA Panel on Food Additive and Flavourings (FAF Panel) provides a scientific opinion on the safety of soy leghemoglobin from genetically modified Komagataella phaffii as a food additive in accordance with Regulation (EC) No 1331/2008. The proposed food additive, LegH Prep, is intended to be used as a colour in meat analogue products. The yeast Komagataella phaffii strain MXY0541 has been genetically modified to produce soy leghemoglobin; the safety of the genetic modification is under assessment by the EFSA GMO Panel (EFSA-GMO-NL-2019-162). The amount of haem iron provided by soy leghemoglobin from its proposed uses in meat analogue products is comparable to that provided by similar amounts of different types of meat. The exposure to iron from the proposed food additive, both at the mean and 95th percentile exposure, will be below the 'safe levels of intake' established by the NDA Panel for all population groups. Considering that the components of the proposed food additive will be digested to small peptide, amino acids and haem B; the recipient (non GM) strain qualifies for qualified presumption of safety status; no genotoxicity concern has been identified and no adverse effects have been identified at the highest dose tested in the available toxicological studies, the Panel concluded that there was no need to set a numerical acceptable daily intake (ADI) and that the food additive does not raise a safety concern at the proposed use in food category 12.9 and maximum use level. The Panel concluded that the use of soy leghemoglobin from genetically modified Komagataella phaffii MXY0541 as a new food additive does not raise a safety concern at the proposed use and use level. This safety evaluation of the proposed food additive remains provisional subject to the ongoing safety assessment of the genetic modification of the production strain by the GMO Panel (EFSA-GMO-NL-2019-162).

Cysteine, sodium metabisulfite, and glutathione enhance crosslinking between proteins during high moisture meat analog extrusion processing and may improve the fibrousness of the products.

High moisture meat analog (HMMA) products processed using extrusion have become increasingly popular in the last few years. Because the formation of disulfide bonds is believed to play a critical role in the texturization mechanism, this study aimed to understand how chemical compounds capable of reducing disulfide bonds, specifically cysteine, sodium metabisulfite, and glutathione, affect the texture and the chemical interactions between the proteins. Wheat protein blended with cysteine, sodium metabisulfite, or glutathione at levels of 0, 0.5, 1.0, 2.5, 5.0, and 7.5 g kg-1 was extruded at three different temperatures (115, 140, and 165 °C) using a co-rotating twin-screw extruder. The feed rate (85 g min-1), the moisture content (600 g kg-1), and the screw speed (300 rpm) were kept constant. Unextruded and extruded material was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, polymeric protein fractionation, and sulfhydryl group/disulfide bond analysis. Extruded samples were further analyzed for their hardness and their anisotropic index. The inclusion of reductants significantly affected the structure of the obtained extrudates. Although reducing agents had a relatively small impact on the total amount of disulfide bonds, their action significantly enhanced crosslinking between the proteins. At select conditions, samples with high fibrousness were specifically obtained when cysteine or sodium metabisulfite was included at levels of 5.0 g kg-1. In the presence of reducing agents, it is believed that disulfide bonds are split earlier during the process without binding to them, giving the protein strands more time to unravel and align, leading to a better flow behavior and more fibrous products. © 2024 Society of Chemical Industry.

Relating the protein denaturation degree and solubility of soy protein isolates to the structure of high moisture extrudates

Commercial soy protein isolates (SPI) with high protein denaturation degrees and low solubilities are often used raw materials for the production of meat analogues with high moisture extrusion (HME). The impact of such SPI properties on structure formation and protein-protein interactions/reactions that occur during HME processing is not well-understood. Therefore, SPI with (i) native and soluble proteins, (ii) denatured and aggregated proteins or (iii) blends thereof were subjected to lab-scale HME processing. Most native and soluble SPI proteins took part in the formation of new non-covalent interactions and disulfide bonds during HME processing, which resulted in a layered extrudate microstructure. In addition, even after disruption of non-covalent and covalent bonds, high MW aggregates (>100 kDa) were present in the extrudate. SPI with highly aggregated protein had low protein extractability and HME did not cause a pronounced further reduction in this regard. HME did, however, result in the formation of a fibrous extrudate structure. Extrusion of blends with intermediate content of both SPIs resulted in the highest extrudate hardness and cutting strength. These findings demonstrate a significant impact of SPI protein denaturation degree and solubility on high moisture extrudate structure and texture. Hence, in-depth evaluation of the protein physical properties of raw materials used for HME processing will aid in controlling product properties.

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

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

Encapsulation of roast beef flavor by soy protein isolate/chitosan complex Pickering emulsions to improve its releasing properties during the processing of plant-based meat analogues

During the production of plant-based meat analogues (PBMA), a significant loss of flavor characteristic compounds in meat-flavor essences could be observed. Pickering emulsion-based encapsulation is an effective method to improve their stability. Therefore, a soy protein isolate (SPI)/chitosan (CS) complex Pickering emulsion was fabricated to encapsulate roast beef flavor (RBF) and further applied in the processing of PBMA. Our results indicated that the network structure of emulsions was dominated by elasticity, while hydrogen and covalent bonding interactions played important roles in the encapsulation process. The release rate of flavor compounds gradually increased with the increase of pH value, glutamine transaminase, NaCl content, heating temperature or heating time, while encapsulation significantly reduced the loss of characteristic aroma compounds. In addition, the releasing characteristics of aroma compounds and textural properties of PBMA were greatly improved by treating with RBF-loaded emulsions. Consequently, the emulsions were promising to improve the flavor quality of PBMA.

Exploring the mechanism of amylose/amylopectin improving formation of yeast-soy protein high-moisture extrudates based on small and large amplitude oscillatory shear rheology

Yeast protein (YP) has high production efficiency and comprehensive nutritional value compared to soy protein isolate (SPI). However, relatively higher proportion of YP replaces SPI seriously affect the structure of extrudates in the production of meat analogues. This study investigated starch addition (amylose/amylopectin) on the structure of YP-SPI extrudates with higher YP proportion and formation mechanism by using closed cavity rheometer simulated the high-moisture extrusion process (mixing, melting, cooling, and extrudates). The proportions of YP:SPI:amylose:amylopectin were set as 5:5:0:0, 5:4:1:0, 5:4:0:1, and 5:4:0.5:0.5. Starch addition could improve the structure formation of extrudes, but the improvement effect varied depending on the type of starch. Compared to amylose, incorporating amylopectin significantly enhanced the fibrous degree of extrudates and improved their tensile resistance. Furthermore, small amplitude oscillatory shear (SAOS) was used to establish texture map. In the mixing and melting zones, amylose decreased the miscibility of protein and starch phase, while amylopectin had positive effect on the integrity and uniformity of protein network. Amylopectin could transform the extrudates into a “mushy” state, contributing to reconstruct protein network. Large amplitude oscillatory shear (LAOS) demonstrated amylopectin had higher energy dissipation ratio in the cooling zone, indicating the uniform “phase separation” facilitated the formation of fiber structure of extrudates. This study provides technical reference for the preparation of high-moisture extrudates using YP as a substitute for SPI based on starch type addition.

Soluble and insoluble fractions of soy protein isolate affect the properties of its high-moisture extrudates

This research focused the impact of the variation in insoluble soy protein isolate (ISPI) and soluble soy protein isolate (SSPI) contents on the rheological properties of highly-concentrated SPI during extrusion-like conditions and the physiochemical, mechanical, and morphological characteristics of its extrudates. Results showed that increased ISPI content could resist great shear forces and increase the viscoelasticity of SPI samples. In addition, the increase of ISPI content in SPI samples also contributed to enhance the tensile strength and mechanical anisotropy, further created a distinct fibrous structures of extrudates. While higher SSPI content can form heat-induced reverseble aggregates via hydrophobic interaction and disulfide bonds, reduce the water mobility and facilitate the formation of a more uniform protein-water phase. The differences in solubility revealed the dominance of non-covalent bonds in ISS-40 extrudate (100% ISPI) and highlighted the important role of disulfide bonds in ISS-04 extrudate (100% SSPI). Possible mechanisms are proposed to explain the contrasting behavior of ISPI and SSPI under thermomechanical treatment. These insights explore the formation of protein multiphase system structures and offer valuable guidance for developing meat analogue products.

Nutritional and functional properties of photosynthetic microorganism proteins: A comparison with soy protein isolate and wheat protein

As a widely acknowledged source of sustainable food protein, there has been limited research on the functional properties of photosynthetic microorganism proteins (PsmPs) applied in food. The nutritional and functional attributes for meat analogue production of Spirulina platensis protein (SpirP), Chlorella pyrenoidosa protein (ChloP), and Schizochytrium sp. protein (SchiP) were investigated and compared with two widely utilized proteins: soy protein isolate (SPI) and wheat protein (WheaP). At a neutral pH, SpirP and SchiP exhibited high emulsifying activities of 69 and 66 m2/g, while ChloP (20 m2/g) was comparable to SPI (15 m2/g) and WheaP (19 m2/g). Their remarkable foaming capacity indicated their potentials to produce meat analogues with fibrous structures. The water absorption capacity of PsmPs (4.4–4.8 g water/g protein) was comparable to WheaP (4.7 g water/g protein), while the oil absorption capacity (3.7–4.4 g oil/g protein) was higher than SPI (2.7 g oil/g protein) and WheaP (3.3 g oil/g protein), implying their potential to produce juicy and tasty meat analogues. Besides, the heat-induced photosynthetic microorganism protein gels had stable structures. In summary, SpirP, ChloP, and SchiP emerge as outstanding protein sources and viable alternatives to SPI for the production of meat analogues.

Safety evaluation of the food enzyme protein-glutamine γ-glutamyltransferase from the non-genetically modified Streptomyces mobaraensis strain M2020197.

The food enzyme protein-glutamine γ-glutamyltransferase (protein-glutamine: amine γ-glutamyltransferase; EC 2.3.2.13) is produced with the non-genetically modified Streptomyces mobaraensis strain M2020197 by Taixing Dongsheng Bio-Tech Co. Ltd. The identity of the production strain and the absence of viable cells could not be established. The food enzyme is intended to be used in eight food manufacturing processes: processing of cereals and other grains for the production of (1) baked products, (2) cereal-based products other than baked; processing of dairy products for the production of (3) fermented dairy products, (4) cheese, (5) dairy desserts; processing of plant- and fungal-derived products for the production of (6) meat analogues, (7) plant-based analogues of milk and milk products; processing of meat and fish products for the production of (8) modified meat and fish products. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 3.498 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 91 mg TOS/kg bw per day. The calculated margin of exposure for each age group was 36 (infants), 26 (toddlers), 50 (children), 99 (adolescents), 115 (adults) and 133 (the elderly). A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood is low. The safety of the food enzyme could not be established given the derived margins of exposure. Therefore, the Panel concluded that the food enzyme could not be considered safe under the intended conditions of use.

Gas-assisted high-moisture extrusion of soy-based meat analogues: Impacts of nitrogen pressure and cooling die temperature on density, texture and microstructure

This study explored the potential of a novel gas-assisted high-moisture extrusion cooking technique to improve the physical quality of meat analogues. Extrusion was performed as a full factorial design at three long cooling die temperatures (DT) (35, 50 and 65 °C) and three nitrogen gas injection pressures (GP) (0, 1 and 2.5 bar). The lowest meat analogue density was observed for the meat analogues produced at the lowest DT and highest GP combination. At the lowest DT, gas injection substantially decreased meat analogue hardness, chewiness and gumminess. X-ray microtomography analyses for meat analogues produced at 2.5 bar gas injection pressure revealed that DT significantly affected bubble sizes with larger and more diverse bubbles in the meat analogues produced at the lowest DT. These microstructural variations indicate that gas-assisted high-moisture extrusion cooking can be fine-tuned to improve the texture and, thus, sensory properties of meat analogues. Industrial relevanceHigh-moisture extrusion cooking is widely used for industrial-scale production of plant-based meat analogues. Manufacturing meat analogues with desired hardness and chewiness without detrimental effects on other characteristics such as color and degree of texturization is still quite challenging using conventional high-moisture extrusion cooking. Gas-assisted high-moisture extrusion cooking, when fine-tuned, has great potential in manipulating end-product texture and color without negatively impacting the degree of protein texturization.

Production of high moisture textured tempeh (fermented soy) protein by single screw cooking extrusion and evaluation of its physicochemical properties and sensory attributes

SummaryThe focus of current research is to produce a high moisture textured vegetable protein (TVP) food by partially substituting soy protein isolate (SPI) with tempeh flour (TF) using a single screw cooking extruder. The influence of the screw speed (SS) on the physicochemical and sensory attributes of the textured tempeh protein (TTP) was compared with textured soy protein (TSP). The SS was adjusted across five distinct levels: 20, 30, 40, 50 and 60 rpm. The moisture, protein, ash, and colour profiles (L*, a*, and b* values) were all observed to improve with an increase in SS. On the contrary, the values of lipids, carbohydrates, water absorption capacity (WAC), and oil absorption capacity (OAC), along with textural profiles decreased. The texture profile values demonstrate a decreased value with the increase in SS. Screw speed influenced the fibrous structure of TTP. However, the visual surface and microstructure of TTP were similar to TSP. The TTP with SS 40 rpm exhibited the highest level of acceptability on sensory attributes. It is anticipated that tempeh will replace soy protein in the production of meat analogues due to its cost‐effectiveness, positive taste profile, high nutritional content, potential for mass production and widespread worldwide consumption.

Effect of fiber properties and orientation on the shear rheology and Poynting effect in meat and meat analogues

The development of plant-based meat analogues is an important aspect of the transition towards using more plant proteins. Production of such products with texture (and rheology) adequate for consumer acceptance like meats is a great challenge. However, there is a current lack in quantitative methods to compare whole cut meats and plant-based analogues that also consider its fibrous structures. We tackled this problem by combining non-linear shear rheology and shear-induced normal stress measurements on whole cut meats (beef and chicken) and plant-based fibrous model systems for meat analogues (soy and pea protein isolates combined with wheat gluten). We found different response in the linear viscoelastic regime for different samples, and the non-linear viscoelastic regime provided a deeper understanding into the role of structural components. Meat samples showed rearrangements at small strains and lower energy dissipation, higher intracycle strain stiffening, and a larger normal stress response at large strains than plant-based fibrous products, due to more elastic fibers. The plant-based fibrous products behave more solid-like until a larger strain, but the fibrous structures break down at large deformations resulting in higher energy dissipation, and show a lower normal stress response than meat. We therefore explore the importance of fiber properties and orientation on the nonlinear rheology of fibrous model systems for meat analogues, and provide a robust methodology to quantitatively compare different mechanical responses of meat and plant-based fibrous meat analogues. These results thereby allow comparison and tuning mechanical responses of plant-based meat analogue products towards real meat.

The Safety of Soy Leghemoglobin Protein Preparation Derived from Pichia pastoris Expressing a Soy Leghemoglobin Gene from Glycine max: In Vitro and In Vivo Studies.

Soy leghemoglobin (LegH) protein derived from soy (Glycine max) produced in Pichia pastoris (reclassified as Komagataella phaffii) as LegH Prep is a novel food ingredient that provides meat-like flavor and aroma to plant-derived food products. The safety of LegH Prep has been previously assessed in a battery of in vivo and in vitro testing and found no adverse effects under the conditions tested. In this new work, we present the results of new in vivo and in vitro tests evaluating the safety of LegH Prep. LegH Prep was nonmutagenic in a bacterial reverse mutation assay and nonclastogenic in an in vitro micronucleus assay in human lymphocytes. Systemic toxicity was evaluated in the 90 day dietary study in male and female Sprague-Dawley® rats that included a 28 day recovery period. The study resulted in no animal deaths associated with the administration of LegH Prep at the highest dose (90,000 ppm). There were no significant adverse clinical or physical changes attributed to LegH Prep administration, and no observed adverse effects on either male or female rats over the course of the 28 day recovery phase study. The new 90 day dietary toxicity study established a no observed adverse effect level (NOAEL) of 4798.3 and 5761.5 mg/kg/day, the maximum level tested for male and female rats, respectively. Thus, the results of the studies demonstrate that under the conditions tested, LegH Prep is not toxic for consumption in meat analog products.

Interaction mechanism of pea proteins with selected pyrazine flavors: Differences in alkyl numbers and flavor concentration

The mechanism of pea protein (PPI) adsorbing flavor components of cooked beef (pyrazine flavor compounds with different concentrations and different numbers of alkyl groups) was researched by spectroscopic and molecular docking approaches. The binding ability results showed that the concentration of pyrazines and the number of alkyl groups in pyrazine strongly influenced the adsorbing ability of PPI. The binding ability of PPI to the pyrazines decreased in the order 2,3,5-trimethyl-pyrazine (TRP) > 2,5-dimethyl pyrazine (DP) > 2-methylpyrazine (MP). The increase in the concentration of pyrazine flavor compounds promoted the enhancement of the adsorption capacity of PPI. Fluorescence and time-resolved fluorescence analysis showed that different molecular structures caused by the amount of alkyl groups on a pyrazine ring showed different quenching types: MP and DP were mainly subjected to static quenching, and TRP with more alkyl groups was mainly subjected to dynamic quenching. During the adsorption of pyrazine flavor compounds, the structure on the peptide bond of pea protein is destroyed. The conformation of pea protein expanded gradually, and the protein changed from ordered structure to disordered structure with lower ΔH. The interactions between pyrazine and pea protein were spontaneous from thermodynamic analysis. Combined with the results of molecular docking, hydrophobic interactions were dominant in the noncovalent interactions between MP and pea protein, whereas hydrogen bonding was dominant between DP/TRP and pea protein. TRP with more alkyl groups could generate new interactions with PPI (π-π stacking interaction) to improve the adsorption capacity of PPI. Pyrazine with more alkyl groups showed a stronger binding force with pea protein to improve the ability of pea protein to adsorb pyrazine flavor compounds, and they displayed different fluorescence quenching mechanisms. This study could provide a theoretical basis for flavor selection and control in the production of pea protein-based meat analogs and thus improve the overall flavor of plant protein-based meat analog products.

Formation mechanism of yeast-soy protein extrudates during high-moisture extrusion and their digestive properties

Yeast protein (YP) has generated significant interest due to its potential for high production efficiency and nutritional value. This study investigated the effects of YP ratios (0–50%) on the formation mechanism of extrudates prepared by YP and soy protein isolate (SPI) during high-moisture extrusion and their in vitro dynamic digestive properties. Extrudates containing 40% YP had the most abundant fiber structures. Combined segmental sampling and closed cavity rheometer (CCR) simulated the extrusion process (mixing, melting, cooling, and extrudate) found that YP was dispersed throughout the SPI network structure in both the mixing and melting zones, and YP as a separate phase transformed SPI into a “mushy” state, facilitating the development of intermolecular forces and promoting the reconstruction of the protein network in the cooling zone. Additionally, in vitro dynamic gastrointestinal digestion has shown that extrudates with high YP content had higher gastric emptying rates and produced digestates with smaller particles. Extrudates containing 30% YP exhibited the highest essential amino acid index (EAAI). Overall, this finding provides a promising strategy for production of meat analogues with high quality using yeast protein.

Plant based meat alternative, from cradle to company-gate: A case study uncovering the environmental impact of the Swedish pea protein value chain

Dry-fractioned pea protein concentrate can be moulded into meat-analogue products, and understanding the environmental impact and hot spots of this expanding industry segment could pave the road to broader adoption of these protein sources. Hence, this research measures the environmental performance of a green pea protein supply chain in southern Sweden that processes pea protein concentrate into pea protein sausages. A cradle-to-factory-gate life-cycle assessment was performed. 1 kg of pea protein concentrate at 46% and 1 kg of pea protein sausages were chosen as functional units, while ReCiPe 2016 v1.1 Midpoint E was utilized to calculate 18 impact categories. Economic allocation was applied to pea protein processing, and mass allocation to sausage production, using 2021/22 data from Swedish companies. For 1 kg of pea protein concentrate of 46%, cultivation contributes to 41–99% of the total impact considering all 18 impact categories, while processing 1–59%. The climate impact was 1.91 kg CO2eq/kg pea protein concentrate (1.54 from the cultivation step and 0.37 from the processing step). For 1 kg of pea protein sausages, cultivation and sausage production contributed together between 32% and 78% to the total impacts. The climate impact was 1.0 kg CO2eq/kg sausage. Comparing the climate impacts of sausage ingredients, rapeseed oil and spices contributed significantly. For the sausage production stage, electricity and natural gas contributed the most. The results for climate impact are in the same range as for similar plant-based products, although the range reported in literature is wide. Green pea cultivation, sausage production and ingredients contributed all significantly. The results highlight the need to address the choice of ingredients when formulating the final product. The choice of allocation method had a significant impact on the results. Mass allocation resulted in 6 times lower impacts for the pea protein concentrate compared to economic allocation.

Towards a Better Understanding of Texturization during High-Moisture Extrusion (HME)-Part II: Characterization of Thermophysical Properties of High-Moisture Meat Analogues.

It is crucial to determine the thermophysical properties of high-moisture extruded samples (HMESs) to properly understand the texturization process of high-moisture extrusion (HME), especially when the primary objective is the production of high-moisture meat analogues (HMMAs). Therefore, the study's aim was to determine thermophysical properties of high-moisture extruded samples made from soy protein concentrate (SPC ALPHA® 8 IP). Thermophysical properties such as the specific heat capacity and the apparent density were experimentally determined and further investigated to obtain simple prediction models. These models were compared to non-HME-based literature models, which were derived from high-moisture foods, such as soy-based and meat products (including fish). Furthermore, thermal conductivity and thermal diffusivity were calculated based on generic equations and literature models and showed a significant mutual influence. The combination of the experimental data and the applied simple prediction models resulted in a satisfying mathematical description of the thermophysical properties of the HME samples. The application of data-driven thermophysical property models could contribute to understanding the texturization effect during HME. Further, the gained knowledge could be applied for further understanding in related research, e.g., with numerical simulation studies of the HME process.

Meat and plant-based meat analogs: Nutritional profile and in vitro digestion comparison

Plant-based meat analogs have received considerable attention as alternatives to genuine meat. In the current work, the nutritional profile and in vitro digestion characteristics of meat (beef, chicken, and pork) and four types of commercial plant-based meat analog products from companies, were investigated and compared. The protein level of meat was higher than 25 g/100 g, and the protein content of chosen plant-based meat analogs was between 14.1 g/100 g and 19.8 g/100 g. Plant-based meat analogs contained a certain amount of carbohydrates and dietary fiber, while they were not found in meat. The average sodium content of the chosen meat analogs was about 7.9 times higher than that of meat. Furthermore, plant-based meat analogs have lower cholesterol and higher polyunsaturated fatty acids. Compared to meat, plant-based meat analogs showed lower protein digestibility and released fewer bioactive peptides after in vitro digestion. These findings would provide significant information for the quality-directed regulation of plant-based meat analog products, and promote the development of plant-based food industry.

Influences of Spices on the Flavor of Meat Analogs and Their Potential Pathways.

This study evaluated the correlation between the sensory characteristics and spices of 50 commercial meat analogs and selected 4 spices to improve the flavor characteristics of soy protein concentrate (SPC) extrudates. Volatile compounds in extrudates and commercial meat analogs were investigated using headspace solid-phase microextraction and gas chromatography-mass spectrometry. The total concentrations of off-flavor volatile compounds in commercial products decreased with an increasing degree of processing. Furthermore, after adding spices during extrusion, the concentrations of volatile compounds such as aldehydes, alcohols, and furans related to thermal treatment decreased by approximately 5-39%, 5-15%, and 11-56%, respectively. Among them, compounds such as nonanal, 2-pentlyufuran, and 1-octen-3-ol, typical off-flavors in soy-based food, decreased by 8-42%, 11-55%, 2-52%, respectively. The correlation analysis between the antioxidative abilities of spices and volatile compounds showed that the contents of total phenolics were negatively correlated with the contents of ketones and alcohols in extrudates (p < 0.001). Moreover, the aroma-active compounds in extrudates were changed. More pleasant compounds, including alkanes and olefins, were observed by adding different spices as well. Especially in black pepper treated extrudates, the OAV value of off-flavor volatile compounds such as hexanal, octanal, 2-pentlyfuran decreased. In conclusion, the addition of spices can reduce off-flavor compounds related to thermal reactions, such as oxidation and the Maillard reaction, and impart newly pleasant flavors to extrudates during the extrusion of SPC. It is important to explore new methods that can be used to improve the flavor of extrudates so that consumers' preferences of meat analog products can be improved.