Legume Proteins Research Articles

Legume Protein Consumption and the Prevalence of Legume Sensitization.

Sensitization and allergy to legumes can be influenced by different factors, such as exposure, geographical background, and food processing. Sensitization and the allergic response to legumes differs considerably, however, the reason behind this is not yet fully understood. The aim of this study is to investigate if there is a correlation between legume protein consumption and the prevalence of legume sensitization. Furthermore, the association between sensitization to specific peanut allergens and their concentration in peanut is investigated. Legume sensitization data (peanut, soybean, lupin, lentil, and pea) from studies were analyzed in relation to consumption data obtained from national food consumption surveys using the European Food Safety Authority (EFSA), Global Environment Monitoring System (GEMS), and What We Eat in America—Food Commodity Intake Database (WWEIA-FCID) databases. Data were stratified for children <4 years, children 4–18 years, and adults. Sufficient data were available for peanut to allow for statistical analysis. Analysis of all age groups together resulted in a low correlation between peanut sensitization and relative peanut consumption (r = 0.407), absolute peanut consumption (r = 0.468), and percentage of peanut consumers (r = 0.243). No correlation was found between relative concentrations of Ara h 1, 2, 3, 6, 7, and 8 in peanut and sensitization to these peanut allergens. The results indicate that the amount of consumption only plays a minor role in the prevalence of sensitization to peanut. Other factors, such as the intrinsic properties of the different proteins, processing, matrix, frequency, timing and route of exposure, and patient factors might play a more substantial role in the prevalence of peanut sensitization.

WRKY transcription factors in legumes

BackgroundWRKY transcription factors, so named because of the WRKYGQK heptapeptide at the N-terminal end, are widely distributed in plants and play an important role in physiological changes and response to biotic and abiotic stressors. Many previous studies have focused on the evolution of WRKY transcription factors in a given plant; however, little is known about WRKY evolution in legumes. The gene expression pattern of duplicated WRKY transcription factors remains unclear.ResultsWe first identified the WRKY proteins in 12 legumes. We found that the WRKYGQK heptapeptide tended to mutate into WRKYGKK. The Q site in WRKYGQK preferentially mutated, while W, K, and Y were conserved. The phylogenetic tree shows that the WRKY proteins in legumes have multiple origins, especially group IIc. For example, WRKY64 from Lupinus angustifolius (LaWRKY64) contains three WRKY domains, of which the first two clustered together in the N-terminal WRKY domain of the group I WRKY protein, and the third WRKY domain grouped in the C-terminal WRKY domain of the group I WRKY protein. Orthologous WRKY genes have a faster evolutionary rate and are subject to constrained selective pressure, unlike paralogous WRKY genes. Different gene features were observed between duplicated WRKY genes and singleton WRKY genes. Duplicated Glycine max WRKY genes with similar gene features have gene expression divergence.ConclusionsWe analyzed the WRKY number and type in 12 legumes, concluding that the WRKY proteins have multiple origins. A novel WRKY protein, LaWRKY64, was found in L. angustifolius. The first two WRKY domains of LaWRKY64 have the same origin. The orthologous and paralogous WRKY proteins have different evolutionary rates. Duplicated WRKY genes have gene expression divergence under normal growth conditions in G. max. These results provide insight into understanding WRKY evolution and expression.

On the thermal behavior of protein isolated from different legumes investigated by DSC and TGA.

Pea, lentil, faba bean, chickpea and bean proteins are potentially renewable raw materials for bioplastic production that can be obtained from agricultural waste. Plastics are usually processed under heating, and thus thermal stability is a mandatory requirement for the application. In this study, the thermal behavior of several legume protein isolates at different purity degrees was investigated. The thermal stability of proteins extracted from legumes was maximum for chickpeas and minimum for beans and decreased with decreasing protein purity in the range 30-88%. A similar dependence on purity was observed for the glass transition temperature. On the contrary, the denaturation temperature was found not to depend on sample purity and origin and was lower than the degradation temperature only in the case of protein samples with purity higher than 60%. Proteins from legumes are suitable to produce thermoplastic biopolymeric materials if isolated at purity higher than 60%. In fact, under this circumstance, they can be denaturized without degrading and thus are suitable for extrusion processing. © 2018 Society of Chemical Industry.

Interactions with 8-Anilinonaphthalene-1-sulfonic Acid (ANS) and Surface Hydrophobicity of Black Gram (Vigna mungo) Phaseolin.

Varying solvent and/or processing conditions can assist to modulate the surface hydrophobicity of functional legume proteins to achieve desired textural properties in the end product.

Measurement of protein digestibility in humans by a dual-tracer method

ABSTRACTBackgroundRecent evaluations of the risk of dietary protein deficiency have indicated that protein digestibility may be a key limiting factor in the provision of indispensable amino acids (IAAs), particularly for vulnerable populations living in challenging environments where intestinal dysfunction may exist. Since the digestion of protein occurs only in the small intestine, and the metabolic activity of colonic bacteria confounds measurements at the fecal level, there is a need to develop noninvasive protein digestibility measurements at the ileal level.ObjectiveWe used a dual-tracer method with stable isotopes to characterize the digestibility of uniformly labeled [13C]-spirulina protein as a standard protein, in comparison to a mixture of 2H-labeled crystalline amino acids, and then demonstrated the use of this standard protein to measure the digestibility of selected legumes (chick pea and mung bean) through the use of proteins that were intrinsically labeled with 2H.DesignThe digestibility of uniformly labeled [13C]-spirulina was first measured in 6 healthy volunteers (3 males and 3 females) by feeding it along with a standard mixture of 2H-labeled amino acids, in a dual-tracer, plateau-fed test meal approach. Next, intrinsically labeled legume protein digestibility was studied with a similar dual-tracer approach, with uniformly labeled [13C]-spirulina as the standard, when processed differently before consumption.ResultsThe average digestibility of IAA in spirulina protein was 85.2%. The average IAA digestibility of intrinsically 2H-labeled chick pea and mung bean protein was 56.6% and 57.7%, respectively. Dehulling of mung bean before ingestion increased the average IAA digestibility by 9.9% in comparison to whole mung bean digestibility.ConclusionsAn innovative, minimally invasive “dual-stable-isotope” method was developed to measure protein digestibility, in which the ingestion of an intrinsically 2H-labeled test protein along with a 13C-labeled standard protein of known digestibility allows for an accurate measure of digestion and absorption of the intrinsically labeled protein. This minimally invasive method is critical to redefining protein quality and will aid in revisiting human protein requirements in different settings and in vulnerable populations. This trial was registered at Clinical Trials Registry—India as CTRI/2017/11/010468.

Bioactive Peptides by in vitro Digestion of Germinated Bean Cotyledons Extrudates

Germinated black bean cotyledons were extruded at two different screw speeds (350 or 400 rpm). Extrudates were digested with pepsin and pancreatin to evaluate the antioxidant and anti-inflammatory activities of hydrolysates collected at 0, 60, 90, 120 and, 180 min. Soluble protein recovered before the enzymatic digestion of extrudates obtained at 350 rpm (E1), or 400 rpm (E2) showed the highest antioxidant (AOX) capacity, with 2,790 or 2,335 µmol eq Trolox/g, respectively and the best nitrogen oxide inhibitory. Even though extrudates presented different peptides profiles, the enzymatic digestion of the storage proteins released similar peptides. RLL and YAL were among the identified peptides obtained after 180 min of enzymatic digestion. Extrusion can be a useful process to produce novel functional ingredients from legume proteins for the food industry.

Effect of germination process on nutrients and phytochemicals contents of faba bean (Vicia faba L.) for weaning food preparation

Faba bean is an important cheap source of legume protein, which can be used as a substitute for animal protein and used to produce weaning food. Two levels of germination duration were applied and ...

Response surface methodology for investigating structure–function relationship of grain legume proteins

Effect of physicochemical properties and secondary structure conformation, on the functional properties of protein concentrates prepared from grain legumes was investigated using response surface methodology. Appropriate models were built on the basis of the best subset technique. Oil-holding capacity was mainly influenced by the secondary structure of proteins, particularly unordered structure, β-sheet, and β-turn. Protein solubility depended on secondary structure and surface hydrophobicity of proteins, and solubility decreased with increasing hydrophobicity. Interaction between solubility and hydrophobicity was significant for emulsifying activity, and EA increased with increasing solubility and hydrophobicity. High emulsion stability of legume proteins necessitated high β-turn secondary structure proportion, solubility, and hydrophobicity. Protein unfolding, particularly high unordered, and β-turn structures and high solubility were required for high foaming ability of legume proteins. In summary, the importance of this study was to increase the utilization of grain legume proteins in the food and non-food industry. Practical applications It is important during food processing or when using an underutilized grain legume protein source as ingredient or supplement in the formulation of food products, to predict the functional properties of the protein. Functional properties are important for the consumer acceptance of food product. The physicochemical properties of protein such as surface hydrophobicity and secondary structure could be used as a basis to predict functionality. In this connection, this study provided effects of the variation of physicochemical properties and secondary structure of grain legume proteins on oil-holding capacity, solubility, emulsifying and foaming properties. The aim of this study was to enhance the utilization of grain legume proteins as nutritional and functional ingredient.

The effects of legume seeds on the lactation performance of dairy cows fed grass silage-based diets

The aim was to study if locally produced organic legume seeds as protein supplement could improve the performance of dairy cows. The experiment was a cyclic change over design were the control diet consisted of grass silage and barley (60:40) on a dry matter (DM) basis. Barley was replaced with rapeseed expeller (RSE), or isonitrogenous supplements of peas, untreated field beans (UFB), heat-treated FB (TFB) or a lower level of TFB (TFB-low) that provided the same dietary metabolizable protein concentrations as of UFB. None of the legume protein supplementations had effect on DM intake (DMI) neither on energy corrected milk yield compared to control. The RSE treatment increased milk (24.8 vs. 23.6 kg d-1) and protein yield (913 vs. 863 g d-1) compared to other protein supplements. Heat-treated FB had no effect on DMI, milk or protein yield compared to UFB. Only RSE resulted in improvements in dairy cows performance in relation to the control diet.

Estimation of extractable protein in botanical fractions of legume and grass species

AbstractWith a globally strong interest in bio‐based products such as fuels and chemicals, a feasible source of protein for the industry with positive economic impacts could be from leaves. However, more knowledge is needed on how to improve the content of extractable protein. Grasses and legumes have a high content of protein with a favourable amino acid composition. The extractable true protein was estimated at two harvest dates in leaf and stem of the legume species white clover (Trifolium repens L.), red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) and the grass species perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea L.) using the Cornell Net Carbohydrate and Protein System. Extractable true protein was more concentrated in the leaf than in the stem of all the species. Easily extractable true protein in the leaf constituted 63%–68% and 54% of crude protein in legumes and grasses respectively. If the cell wall‐bound true protein in the leaf can be extracted, concentration of extractable true protein may increase by 7%–14% and 21%–26% of crude protein in legume and grass respectively. Legume leaf could be superior to grass leaf for protein production in a biorefinery due to higher extractable true protein both on a mass basis and per hectare. In white clover leaf, a significant decline in concentration of extractable true protein with maturity was simultaneous with a substantial increase in extractable true protein per hectare.

Impact of legume protein type and location on lipid oxidation in fish oil-in-water emulsions: Lentil, pea, and faba bean proteins

Emulsion-based delivery systems are being developed to incorporate ω-3 fatty acids into functional foods and beverages. There is interest in formulating these delivery systems from more sustainable and label-friendly ingredients. The aim of this study was therefore to examine the impact of plant-protein emulsifiers on the oxidative stability of 1wt% fish oil-in-water emulsions. Fish oil emulsions stabilized by three types of legume protein (lentil, pea, and faba bean) were produced using a high-pressure microfluidizer. The formation of primary (peroxides) and secondary (TBARS) lipid oxidation products was measured when the emulsions were stored at 37°C under accelerated (+100μM iron sulfate) or non-accelerated (no added iron) conditions for 21 or 33days, respectively. The particle size, charge and microstructure of the emulsions were monitored during storage using light scattering and microscopy to detect changes in physical stability. Emulsions stabilized by whey protein isolate, a commonly used animal-based protein, were utilized as a control. The emulsions formed using whey protein had smaller initial particle sizes, better physical stability, and slightly better stability to lipid oxidation than the ones formed using plant-based proteins. The impact of protein location (adsorbed versus non-adsorbed) on the oxidative stability of the emulsions was also investigated. The presence of non-adsorbed proteins inhibited lipid oxidation, presumably by binding transition metals and reducing their ability to interact with ω-3 fatty acids in the lipid droplets. Overall, these results have important implications for fabricating emulsion-based delivery systems for bioactive lipids, e.g., they indicate that including high levels of non-adsorbed proteins could improve oxidative stability.

Cross-reactivity profiles of legumes and tree nuts using the xMAP® multiplex food allergen detection assay.

The homology between proteins in legumes and tree nuts makes it common for individuals with food allergies to be allergic to multiple legumes and tree nuts. This propensity for allergenic and antigenic cross-reactivity means that commonly employed commercial immunodiagnostic assays (e.g., dipsticks) for the detection of food allergens may not always accurately detect, identify, and quantitate legumes and tree nuts unless additional orthogonal analytical methods or secondary measures of analysis are employed. The xMAP® Multiplex Food Allergen Detection Assay (FADA) was used to determine the cross-reactivity patterns and the utility of multi-antibody antigenic profiling to distinguish between legumes and tree nuts. Pure legumes and tree nuts extracted using buffered detergent displayed a high level of cross-reactivity that decreased upon dilution or by using a buffer (UD buffer) designed to increase the stringency of binding conditions and reduce the occurrence of false positives due to plant-derived lectins. Testing for unexpected food allergens or the screening for multiple food allergens often involves not knowing the identity of the allergen present, its concentration, or the degree of modification during processing. As such, the analytical response measured may represent multiple antigens of varying antigenicity (cross-reactivity). This problem of multiple potential analytes is usually unresolved and the focus becomes the primary analyte, the antigen the antibody was raised against, or quantitative interpretation of the content of the analytical sample problematic. The alternative solution offered here to this problem is the use of an antigenic profile as generated by the xMAP FADA using multiple antibodies (bead sets). By comparing the antigenic profile to standards, the allergen may be identified along with an estimate of the concentration present. Cluster analysis of the xMAP FADA data was also performed and agreed with the known phylogeny of the legumes and tree nuts being analyzed. Graphical abstract The use of cluster analysis to compare the multi-antigen profiles of food allergens.

Crystal structure of Pisum arvense seed lectin (PAL) and characterization of its interaction with carbohydrates by molecular docking and dynamics

The Pisum arvense lectin (PAL), a legume protein belonging to the Vicieae tribe, is capable of specific recognition of mannose, glucose and its derivatives without altering its structure. In this work, the three-dimensional structure of PAL was determined by X-ray crystallography and studied in detail by a combination of molecular docking and molecular dynamics (MD). Crystals belonging to monoclinic space group P21 were grown by the vapor diffusion method at 293 K. The structure was solved at 2.16 Å and was similar to that of other Vicieae lectins. The structure presented Rfactor and Rfree of 17.04% and 22.08%, respectively, with all acceptable geometric parameters. Molecular docking was performed to analyze interactions of the lectin with monosaccharides, disaccharides and high-mannose N-glycans. PAL demonstrated different affinities on carbohydrates, depending on bond orientation and glycosidic linkage present in ligands. Furthermore, the lectin interacted with representative N-glycans in a manner consistent with the biological effects described for Vicieae lectins. Carbohydrate-recognition domain (CRD) in-depth analysis was performed by MD, describing the behavior of CRD residues in complex with ligand, stability, flexibility of the protein over time, CRD volume and topology. This is a first report of its kind for a lectin of the Vicieae tribe.

Rhizobium sp. – a Potential Tool for Improving Protein Content in Peas and Faba Beans

Abstract Legume seed inoculation prior to sowing is a well-known practice in agriculture. Nitrogen fixation, due to the symbiotic relationship between legumes and rhizobia, improves the productivity of legumes. Rhizobia strain specificity can be observed very often, leading to differences in the total protein content. In this study two faba bean cultivars (‘Karmazyn’ and ‘Bartek’) and five pea cultivars (‘Retrija’, ‘Zaiga’, ‘Lāsma’, ‘Vitra’ and ‘Bartek’) were tested using various rhizobia strains. In addition, strain effectivity was observed in four different soil types. Overall, the protein content increase was observed after seed inoculation with Rhizobium sp. Rhizobia strain and plant cultivar interaction specification was observed. Plant cultivar appeared to have a decisive role in the formation of protein content when inoculated with Rhizobium sp. From these pilot experiments, it can be concluded that, when choosing Rhizobium sp. strains for legume inoculation, soil type also should be considered. Rhizobia has the potential to be used as a commercial preparation intended for increasing legume protein content, alongside with increased legume yield; however, different rhizobia strains should be mixed together to achieve the optimal result.

Plant storage proteins - the main nourisching products - from biosynthesis to cellular storage depots.

Storage proteins of legumes are one of the main components of the human and animal diet. The substances collected in their seeds have the pro-health values, supporting the prevention of many civilization diseases. However, there are still many uncertainties about the mechanisms leading to the production of nutritious seeds. It is also difficult to identify which of their constituents and in what final form are responsible for the observed protective effects in vivo. In this work, on the background of different types of storage proteins, these deposited mainly in legumes were in the focus of interest. They were characterized on the example of pea (Pisum sativum) proteins. Mechanisms associated with their biosynthesis and transport to specific cellular compartments was presented. Ways of their post-translational processing, segregation and storage in the specific vacuoles were also discussed. Therefore, the paper presents the state-of-the-art knowledge concerning the processes making the accumulated protein deposits ready to use by plants, animals and humans.

Impact of organic practices on growth, yield, and greenhouse gas emissions by pea landraces

Legume crops constitute an essential component of rotations in organic farming systems due to their ability to provide plant available nitrogen to agricultural ecosystems arising from symbiotic N2 fixation. However, there is a general need to increase grain legume protein production in Europe so as to meet the increasing demand while reducing resource utilization, thereby contributing to mitigation of global climate change. Taking this need into consideration, a field-based experiment with pea (Pisum sativum L.) was carried out in a field certified for organic agriculture from November 2014 to June 2015. The experiment was laid out in a split-plot design with two main treatments (conventional and organic farming system) and four sub-plots per main plot corresponding to four different pea genotypes, particularly one commercial cultivar ('Onward'), and three local landraces ('Amorgos', 'Andros' and 'Schinousa'). Standard inorganic fertilizer (11-15-15, N:P2O5:K2O) and sheep manure were used as base dressings in the conventional and the organically-treated plots, respectively. The aim of the experiment was to test the performance of each pea genotype in organic farming crops as compared to conventional cropping, in terms of: green seed yield, and greenhouse gas (GHG) emissions. The results of this study indicate that 'Andros' increased significantly the above-ground biomass and the fresh green seed production on the harvesting date when compared with all the other genotypes. In addition, there were significant differences in cumulative N2O fluxes between the pea cultivars with 'Schinousa' producing the highest N2O amounts and 'Andros' the lowest. In conclusion, the pea genotype seems to have a strong influence on both GHG emissions and production and therefore, appropriate selection of cultivars is imperative for efficient use of this legume in organic cropping systems.

Functional Properties and Oxidative Stability of Flaxseed Oil Microencapsulated by Spray Drying Using Legume Proteins in Combination with Soluble Fiber or Trehalose

The objective of this study was to evaluate the potential of double wall material combinations, using legume protein (soy protein isolate and pea protein isolate) in combination with wheat dextrin soluble fiber or trehalose, as alternative materials for microencapsulation of flaxseed oil by spray drying. The obtained preparations, with oil content of 35%, were fine and difficult flowing powders, regardless of their composition. The 1% addition of silica to the powders significantly reduced their cohesiveness and improved their flowability. The efficiency of microencapsulation, calculated based on oil fat content, ranged from 62 to 98% and was higher in the powders with trehalose and in the powders containing soy protein. Effective protection against oxidation of microencapsulated oil was achieved in the protein-trehalose matrix, especially in the case of the vacuum-packed powders with pea protein during storage at refrigeration temperature. Replacing trehalose with soluble fiber enabled formation of powders less susceptible to caking under conditions of increased humidity, but it resulted in decreased microencapsulation efficiency. The combination of pea protein/carbohydrate resulted in the formation of microcapsules with porous structure, especially in the system with soluble fiber. With time, the structure of the primary emulsions and those reconstituted from powders containing pea protein changed from liquid to greasy and paste-like.

Comparative Evaluation of Antimicrobial Activity and Functional Properties of Native and Esterified Legume Proteins

Comparative Evaluation of Antimicrobial Activity and Functional Properties of Native and Esterified Legume Proteins

Physicochemical, rheological, bioactive and consumer acceptance analyses of concha-type Mexican sweet bread containing Lima bean or cowpea hydrolysates

Foods may be fortified to improve their nutritional value and bio-functional properties. Protein sources are used to improve physicochemical properties in foods, and hydrolyzed legume proteins are a promising alternative. A Lima bean (Phaseolus lunatus) protein concentrate was hydrolyzed using pepsin, and a cowpea (Vigna unguiculata) concentrate was hydrolyzed using a pepsin-pancreatin sequential system. The Lima bean hydrolysate had a degree of hydrolysis of 17.38%, and the cowpea one of 30.75%. When were added at 1 or 3% to dough for making concha-type Mexican sweet bread, dough tenacity and extensibility increased at the higher inclusion level. Physicochemical, bioactivity (ACE inhibition and antioxidant activity) and consumer acceptance analyses of the breads were performed. Protein content was higher in the bread containing hydrolysates. The control treatment had the lowest ACE inhibitory activity and TEAC value. At both inclusion levels, ACE inhibitory activity was higher in the breads containing Lima bean hydrolysates than those containing cowpea hydrolysates. This activity increased with inclusion level in both hydrolysate treatments. Bread containing the cowpea hydrolysate exhibited an acceptance level (p > 0.05) equal to that of the control treatment. Addition of legume hydrolysates is a promising way of improving bread nutritional and biological values without affecting sensory parameters.

Grain protein estimation and SDS-PAGE profilingof six important arid legumes

Grain protein content and protein profiles of six arid grain legumes belonging to three different tribes were studied. Average grain protein (per cent) of horse gram, cowpea, moth bean, guar, chickpea and green gram was 20.29, 22.8, 22.6, 20.6, 21.82, and 20.40 respectively. All the six arid legumes were clearly differentiated based on the protein banding patterns generated through SDS-PAGE. The molecular weight range of proteins in different legumes was observed to be ~16 to ~250kD. Interestingly, in chickpea, moth bean and horse gram proteins &gt;100kD were not mostly observed. Further, distinct proteins were observed indicating inter-varietal differences in horse gram (CRHG-19), cowpea (RC-101) and guar (HG-2-20), which could be useful in varietal identification. The different legumes were broadly clustered in to four clusters. Further, chickpea (Cicereae), green gram and cowpea (Phaseoleae) were clustered together. The similarity indexes of varieties and individual crops ranged from 0.667 to 0.950 and 0.425 to 0.821 respectively. Though the six legumes belong to Leguminosae they have distinct protein profiles which could be useful in species/varietal identification.