Composition and functional properties of protein isolates obtained from commercial legumes grown in northern Spain

Decoding the Duality of Antinutrients: Assessing the Impact of Protein Extraction Methods on Plant-Based Protein Sources

This review aims to provide an updated overview of the effects of protein extraction/recovery on antinutritional factors (ANFs) in plant protein ingredients, such as protein-rich fractions, protein concentrates, and isolates. ANFs mainly include lectins, trypsin inhibitors, phytic acid, phenolic compounds, oxalates, saponins, tannins, and cyanogenic glycosides. The current technologies used to recover proteins (e.g., wet extraction, dry fractionation) and novel technologies (e.g., membrane processing) are included in this review. The mechanisms involved during protein extraction/recovery that may enhance or decrease the ANF content in plant protein ingredients are discussed. However, studies on the effects of protein extraction/recovery on specific ANFs are still scarce, especially for novel technologies such as ultrasound- and microwave-assisted extraction and membrane processing. Although the negative effects of ANFs on protein digestibility and the overall absorption of plant proteins and other nutrients are a health concern, it is also important to highlight the potential positive effects of ANFs. This is particularly relevant given the rise of novel protein ingredients in the market and the potential presence or absence of these factors and their effects on consumers' health.

Heat-Induced Gelation of Chickpea and Faba Bean Flour Ingredients

This study aimed to investigate the gelling behavior of faba bean (FB) and chickpea (CP) flour between 10 and 20% (w/w) concentration at pH 3.0, 5.0, and 7.0. Both sources formed at pH 3.0 and 5.0 self-standing gels with 12% (w/w) of flour, while 16% (w/w) of flour was required to obtain a gel at pH 7.0. During gelling between 40 and 70 °C, a sharp increase of the elastic modulus G' was observed in both flours, mainly due to water absorption and swelling of the starch, one of the major constituents in the ingredients. Increasing the temperature at 95 °C, G' increased due to the denaturation of globulins and therefore the exposure of their internal part, which allowed more hydrophobic interactions and the formation of the gel. After cooling, both FB and CP gels displayed a solid-like behavior (tan δ ranging between 0.11 and 0.18) with G' values at pH 3.0 and 5.0 significantly (p < 0.05) higher than those at pH 7.0, due to the lower electrostatic repulsions at pHs far from the isoelectric point. The rheological properties were supported by the water binding capacity values, confirming the better gels' strength described by rheological analysis. These results will enhance our understanding of the role of legume flours in formulating innovative and sustainable food products as alternatives to animal ones.

Effect of Faba Bean Isolate and Microbial Transglutaminase on Rheological Properties of Pork Myofibrillar Protein Gel and Physicochemical and Textural Properties of Reduced-Salt, Low-Fat Pork Model Sausages

The study was performed to determine the effect of faba bean protein isolate (FBPI) alone or in combination with microbial transglutaminase (MTG) on the rheological properties of pork myofibrillar protein gel (MPG), and physiochemical and textural properties of reduced-salt, low-fat pork model sausages (LFMSs). The cooking yields of MPGs with MTG or FBPI alone decreased and increased, respectively. However, the combination of FBPI and MTG was similar to the control (CTL) without FBPI or MTG. Gel strength values of MPG added with both FBPI and MTG were higher than treatments with FBPI or MTG alone. The hydrophobicity values of CTL were lower than those of MPG with FBPI alone, whereas the addition of MTG decreased the hydrophobicity of MPGs. The incorporation of FBPI alone or in combination with MTG decreased sulfhydryl groups (p<0.05). Shear stress values of MPGs with MTG tended to be higher than those of non-MTG treatments at all shear rates, and the addition of FBPI into MPGs increased shear stress values. Reduced-salt (1.0%) LFMSs with FBPI alone or combined with MTG had both lower cooking loss and expressible moisture values than those of CTL and similar values to the reference sample (REF, 1.5% salt). Textural properties of reduced-salt LFMSs with FBPI or MTG were similar to those of REF. These results demonstrated that the combination of FBPI and MTG could improve the water binding capacity and textural properties of pork MPGs and LFMSs and might be suitable for application in the development of healthier meat products.

Effects of faba bean protein isolate on rheological properties of pork myofibrillar protein gels and quality characteristics of pork low-fat model sausages

BACKGROUND

This study aimed to assess the effect of faba bean (Vicia faba L.) protein isolate (FBPI) on the rheological properties of pork myofibrillar protein gels (MPGs) and the quality characteristics of pork low-fat model sausages (LFMSs).

RESULTS

Pork MPGs with 5 or 10 g kg-1 FBPI had higher cooking yield, gel strength, and viscosity than controls. The addition of FBPI to MPGs increased the protein surface hydrophobicity and decreased sulfhydryl groups. Adding FBPI to MPGs changed the protein profile and microstructure. The cooking loss and expressible moisture of LFMSs with 5, 10, or 15 g kg-1 FBPI were lower than those of controls and showed similar results to those with 15 g kg-1 soy protein isolate (SPI). Hardness values of LFMSs with FBPI and SPI were no different, and were higher than those of controls.

CONCLUSION

The addition of FBPI potentially improves rheological properties of MPGs and the functional properties of LFMSs, including water-holding capacity and textural properties. © 2024 Society of Chemical Industry.

Properties of texturized protein and performance of different protein sources in the extrusion process: A review

The need for protein is increasing due to the rapid growth of the global population. However, conventional animal meat production has caused severe environmental, land usage, and other issues. Meat substitutes can provide consumers with a high-quality alternative to protein. Texturized protein (TP) is a critical ingredient in meat substitutes and is mainly obtained through extrusion processing. Therefore, this review first discussed the essential physical properties of TP, including appearance and structure, water-holding capacity (WHC) and oil-holding capacity (OHC), texture, and sensory properties. The performance of plant and novel source proteins in extrusion processing is also summarized. The properties of the desired TP should be considered first before extrusion processing. Under different extrusion parameters, proteins from the same source can exhibit varying properties. Although the novel source proteins can adversely affect TP quality, their high yield and environmental protection are worthy of further study. This paper aims to review the impact of proteins from different sources on the properties of TP during the extrusion process and discuss practical research methods for TP.

Nordic Crops as Alternatives to Soy-An Overview of Nutritional, Sensory, and Functional Properties

Soy (Glycine max) is used in a wide range of products and plays a major role in replacing animal-based products. Since the cultivation of soy is limited by cold climates, this review assessed the nutritional, sensory, and functional properties of three alternative cold-tolerant crops (faba bean (Vicia faba), yellow pea (Pisum sativum), and oat (Avena sativa)). Lower protein quality compared with soy and the presence of anti-nutrients are nutritional problems with all three crops, but different methods to adjust for these problems are available. Off-flavors in all pulses, including soy, and in cereals impair the sensory properties of the resulting food products, and few mitigation methods are successful. The functional properties of faba bean, pea, and oat are comparable to those of soy, which makes them usable for 3D printing, gelation, emulsification, and extrusion. Enzymatic treatment, fermentation, and fibrillation can be applied to improve the nutritional value, sensory attributes, and functional properties of all the three crops assessed, making them suitable for replacing soy in a broad range of products, although more research is needed on all attributes.

Associating Compositional, Nutritional and Techno-Functional Characteristics of Faba Bean (Vicia faba L.) Protein Isolates and Their Production Side-Streams with Potential Food Applications

Faba beans (Vicia faba L.) show exciting prospects as a sustainable source of protein and fibre, with the potential to transition to a more sustainable food production. This study reveals the compositional, nutritional and techno-functional characteristics of two protein isolates from faba beans (Vicia faba L.), a high-starch fraction and a high-fibre side-stream. During the analysis of those four ingredients, particular attention was paid to the isolates' protein profile and the side-streams' carbohydrate composition. The isoelectric precipitated protein isolate 1 showed a protein content of 72.64 ± 0.31% DM. It exhibited low solubility but superior digestibility and high foam stability. High foaming capacity and low protein digestibility were observed for protein isolate 2, with a protein content of 71.37 ± 0.93% DM. This fraction was highly soluble and consisted primarily of low molecular weight proteins. The high-starch fraction contained 83.87 ± 3.07% DM starch, of which about 66% was resistant starch. Over 65% of the high-fibre fraction was insoluble dietary fibre. The findings of this study provide a detailed understanding of different production fractions of faba beans, which is of great value for future product development.

Encapsulation of Cumin (Cuminum cyminum L.) Seed Essential Oil in the Chickpea Protein-Maltodextrin Matrix

Isoelectrically precipitated chickpea protein isolate (CPI) and its combination with maltodextrin (MD) were investigated for the ability to form and stabilize cumin seed oil emulsions. Solubility, net surface charge, emulsion activity/stability indices, and creaming stability of CPI at a pH of 3.0-9.0 were evaluated. Optimum conditions for minimum cream separation were identified as: 0.19% CPI and 6.83% oil concentrations. Cumin (Cuminum cyminum L.) seed essential oil was microencapsulated within the CPI-MD matrix via spray drying. Effects of CPI-MD matrix formulation on the physicochemical characteristics and volatile composition of the microencapsules were investigated. CPI-MD matrices had positive effects on microcapsule properties such as relatively lower surface oil, higher encapsulation efficiency (EE), and oil retention. Approximately 86.6-96.4% oil retention and 90.9-98.4% EE were achieved. Optimum conditions for maximized oil retention (92.9%) and EE (98.6%) were identified as: 2.1% CPI, 14.8% essential oil, and 35% MD. GC-MS analysis of microcapsules was carried out to determine the changes in volatile composition during spray drying. Cymene, α-pinene, β-pinene, sabinene, terpinene, terpineol, phellandrene, and cumin aldehyde were determined as the major components. Optimized design showed the highest EE and minimal changes in the volatile composition of cumin seed essential oil.

The Impact of Dehulling and Germination on the Physiochemical, Protein Solubility and Water and Oil Holding Capacities of Yellow Eye Bean (Phaseolus vulgaris L.) Protein Concentrates

Pulse varieties including Yellow Eye (YE) beans (Phaseolus vulgaris L.) are a rich source of protein (~26.5%) that can be utilized to create value-added protein concentrates. Pre-treatments including dehulling and germination have been shown to be effective at improving the nutritional and functional properties of extracted protein concentrates. However, the composition and functionality of these protein concentrates can vary depending on the pre-treatments and the method of extraction used (salt vs. alkaline). Furthermore, little is known about the impact of combining these different processing methods on the properties of YE bean protein concentrates. The objective of this study was to evaluate how germination and dehulling pre-treatments individually and when combined influence protein extraction efficiency, physiochemical properties (surface hydrophobicity and intrinsic fluorescence), and the functionality (solubility, oil and water holding capacities) of salt and alkaline extracted protein concentrates. Compared to the salt extracted concentrates, the alkaline protein concentrates exhibited higher protein recovery yields (16–23% vs. 43–56%) respectively. Conversely, the salt extracted protein concentrates exhibited superior functional properties as observed by improved water holding capacities and less variation in their solubilities at different pH values (4 to 10). When the pre-treatments were combined, the salt extracted concentrates exhibited improved extraction efficiencies and improved hydrophobicity and intrinsic fluorescence, whereas the opposite trend was observed in the alkaline protein concentrates. These observations were attributed to differences in the protein content and composition of the salt vs. alkaline protein concentrates. Overall, these findings suggest that dehulling and germination are potential processing methods that may be used to improve the physiochemical characteristics of salt extracted protein concentrates from yellow eye beans. Future research may investigate the potential application of these ingredients in different food formulations.

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.

In vitro digestion of protein and starch in sponge cakes formulated with pea (Pisum sativum L.) ingredients

This study investigated the in vitro digestion of purified pea fractions (protein isolate and starch) in sponge cakes when compared to unrefined pea flour and to the whole wheat flour and purified maize starch commonly used in the food industry. Proteins in the wheat cake were hydrolysed more rapidly than those in cakes made with either pea flour or a combination of pea proteins and purified starch. In absolute terms, however, more readily bioaccessible protein was released from these pea cakes (by around 40%). By contrast, cakes containing wheat flour or maize starch were more susceptible to amylolysis compared to those based on pea starch in the form of the purified ingredient or whole flour. This could be attributed to a higher proportion of amylose and resistant starch in the pea cakes as well as structural characteristics that might have decelerated enzyme-substrate interactions. Interestingly, similar digestion patterns were observed regarding the purified pea ingredients and unrefined whole pea flour. It was therefore concluded that pea ingredients, and particularly the less purified and thus more sustainable whole pea flour, are promising plant-based alternatives for use in gluten-free baked products.

Effect of Different Technological Factors on the Gelation of a Low-Lectin Bean Protein Isolate

Gelling ability of a bean protein isolate (BPI) obtained from a naturally low-lectin variety (Phaseolus vulgaris var. Almonga) was analysed. For that purpose differences on gels processing: concentration (14% and 17%), salt addition (0 and 2%), and pH (6.5 -lot A- and 7 -lot B), were studied to obtain suitable colour, mechanical and viscoelastic properties for making appropriate meat and seafood analogues. Gelation at pH 7 at both 14 and 17% BPI concentrations, produced less rigid, more flexible, time-stable and cohesive gel networks. Colour of the resulting gels was white enough to be considered as an adequate base for making plant-based analogues. The content of total galactoside, inositol phosphates and trypsin inhibitors (bioactive compounds) present in one serving (100 g) of these BPI gels were up to 0.80 mg/g, 8.06 mg/g and 239 TIUs, respectively.

Functional Performance of Plant Proteins

Increasingly, consumers are moving towards a more plant-based diet. However, some consumers are avoiding common plant proteins such as soy and gluten due to their potential allergenicity. Therefore, alternative protein sources are being explored as functional ingredients in foods, including pea, chickpea, and other legume proteins. The factors affecting the functional performance of plant proteins are outlined, including cultivars, genotypes, extraction and drying methods, protein level, and preparation methods (commercial versus laboratory). Current methods to characterize protein functionality are highlighted, including water and oil holding capacity, protein solubility, emulsifying, foaming, and gelling properties. We propose a series of analytical tests to better predict plant protein performance in foods. Representative applications are discussed to demonstrate how the functional attributes of plant proteins affect the physicochemical properties of plant-based foods. Increasing the protein content of plant protein ingredients enhances their water and oil holding capacity and foaming stability. Industrially produced plant proteins often have lower solubility and worse functionality than laboratory-produced ones due to protein denaturation and aggregation during commercial isolation processes. To better predict the functional performance of plant proteins, it would be useful to use computer modeling approaches, such as quantitative structural activity relationships (QSAR).

Air-classified faba bean protein fraction as a substitute to soybean meal in pelleted and extruded broiler diets

1. The hypothesis that air-classified faba bean protein fraction (FBP) can replace soybean meal (SBM) in pelleted or extruded broiler diets without adverse effect on performance or nutrient digestibility was tested.2. At 17 d of age, male broilers were randomly distriibuted among four dietary treatments consisting of either SBM or FBP (main dietary protein source) and pelleting or extrusion as processing methods. Treatments had 10 replicate pens containing five birds each.3. Compared to SBM, birds fed FBP had significantly lower feed intake, less weight gain and had poorer feed conversion.4. Pellet durability was high (above 92%) for all diets. In pelleted diets, FBP was harder than SBM whereas extruded diets had similar hardness. Pelleting increased water stability compared to extrusion. FBP diets were more water stable than the SBM diets.5. Gizzard content weight was 2.2-fold higher (P = 0.002) for birds given FBP compared to those fed SBM. The weight of the jejunum and ileum with contents was 1.4-fold lower for the FBP diets, and this effect was larger (P < 0.05) for the extruded FBP diet.6. Birds fed FBP diets had significantly higher nitrogen digestibility in the lower jejunum and ileum compared to those given SBM diets, while the starch digestibility coefficient was above 0.980 in all treatments.7. The high nutrient digestibility of FBP diets indicates that the poor performance of the FBP group was due to lower feed intake which was not explained by the differences in pellet durability or hardness. The reduced palatability of the FBP and the longer retention of the FBP diets in the upper gut are more likely to have depressed feed intake.

A new trend among plant-based food ingredients in food processing technology: Aquafaba

In the new century, the most fundamental problem on a global scale is hunger and poverty reduction is one of the primary goals set by the United Nations. Currently, it is necessary to increase agricultural activities and to evaluate all agricultural products rich in nutrients without loss in order to feed the hungry population in the world. Considering that one of the most important causes of hunger in the world is inadequate access to protein content, legumes are one of the most valuable nutritional resources. In order to ensure the sustainability of legumes, alternative new ways of recycling their wastes are sought based on these multiple functions. For this purpose, recycling legume cooking waters to be used as food raw materials in various processes means reducing food waste. Recovery of nutritional components in legumes is also beneficial in vegan and vegetarian diets. In this review study, the importance of legumes in terms of global needs, their importance in terms of nutrition, the methods of obtaining the protein content of legumes, the functional properties of these proteins in the field of food processing, the gains of the evaluation and recovery of legume cooking water (Aquafaba), especially waste, were discussed.

Aquafaba from Korean Soybean I: A Functional Vegan Food Additive

The substitution of animal-based foods (meat, eggs, and milk) with plant-based products can increase the global food supply. Recently, pulse cooking water (a.k.a. aquafaba) was described as a cost-effective alternative to the egg in gluten-free, vegan cooking and baking applications. Aquafaba (AQ) forms stable edible foams and emulsions with functional properties that are like those produced by whole egg and egg white. However, the functional ingredients of AQ are usually discarded during food preparation. In this study, Korean-grown soy (ver. Backtae, Seoritae, and Jwinunikong) and chickpea were used to produce AQ. Two approaches were compared. In the first, seed was cooked at an elevated pressure without presoaking. In the second, seed was soaked, then, the soaking water was discarded, and soaked seed was cooked at an elevated pressure. Both approaches produced a useful emulsifier, but the latter, with presoaking, produced a superior product. This approach could lead to a process that involves a small number of efficient steps to recover an effective oil emulsifier, produces no waste, and is cost-effective. The AQ product from Backtae (yellow soybean) produced emulsions with better properties (90%) than AQ produced from other cultivars and produced more stable food oil emulsions. This study will potentially lead to gluten-free, vegan products for vegetarians and consumers with animal protein allergies. This is the first report of the efficient production of AQ, an egg white substitute derived from cooked soybean of known cultivars.

Legumes as Functional Food for Cardiovascular Disease

Legumes are an essential food source worldwide. Their high-quality proteins, complex carbohydrates, dietary fiber, and relatively low-fat content make these an important functional food. Known to possess a multitude of health benefits, legume consumption is associated with the prevention and treatment of cardiovascular diseases (CVD). Legume crude protein isolates and purified peptides possess many cardiopreventive properties. Here, we review selected economically valued legumes, their taxonomy and distribution, biochemical composition, and their protein components and the mechanism(s) of action associated with cardiovascular health. Most of the legume protein studies had shown upregulation of low-density lipoprotein (LDL) receptor leading to increased binding and uptake, in effect significantly reducing total lipid levels in the blood serum and liver. This is followed by decreased biosynthesis of cholesterol and fatty acids. To understand the relationship of identified genes from legume studies, we performed gene network analysis, pathway, and gene ontology (GO) enrichment. Results showed that the genes were functionally interrelated while enrichment and pathway analysis revealed involvement in lipid transport, fatty acid and triglyceride metabolic processes, and regulatory processes. This review is the first attempt to collate all known mechanisms of action of legume proteins associated with cardiovascular health. This also provides a snapshot of possible targets leading to systems-level approaches to further investigate the cardiometabolic potentials of legumes.

Improving the Functionality of Proso Millet Protein and Its Potential as a Functional Food Ingredient by Applying Nitrogen Fertiliser

Nitrogen is required for proso millet growth and has a critical influence on yield and quality. However, the effect of nitrogen fertilisation on proso millet protein properties remains unclear. This study aimed to investigate how nitrogen fertiliser treatment (180 kg/hm²) affects the structural and functional properties of proso millet protein. In comparison with the control group (N0), nitrogen fertiliser treatment loosened the dense structure of the protein and presented a larger particle size. Nitrogen treatment did not change the main subunit composition, and β-sheet and α-helix were the main secondary structures of proso millet protein based on Fourier transform infrared spectroscopy. In addition, nitrogen fertiliser treatment improved the content of hydrophobic amino acids and β-sheet proportion from proso millet protein, and high water/oil absorption capacity and thermal stability was observed, but the solubility, emulsion stability and foaming properties from proso millet protein decreased. Proso millet proteins exhibited high amino acid content and good functional properties, including solubility, foaming capacity and emulsifying properties, especially the w139 variety. Results show that proso millet protein has great potential for food applications. The above results provide useful information for the food industry to determine emerging gluten-free protein resources.

Effect of Acetylation on Physicochemical and Functional Properties of Commercial Pumpkin Protein Concentrate

The purpose of the present study was to determine the effects of acetylation with different doses of acetic anhydride on the chemical composition and chosen functional properties of commercial pumpkin protein concentrate (PPC). The total protein content decreased as compared to unmodified samples. Electrophoretic analysis revealed that in the acetylated pumpkin protein, the content of the heaviest protein (35 kDa) decreased in line with increasing concentrations of modifying reagent. Acetylation of PPC caused a significant increase in water-binding and oil-absorption capacity and for emulsifying properties even at the dose of 0.4 mL/g. Additionally, an increase in foaming capacity was demonstrated for preparations obtained with 2.0 mL/g of acetic anhydride, whereas acetylation with 0.4 and 1.0 mL/g caused a decrease in protein solubility as compared to native PPC.

Functional and Rheological Properties of Vicia faba L. Protein Isolates

A protein isolate (85.5%) was obtained from the Vicia faba L. seeds. The main protein fraction, typical for the seeds of this plant, was found to be most numerous: Legumin (35 kDa) and Vicilin (45 kDa). The hydrodynamic and surface properties of isolate aqueous solutions were studied with the help of dynamic light scattering, ζ-potential, and tensometry in a wide range of concentrations and pH conditions. Selected functional properties, like foaming and emulsifying abilities, were studied. An increase of water solubility was shown with a raising pH, as well as a water holding capacity (WHC). The protein isolate showed a tendency to decrease the surface tension of water solutions, with high hydrophobicity and a negative charge of the isolate enhancing the foaming and emulsifying properties. The analysis of the concentration and the pH influence on selected functional properties indicated alkaline conditions as favorable for good foaming and emulsifying properties of the isolate and affected on their rheological properties.

Heat induced gelation of pulse protein networks

This study examines the effect of salts (0.5 M NaCl or 0.25 M CaCl₂) and protein concentration (7.5-15%) on the gel-forming abilities of lentil (LPC), yellow pea (YPC), and faba bean (FPC) protein concentrates formed at pH 7.0. The surface hydrophobicity of YPC (84.8 arbitrary units, a.u.) was found to be lower than LPC (147.2 a.u.) and FPC (135.0 a.u.). In contrast, the surface charge for LPC, YPC, and FPC was -37.8, -28.4, and -29.3 mV, respectively. The Lg/Vn ratio of YPCs was determined as 0.65 followed by LPC (0.57) and FPC (0.41). The presence of salts reduced the least gelling concentration. LPC and FPC also appeared to have a more ordered structure than YPC as evident by CLSM. The network appeared more ordered as the protein concentration increased or in the presence of NaCl or CaCl₂ according to CLSM and synchrotron based micro computed tomography (µCT).

Comparison of Bioactive Compounds Content and Techno-Functional Properties of Pea and Bean Flours and their Protein Isolates

Recently, legume protein isolates are increasingly of interest as ingredients for the food industry; however, in spite of their health benefits, there is a limited information about the presence of bioactive compounds in the protein isolates. The objective of this study was to establish the phytochemical composition and selected techno-functional properties of pea and bean flours and their protein isolates obtained applying different drying methods. Regarding proximate composition, bean flour contained higher amounts of total protein (23%) and fat (44%) than pea flour; bean protein isolate (BPI) contained higher total and soluble protein, fat and starch than the pea protein isolate (PPI). Both protein isolates showed a similar emulsifying capacity (around 27%). Emulsion stability and foaming capacity were higher in the PPI (around 36%). Bean flour contained lower amounts of α-galactosides (31.64 mg/g) but a higher trypsin inhibitors content (21.95 TIU/mg) than pea flour. The preparation procedure of the protein isolates affected the bioactive compound content. The PPI showed a reduction of inositol phosphates (13%), galactosides (76%), trypsin inhibitors (90%) and total phenolic compounds (35%) compared to its whole flour. The BPI contained higher amounts of inositol phosphates (137%) and total phenolic compounds (135%) than its flour, while it showed a lower content of galactosides (54%) and a similar amount of trypsin inhibitors. Thus, the bioactive compound content and the functional properties studied indicate that protein isolates can be used as ingredients with added-value in the development of new formulated food products, allowing their increasing use in the food industry.

Comparison of Faba Bean Protein Ingredients Produced Using Dry Fractionation and Isoelectric Precipitation: Techno-Functional, Nutritional and Environmental Performance

Dry fractionated faba bean protein-rich flour (FPR) produced by milling/air classification, and faba bean protein isolate (FPI) produced by acid extraction/isoelectric precipitation were compared in terms of composition, techno-functional properties, nutritional properties and environmental impacts. FPR had a lower protein content (64.1%, dry matter (DM)) compared to FPI (90.1%, DM), due to the inherent limitations of air classification. Of the two ingredients, FPR demonstrated superior functionality, including higher protein solubility (85%), compared to FPI (32%) at pH 7. Foaming capacity was higher for FPR, although foam stability was similar for both ingredients. FPR had greater gelling ability compared to FPI. The higher carbohydrate content of FPR may have contributed to this difference. An amino acid (AA) analysis revealed that both ingredients were low in sulfur-containing AAs, with FPR having a slightly higher level than FPI. The potential nutritional benefits of the aqueous process compared to the dry process used in this study were apparent in the higher in vitro protein digestibility (IVPD) and lower trypsin inhibitor activity (TIA) in FPI compared to FPR. Additionally, vicine/convicine were detected in FPR, but not in FPI. Furthermore, much lower levels of fermentable oligo-, di- and monosaccharides, and polyols (FODMAPs) were found in FPI compared to FPR. The life cycle assessment (LCA) revealed a lower environmental impact for FPR, partly due to the extra water and energy required for aqueous processing. However, in a comparison with cow's milk protein, both FPR and FPI were shown to have considerably lower environmental impacts.

Effects of irradiation on the structure and properties of glycosylated soybean proteins

At present, there are few reports on the glycosylation modification of soybean proteins under irradiation. In this paper, a soybean protein isolate and maltose were used as raw materials to prepare a glycosylated soybean protein under gamma-ray treatment to improve the functional properties and evaluate the changes in the structure. The results of analysis of the graft degree, browning index, polyacrylamide gel electrophoresis, infrared spectrum, fluorescence spectrum and ultraviolet spectrum of the modified product showed that the Maillard reaction between the soybean protein isolate and maltose occurred and the structure of the reaction product changed. When the irradiation dose was 7.5 kGy, the solubility of modified products increased by 23 ± 0.21% compared with that of the control group. The foaming property and foam stability increased by 62.5 ± 0.34% and 41 ± 0.47%, respectively. Emulsification, water absorption capacity and fat absorption capacity of glycosylated compounds also increased significantly. Compared with other modification methods, irradiation technology had the advantages of short action time, high efficiency and low cost, and more importantly, its industrial production was easy to implement. This experiment combined irradiation technology with the glycosylation modification method. It was proved that irradiation could promote the Maillard reaction between the soybean protein isolate and maltose, and significantly improve the functional properties of the modified protein, providing theoretical and technical support for expanding the application of the soy protein isolate in the food industry.

Lactic Acid Fermentation as a Pre-Treatment Process for Faba Bean Flour and Its Effect on Textural, Structural and Nutritional Properties of Protein-Enriched Gluten-Free Faba Bean Breads

Lactic acid fermentation could be used as a potential modification tool for faba bean flour to enable its incorporation in boosting the nutritional profile of gluten-free breads. Gluten-free breads made with fermented or unfermented faba bean flours were compared with commercial soy flour. The amounts of faba- and soy-bean flours were adjusted to obtain the same protein content in bread (16%). Both fermented and unfermented faba bean flour resulted in larger bread volume (2.1 mL/g and 2.4 mL/g, respectively) compared to bread made with soybean flour (1.5 mL/g). Breads made with unfermented and fermented faba flour had higher porosity (82% and 72%, respectively) than bread with soy flour (61%). The faba breads also were softer than the soy bread. Fermentation of faba flour prior to bread making significantly increased crumb hardness (584 vs. 817 g). Fermentation increased in vitro protein digestibility (72.3% vs. 64.8%). Essential Amino Acid and Biological Value indexes were significantly higher for breads containing fermented faba flour compared to breads made with unfermented faba and soy flour. The Protein Efficiency Ratio and Nutritional Index increased by fermentation from 33 to 36 and 1.6 to 2.7, respectively. Pre-fermentation of faba bean flour improved the nutritional properties of high-protein, gluten-free faba bread. A sensory panel indicated that fermentation did not affect the crumbliness, evenness of pore size and springiness of breadcrumb.