Structural aspects of legume proteins and nutraceutical properties

Short-term germinated legume flours as functional ingredients in food products

Unlocking the potential of legumes through short-term germination offers an innovative approach to improving the functionality of the resultant flour. This review examines the multifaceted benefits of short-term germinated legume flour, emphasizing the enzymatic activities that breakdown complex legume compounds into simpler forms and reduce anti-nutritional factors. This process improves digestibility, nutrient bioavailability, and health-promoting properties. Furthermore, short-term germination enhances the techno-functional properties of legume flours without compromising their quality, avoiding excessive starch and protein degradation associated with prolonged germination. This review also explores the applications of short-term germinated legume flours in developing nutritious and healthy food products tailored to diverse dietary needs. Subsequent integration of these short-term germinated flours into food products provides a route for the development of cost-effective, nutritious, and sustainable options that can address malnutrition and enhance overall well-being.

Synergistic effects of superfine grinding and high hydrostatic pressure on the contents, distribution, digestive behaviors and antioxidant activities of polyphenols in barley leaves

Barley leaves (BLs) naturally contained abundant phenolics, most of which are hardly completely released from food matrix during gastrointestinal digestion. Superfine grinding (SFG) and high hydrostatic pressure (HHP) are generally used to treat the functional plants due to their effectiveness to cell wall-breaking and improvement of nutraceutical bioavailability. Thus, this study investigated the synergistic effects of SFG and HHP (100, 300, 500 MPa/20 min) on the bioaccessbility of typical phenolics in BLs during the simulated in-vitro digestion. The results demonstrated that the highest bioaccessbility (40.98%) was found in the ultrafine sample with HHP at 500 MPa. CLSM and SEM confirmed SFG led to microstructurally rapture of BLs. Moreover, the recovery index of ABTS radical scavenging activity and FRAP of HHP-treated ultrafine and fine BLs samples maximumly increased by 53.62% and 9.61%, respectively. This study is expecting to provide the theoretical basis to improve the consumer acceptance of BLs.

The role of fiber in modulating plant protein-induced metabolic responses

The rising consumption of plant protein foods and the emergence of meat alternatives have prompted interest in the health benefits of such products, which contain fiber in addition to protein. This review investigates the effect of fiber on plant-based protein metabolism and evaluates its contribution to gut-derived health impacts. Plant proteins, which often come with added fiber, can have varying health outcomes. Factors such as processing and the presence of fiber and starch influence the digestibility of plant proteins, potentially leading to increased proteolytic fermentation in the gut and the production of harmful metabolites. However, fermentable fiber can counteract this effect by serving as a primary substrate for gut microbes, decreasing proteolytic activity. The increased amount of fiber, rather than the protein source itself, plays a significant role in the observed health benefits of plant-based diets in human studies. Differences between extrinsic and intrinsic fiber in the food matrix further impact protein fermentation and digestibility. Thus, in novel protein products without naturally occurring fiber, the health impact may differ from conventional plant protein sources. The influence of various fibers on plant-based protein metabolism throughout the gastrointestinal tract is not fully understood, necessitating further research.

Fluorescent carbon dot embedded polystyrene: an alternative for micro/nanoplastic translocation study in leguminous plants

Micro/nanoplastics are widespread in terrestrial ecosystem. Even though many studies have been reported on the effects of these in marine environment, studies concerning their accumulation and impact on terrestrial ecosystem have been scanty. The current study was designed to determine how terrestrial plants, especially legumes, interact with micro/nanoplastics to gain insights into their uptake and translocation. The paper describes the synthesis of fluorescent carbon dot embedded polystyrene (CDPS) followed by its characterization. Translocation studies at different concentrations from 2 to 100% (v/v) for tracking the movement and accumulation of microplastics in Vigna radiata and Vigna angularis were performed. The optical properties of the synthesized CDPS were investigated, and their translocation within the plants was visualized using fluorescence microscopy. These findings were further validated by scanning electron microscopy (SEM) imaging of the plant sections. The results showed that concentrations higher than 6% (v/v) displayed noticeable fluorescence in the vascular region and on the cell walls, while concentrations below this threshold did not. The study highlights the potential of utilizing fluorescent CDPS as markers for investigating the ecological consequences and biological absorption of microplastics in agricultural systems. This method offers a unique technique for monitoring and analyzing the routes of microplastic accumulation in edible plants, with significant implications for both food safety and environmental health.

Encapsulation of Lactobacillus plantarum in W1/O/W2 double emulsions stabilized with the high-intensity ultrasound-treated pea protein and pectin

This study focuses on developing a water-in-oil-in-water (W1/O/W2) double emulsion system using high-intensity ultrasound (HIU)-treated pea protein isolate (HIU-PPI) and pectin to encapsulate Lactobacillus plantarum (L. plantarum). The effects of ultrasound treatment on pea protein isolate (PPI) characteristics such as solubility, particle size, emulsification, surface hydrophobicity, and surface free sulfhydryl group were examined, determining optimal HIU processing conditions was 400 W for 10 min. The developed W1/O/W2 double emulsion system based on HIU-PPI demonstrated effective encapsulation and protection of L. plantarum, especially at the HIU-PPI concentration of 4 %, achieving an encapsulation efficiency of 52.65 %. Incorporating both HIU-PPI and pectin as emulsifiers increased the particle size and significantly enhanced the emulsion's viscosity. The highest bacterial encapsulation efficiency of the emulsion, 59.94 %, was attained at a HIU to pectin concentration ratio of 3:1. These emulsions effectively encapsulate and protect L. plantarum, with the concentration of HIU-PPI being a critical factor in enhancing probiotic survival under simulated gastrointestinal digestion. However, the concurrent utilization of pectin and HIU-PPI as emulsifiers did not provide a notable advantage compared to the exclusive use of HIU-PPI in enhancing probiotic viability during in vitro simulated digestion. This research offers valuable perspectives for the food industry on harnessing environmentally friendly, plant-based proteins as emulsifiers in probiotic delivery systems. It underscores the potential of HIU-modified pea protein and pectin in developing functional food products that promote the health benefits of probiotics.

Effects of inulin with different polymerization degrees on the structural and gelation properties of potato protein

This study investigated the effect of inulin with different polymerization degrees (DP), including L-inulin (DP 2-6), M-inulin (DP 10-23) and H-inulin (DP 23-46), on the structural and gelation properties of potato protein isolate (PPI). Results revealed that textural properties (hardness, cohesiveness, springiness and chewiness) and water-holding capacity (WHC) of PPI-inulin composite gels were positively correlated with the inulin DP and addition content at 0-1.5% (w/v), but deteriorated at 2% due to phase separation. The addition of 1.5% H-inulin showed the most significant increment effects on the WHC (18.65%) and hardness (2.84 N) of PPI gel. Furthermore, M-/H-inulin were more effective in increasing the whiteness and surface hydrophobicity, as well as in strengthening hydrogen bonds and hydrophobic interactions than L-inulin. Fourier transform infrared spectroscopy analysis and microstructural observation indicated that inulin with higher DP promoted more generation of β-sheet structures, and leading to the formation of stronger and finer network structures.

Application of legumes in plant-based milk alternatives: a review of limitations and solutions

In recent years, a global shift has been observed toward reducing the consumption of animal-derived foods in favor of healthier and more sustainable dietary choices. This has led to a steady growth in the market for plant-based milk alternatives (PBMAs). Projections suggest that this market will reach a value of USD 69.8 billion by 2030. Legumes, being traditional and nutritious ingredients for PMBAs, are rich in proteins, dietary fibers, and other nutrients, with potential health benefits such as anticancer and cardiovascular disease prevention. In this review, the application of 12 legumes in plant-based milk alternatives was thoroughly discussed for the first time. However, compared to milk, processing of legume-based beverages can lead to deficiencies such as nutritional imbalance, off-flavor, and emulsion stratification. Considering the potential and challenges associated with legume-based beverages, this review aims to provide a scientific comparison between legume-based beverages and cow's milk in terms of nutritional quality, organoleptic attributes and stability, and to summarize ways to improve the deficiencies of legume-based beverages in terms of raw materials and processing method improvements. In conclusion, the legume-based beverage industry will be better enhanced and developed by improving the issues.

Effects of calcium chloride on the gelling and digestive characteristics of myofibrillar protein in Litopenaeus vannamei

In this study, the effects of CaCl2 (0, 25, 50, 75, and 100 mM) on the gelling and digestive properties of the myofibrillar protein (MP) in Litopenaeus vannamei were investigated. The results showed that increasing CaCl2 concentration led to changes in the tertiary structure of MP. Specifically, compared with the control group, a 64.31 % increase in surface hydrophobicity and a 45.90 % decrease in the sulfhydryl group were observed after 100 mM CaCl2 treatment. Correspondingly, the water holding capacity and strength of the MP gel increased by 24.46 % and 55.99 %, respectively. These changes were positively correlated with the rheological properties, microstructure pore size, and content of non-flowable water. The mechanical properties of MP gel were improved, and the microstructure became more compact with the increase in CaCl2 concentration. Furthermore, the particle size of the digested MP gels decreased in the presence of CaCl2, which improved the digestion characteristics of MP gels.

Ultra-high pressure improved gelation and digestive properties of Tai Lake whitebait myofibrillar protein

This study investigated the effects of ultra-high pressure (UHP) at different levels on the physicochemical properties, gelling properties, and in vitro digestion characteristics of myofibrillar protein (MP) in Tai Lake whitebait. The α-helix gradually unfolded and transformed into β-sheet as the pressure increased from 0 to 400 MPa. In addition, the elastic modulus (G') and viscous modulus (G'') of the 400 MPa-treated MP samples increased by 4.8 and 3.8 times, respectively, compared with the control group. The gel properties of the MP also increased significantly after UHP treatment, e.g., the gel strength increased by a 4.8-fold when the pressure reached 400 Mpa, compared with the control group. The results of in vitro simulated digestion showed that the 400 MPa-treated MP gel samples showed a 1.8-fold increase in digestibility and a 69.6 % decrease in digestible particle size compared with the control group.

Tailoring the Techno-Functional Properties of Fava Bean Protein Isolates: A Comparative Evaluation of Ultrasonication and Pulsed Electric Field Treatments

The fava bean protein isolate (FBPI) holds promise as a sustainable plant-based protein ingredient. However, native FBPIs exhibit limited functionality, including unsuitable emulsifying activities and a low solubility at a neutral pH, restricting their applications. This study is focused on the effect of ultrasonication (US) and pulsed electric fields (PEF) on modulating the techno-functional properties of FBPIs. Native FBPIs were treated with US at amplitudes of 60-90% for 30 min in 0.5 s on-and-off cycles and with PEF at an electric field intensity of 1.5 kV/cm with 1000-4000 pulses of 20 μs pulse widths. US caused a reduction in the size and charge of the FBPIs more prominently than the PEF. Protein characterization by means of SDS-PAGE illustrated that US and PEF caused severe-to-moderate changes in the molecular weight of the FBPIs. In addition, a spectroscopic analysis using Fourier-transform infrared (FTIR) and circular dichroism (CD) revealed that US and the PEF induced conformational changes through partial unfolding and secondary structure remodeling from an α-helix to a β-sheet. Crystallographic and calorimetric determinations indicated decreased crystallinity and lowered thermal transition temperatures of the US- and PEF-modified FBPIs. Overall, non-thermal processing provided an effective strategy for upgrading FBPIs' functionality, with implications for developing competitive plant-based protein alternatives.

Overview of the Incorporation of Legumes into New Food Options: An Approach on Versatility, Nutritional, Technological, and Sensory Quality

Consumers are more aware and demanding of healthy food options, besides being concerned with environment-friendly consumption. This paper aims to evaluate nutritional, technological, and sensory characteristics of legumes and their products' quality and versatility, considering potential applications in new food options. Legumes are foods that have a recognized nutritional group since they have high protein and fiber content. However, their consumption is still somehow limited for some reasons: in some countries it is not easy to find all the species or cultivars, they need an organization and planning before preparation since they need soaking, and there is the presence of antinutritional factors. Due to the different functionalities of legume proteins, they can be applied to a variety of foods and for different purposes, as grains themselves, aquafaba, extracts, flours, brans, and textured proteins and sprouts. These products have been inserted as ingredients in infant food formulations, gluten-free foods, vegetarian diets, and in hybrid products to reduce food costs as well. Foods such as bread, cakes, cookies, meat analogues, and other baked or cooked products have been elaborated with nutritional, technological and sensory quality. Further development of formulations focused on improving the quality of legume-based products is necessary because of their potential and protein quality.

Common beans as a source of food ingredients: Techno-functional and biological potential

Common beans are an inexpensive source of high-quality food ingredients. They are rich in proteins, slowly digestible starch, fiber, phenolic compounds, and other bioactive molecules that could be separated and processed to obtain value-added ingredients with techno-functional and biological potential. The use of common beans in the food industry is a promising alternative to add nutritional and functional ingredients with a low impact on overall consumer acceptance. Researchers are evaluating traditional and novel technologies to develop functionally enhanced common bean ingredients, such as flours, proteins, starch powders, and phenolic extracts that could be introduced as functional ingredient alternatives in the food industry. This review compiles recent information on processing, techno-functional properties, food applications, and the biological potential of common bean ingredients. The evidence shows that incorporating an adequate proportion of common bean ingredients into regular foods such as pasta, bread, or nutritional bars improves their fiber, protein, phenolic compounds, and glycemic index profile without considerably affecting their organoleptic properties. Additionally, common bean consumption has shown health benefits in the gut microbiome, weight control, and the reduction of the risk of developing noncommunicable diseases. However, food matrix interaction studies and comprehensive clinical trials are needed to develop common bean ingredient applications and validate the health benefits over time.

Functional Bioactivities of Soluble Seed Proteins from Two Leguminous Seeds

Storage proteins from Sphenostylis stenocarpa and Phaseolus lunatus were fractionated, and their in vitro bioactivities were investigated. Albumin, globulin, prolamin, and glutelin constituents of the respective seeds were successively fractionated using the modified Osborne method. Phenylmethylsulfonyl fluoride (1 mM) was used as a protease inhibitor. The antioxidant, anti-inflammatory, and acetylcholinesterase-inhibitory activities of the protein fractions were evaluated using different appropriate techniques. Globulin was the predominant fraction, with a yield of 43.21±0.01% and 48.19±0.03% for S. stenocarpa and P. lunatus, respectively, whereas prolamin was not detected in both seeds. The protein fraction markedly scavenges hydroxyl radicals, nitric oxide radicals, and 2,2-diphenyl-1-picryldydrazyl radicals with concomitant high free radical-reducing power. Albumin and globulin fractions elicited the highest acetylcholinesterase-inhibitory potential of 48.75% and 49.75%, respectively, indicating their great application potential in managing neurodegenerative diseases. In this study, the albumin, globulin, and glutelin fractions of these underutilized legumes showed great analeptic bioactivities, which could be utilized as health-promoting dietary supplements/products.

Effects of ultrasonic treatment on the structural and functional properties of cactus (Opuntia ficus-indica) seed protein

With the steady increase in the consumption of ultra-processed foods, there is growing interest in sustainable diets that include more plant protein. However, little information is available regarding the structural and functional properties of cactus (Opuntia ficus-indica) seed protein (CSP), a by-product of the cactus seed food-processing chain. This study aimed to explore the composition and nutritional value of CSP and reveal the effects of ultrasound treatment on protein quality. Protein chemical structure analysis showed that an appropriate intensity of ultrasound treatment (450 W) could significantly increase protein solubility (96.46 ± 2.07%) and surface hydrophobicity (13.76 ± 0.85 μg), decrease the content of T-SH (50.25 ± 0.79 μmol/g) and free-SH (8.60 ± 0.30 μmol/g), and enhance emulsification characteristics. Circular dichroism analysis further confirmed that the ultrasonic treatment increased the α-helix and random coil content. Amino acid analysis also suggested that ultrasound treatment (450 W) increased the hydrophobic amino acid content. To evaluate the impact of changes in the chemical structure, its digestion behavior was studied. The results showed that ultrasound treatment increased the release rate of free amino acids. Furthermore, nutritional analysis showed that the digestive products of CSP by ultrasound treatment can significantly enhance the intestinal permeability, increase the expression of ZO-1, Occludin and Claudin-1, thus repairing LPS induced intestinal barrier disfunction. Hence, CSP is a functional protein with high value, and ultrasound treatment is recommended. These findings provide new insights into the comprehensive utilization of cactus fruits.

Relationship between Protein Digestibility and the Proteolysis of Legume Proteins during Seed Germination

Legume seed protein is an important source of nutrition, but generally it is less digestible than animal protein. Poor protein digestibility in legume seeds and seedlings may partly reflect defenses against herbivores. Protein changes during germination typically increase proteolysis and digestibility, by lowering the levels of anti-nutrient protease inhibitors, activating proteases, and breaking down storage proteins (including allergens). Germinating legume sprouts also show striking increases in free amino acids (especially asparagine), but their roles in host defense or other processes are not known. While the net effect of germination is generally to increase the digestibility of legume seed proteins, the extent of improvement in digestibility is species- and strain-dependent. Further research is needed to highlight which changes contribute most to improved digestibility of sprouted seeds. Such knowledge could guide the selection of varieties that are more digestible and also guide the development of food preparations that are more digestible, potentially combining germination with other factors altering digestibility, such as heating and fermentation. Techniques to characterize the shifts in protein make-up, activity and degradation during germination need to draw on traditional analytical approaches, complemented by proteomic and peptidomic analysis of mass spectrometry-identified peptide breakdown products.

Vegetable proteins as encapsulating agents: Recent updates and future perspectives

The use of proteinaceous material is desired as it forms a protective gelation around the active core, making it safe through temperature, pH, and O2 in the stomach and intestinal environment. During the boom of functional food utilization in this era of advancement in drug delivery systems, there is a dire need to find more protein sources that could be explored for the potential of being used as encapsulation materials, especially vegetable proteins. This review covers certain examples which need to be explored to form an encapsulation coating material, including soybeans (conglycinin and glycinin), peas (vicilin and convicilin), sunflower (helianthins and albumins), legumes (glutenins and albumins), and proteins from oats, rice, and wheat. This review covers recent interventions exploring the mentioned vegetable protein encapsulation and imminent projections in the shifting paradigm from conventional process to environmentally friendly green process technologies and the sensitivity of methods used for encapsulation. Vegetable proteins are easily biodegradable and so are the procedures of spray drying and coacervation, which have been discussed to prepare the desired encapsulated functional food. Coacervation processes are yet more promising in the case of particle size formation ranging from nano to several hundred microns. The present review emphasizes the significance of using vegetable proteins as capsule material, as well as the specificity of encapsulation methods in relation to vegetable protein sensitivity and the purpose of encapsulation accompanying recent interventions.

Alternations in the multilevel structures of chickpea protein during fermentation and their relationship with digestibility

This study investigated the effects of fermentation on in vitro protein digestibility of chickpeas and their relationship with the variations of multilevel structures of chickpea protein. The results showed that lactobacillus fermentation not only increased the solubility of chickpea protein but also enhanced the hydrolysis of protein during gastric and intestinal digestion by altering the multilevel structures of chickpea protein. The degree of hydrolysis, free amino acid content, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that macromolecule chickpea protein was hydrolyzed during fermentation. Raman and UV spectroscopy scans indicated that the α-helix content increased while the content of β-sheet in chickpea protein dropped significantly after fermentation. As for fermented chickpea protein, the aromatic acid residues were gradually more exposed than the unfermented chickpea protein, and the intramolecular disulfide bond was generally converted to the intermolecular form. Our findings showed that fermentation changed the multilevel structures of chickpea protein, degrading spherical structures into looser states that were more responsible for their effective hydrolysis during digestion. Furthermore, better digestibility of chickpea protein would stimulate the use of chickpea fermentation in food products.

Prediction and Evaluation of Bioactive Properties of Cowpea Protein Hydrolysates

Cowpea protein hydrolysates were prepared using thermolysin, alcalase, and trypsin and analysed for bioactive properties, and then, the release of bioactive peptides was investigated in silico. It was found that the degree of hydrolysis reached 48% after 24 h hydrolysis with alcalase. The hydrolysate prepared using alcalase showed higher ACE inhibitory (62%) and DPPH scavenging activity (19%). SDS-PAGE analysis revealed that vignin was the major protein in cowpea protein isolate. In silico analysis indicated the presence of potential bioactive peptides with potent bioactivity in the primary structure of proteins. The 3D structure of proteins was built, upon which bioactive peptides were mapped using their location in the primary structure. The secondary structure and solvent accessible surface around each bioactive peptide were then calculated. On this basis, the higher degree of hydrolysis and bioactive properties of cowpea protein hydrolysate prepared by alcalase were explained, and structural factors influencing the release of bioactive peptides were investigated.

Size exclusion chromatography to evaluate in vitro proteolysis: a case study on the impact of microstructure in pulse powders

Cellular pulse ingredients are increasingly being studied but little knowledge on their proteolysis patterns upon digestion is available. This study investigated a size exclusion chromatography (SEC) approach to study in vitro protein digestion in chickpea and lentil powders, providing novel insights into proteolysis kinetics and the evolution of molecular weight distributions in the (solubilized) supernatant and (non-solubilized) pellet fractions. For the quantification of proteolysis, SEC-based analysis was compared to the commonly used OPA (o-phthaldialdehyde) approach and nitrogen solubilized upon digestion, leading to highly correlated proteolysis kinetics. Generally, all approaches confirmed that microstructure dictated proteolysis kinetics. However, SEC analysis delivered an additional level of molecular insight. For the first time, SEC revealed that while bioaccessible fractions reached a plateau in the small intestinal phase (around 45-60 min), proteolysis continued in the pellet, forming smaller but mostly insoluble peptides. SEC elutograms showed pulse-specific proteolysis patterns, unidentified using other current state-of-the-art methods.

Characterisation of Bioactive Peptides from Red Alga Gracilariopsis chorda

In this study, we studied the bioactive peptides produced by thermolysin hydrolysis of a water-soluble protein (WSP) from the red alga Gracilariopsis chorda, whose major components are phycobiliproteins and Ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCo). The results showed that WSP hydrolysate exhibited significantly higher ACE inhibitory activity (92% inhibition) compared to DPP-IV inhibitory activity and DPPH scavenging activity. The phycobiliproteins and RuBisCo of G. chorda contain a high proportion of hydrophobic (31.0-46.5%) and aromatic (5.1-46.5%) amino acid residues, which was considered suitable for the formation of peptides with strong ACE inhibitory activity. Therefore, we searched for peptides with strong ACE inhibitory activity and identified two novel peptides (IDHY and LVVER). Then, their interaction with human ACE was evaluated by molecular docking, and IDHY was found to be a promising inhibitor. In silico analysis was then performed on the structural factors affecting ACE inhibitory peptide release, using the predicted 3D structures of phycobiliproteins and RuBisCo. The results showed that most of the ACE inhibitory peptides are located in the highly solvent accessible α-helix. Therefore, it was suggested that G. chorda is a good source of bioactive peptides, especially ACE-inhibitory peptides.

Nutritional, functional, and bioactive properties of african underutilized legumes

Globally, legumes are vital constituents of diet and perform critical roles in maintaining well-being owing to the dense nutritional contents and functional properties of their seeds. While much emphasis has been placed on the major grain legumes over the years, the neglected and underutilized legumes (NULs) are gaining significant recognition as probable crops to alleviate malnutrition and give a boost to food security in Africa. Consumption of these underutilized legumes has been associated with several health-promoting benefits and can be utilized as functional foods due to their rich dietary fibers, vitamins, polyunsaturated fatty acids (PUFAs), proteins/essential amino acids, micro-nutrients, and bioactive compounds. Despite the plethora of nutritional benefits, the underutilized legumes have not received much research attention compared to common mainstream grain legumes, thus hindering their adoption and utilization. Consequently, research efforts geared toward improvement, utilization, and incorporation into mainstream agriculture in Africa are more convincing than ever. This work reviews some selected NULs of Africa (Adzuki beans (Vigna angularis), African yam bean (Sphenostylis stenocarpa), Bambara groundnut (Vigna subterranea), Jack bean (Canavalia ensiformis), Kidney bean (Phaseolus vulgaris), Lima bean (Phaseolus lunatus), Marama bean (Tylosema esculentum), Mung bean, (Vigna radiata), Rice bean (Vigna Umbellata), and Winged bean (Psophocarpus tetragonolobus)), and their nutritional, and functional properties. Furthermore, we highlight the prospects and current challenges associated with the utilization of the NULs and discusses the strategies to facilitate their exploitation as not only sources of vital nutrients, but also their integration for the development of cheap and accessible functional foods.

Starch-protein interaction effects on lipid metabolism and gut microbes in host

The purpose of this experiment was to investigate the effects of different starch and protein levels on lipid metabolism and gut microbes in mice of different genders. A total of 160 male mice were randomly assigned to sixteen groups and fed a 4 × 4 Latin square design with dietary protein concentrations of 16, 18, 20, and 22%, and starch concentrations of 50, 52, 54, and 56%, respectively. The results of the study showed that different proportions of starch and protein had obvious effects on the liver index of mice, and there was a significant interaction between starch and protein on the liver index (p = 0.005). Compared with other protein ratio diets, 18% protein diet significantly increased the serum TBA concentration of mice (p < 0.001), and different starch ratio diets had no effect on serum TBA concentration (p = 0.442). It was proved from the results of ileal tissue HE staining that the low protein diet and the low starch diet were more favorable. There was a significant interaction between diets with different starch and protein levels on Bacteroidetes, Firmicutes and Proteobacteria abundance in feces of mice (p < 0.001). Compared with 16 and 18% protein ratio diets, both 20 and 22% protein diets significantly decreased the Parabacteroides and Alistipes abundance in feces of mice (p < 0.05), and 52% starch ratio diet significantly decreased the Parabacteroides and Alistipes abundance than 50% starch ratio diet of mice (p < 0.05). There was a significant interaction between diets with different starch and protein levels on Parabacteroides (p = 0.014) and Alistipes (p = 0.001) abundance in feces of mice. Taken together, our results suggest that a low protein and starch diet can alter lipid metabolism and gut microbes in mice.

Escalate protein plates from legumes for sustainable human nutrition

Protein is one of the most important, foremost, and versatile nutrients in food. The quantity and quality of protein are determinants of its nutritional values. Therefore, adequate consumption of high-quality protein is essential for optimal growth, development, and health of humans. Based on short-term nitrogen balance studies, the Recommended Dietary Allowance of protein for the healthy adult with minimal physical activity is 0.8 g protein/kg body weight (BW) per day. Proteins are present in good quantities in not only animals but also in plants, especially in legumes. With the growing demand for protein, interest in plant proteins is also rising due to their comparative low cost as well as the increase in consumers' demand originating from health and environmental concerns. Legumes are nutrient-dense foods, comprising components identified as "antinutritional factors" that can reduce the bioavailability of macro and micronutrients. Other than nutritive value, the physiochemical and behavioral properties of proteins during processing plays a significant role in determining the end quality of food. The term "complete protein" refers to when all nine essential amino acids are present in the correct proportion in our bodies. To have a balanced diet, the right percentage of protein is required for our body. The consumption of these high protein-containing foods will lead to protein sustainability and eradicate malnutrition. Here, we shed light on major opportunities to strengthen the contribution of diversity in legume crops products to sustainable diets. This review will boost awareness and knowledge on underutilized proteinous foods into national nutritional security programs.

Comparison on Protein Bioaccessibility of Soymilk Gels Induced by Glucono-δ-Lactone and Lactic Acid Bacteria

In this study, the protein bioaccessibility of soymilk gels produced by the addition of glu-cono-δ-lactone (GDL) and fermentation with lactic acid bacteria (LAB) was examined using an in vitro gastrointestinal simulated digestion model. The in vitro protein digestibility, soluble protein content, free amino acids contents, degree of hydrolysis, electrophoretic patterns, and peptide content were measured. The results suggested that acid-induced soymilk gel generated by GDL (SG) showed considerably reduced in vitro protein digestibility of 75.33 ± 1.00% compared to the soymilk gel induced by LAB (SL) of 80.57 ± 1.53% (p < 0.05). During the gastric digestion stage, dramatically higher (p < 0.05) soluble protein contents were observed in the SG (4.79−5.05 mg/mL) than that of SL (4.31−4.35 mg/mL). However, during the later intestinal digestion phase, the results were the opposite. At the end of the gastrointestinal digestion phase, the content of small peptides was not significantly different (p > 0.05) between the SL (2.15 ± 0.03 mg/mL) and SG (2.17 ± 0.01 mg/mL), but SL showed higher content of free amino acids (20.637 g/L) than that of SG (19.851 g/L). In general, soymilk gel induced by LAB had a higher protein bioaccessibility than the soymilk gel coagulated by GDL.

Resistant Protein: Forms and Functions

Several global health risks are related to our dietary lifestyle. As a consequence of the overconsumption of ultra-processed and highly digestible protein (150-200% of the recommended value), excess dietary proteins reach the colon, are hydrolysed to peptides and amino acids by bacterial proteases and fermented to various potentially toxic end products. A diet reformulation strategy with reduced protein content in food products appears to be the most effective approach. A potential approach to this challenge is to reduce food digestibility by introducing resistant protein into the diet that could positively influence human health and gut microbiome functionality. Resistant protein is a dietary constituent not hydrolysed by digestive enzymes or absorbed in the human small intestine. The chemical conformation and the amino acid composition strictly influence its structural stability and resistance to in vivo proteolysis and denaturation. Responding to the important gap in our knowledge regarding the digestibility performance of alternative proteins, we hypothesise that resistant proteins can beneficially alter food functionality via their role in improving metabolic properties and health benefits in human nutrition, similar to fibres and resistant starches. A multidisciplinary investigation of resistant protein will generate tremendous scientific impact for other interlinked societal, economic, technological and health and wellbeing aspects of human life.

The Current Situation of Pea Protein and Its Application in the Food Industry

Pea (Pisum sativum) is an important source of nutritional components and is rich in protein, starch, and fiber. Pea protein is considered a high-quality protein and a functional ingredient in the global industry due to its low allergenicity, high protein content, availability, affordability, and deriving from a sustainable crop. Moreover, pea protein has excellent functional properties such as solubility, water, and oil holding capacity, emulsion ability, gelation, and viscosity. Therefore, these functional properties make pea protein a promising ingredient in the food industry. Furthermore, several extraction techniques are used to obtain pea protein isolate and concentrate, including dry fractionation, wet fractionation, salt extraction, and mild fractionation methods. Dry fractionation is chemical-free, has no loss of native functionality, no water use, and is cost-effective, but the protein purity is comparatively low compared to wet extraction. Pea protein can be used as a food emulsifier, encapsulating material, a biodegradable natural polymer, and also in cereals, bakery, dairy, and meat products. Therefore, in this review, we detail the key properties related to extraction techniques, chemistry, and structure, functional properties, and modification techniques, along with their suitable application and health attributes.

Modeling the Thermal Denaturation of the Protein-Water System in Pulses (Lentils, Beans, and Chickpeas)

Thermal treatment applied during the cooking of pulses leads to denaturation and even aggregation of the proteins, which may impact protein digestibility. Thermal transitions of lentil, chickpea, and bean proteins were studied using differential scanning calorimetry (DSC). Protein-enriched samples were obtained by dry air classification of dehulled seeds and were heated to 160 °C, with water contents ranging from 0.2 to 4 kg/kg on a dry basis. The DSC peaks of the resulting endotherms were successfully modeled as overlapping Gaussian functions. The denaturation temperatures were modeled as a function of the temperature according to the Flory-Huggins theory. The modeling allows for the calculation of the degree of protein transition for any temperature and moisture condition. The denaturation diagrams reflect the different protein compositions of lentil, chickpea, and bean (particularly the 11S/7S globulin ratio). Chickpea proteins were more thermally stable than those from lentil and bean. Proteins underwent an irreversible transition, suggesting that unfolding and aggregation were coupled.

Legume Seed Protein Digestibility as Influenced by Traditional and Emerging Physical Processing Technologies

The increased consumption of legume seeds as a strategy for enhancing food security, reducing malnutrition, and improving health outcomes on a global scale remains an ongoing subject of profound research interest. Legume seed proteins are rich in their dietary protein contents. However, coexisting with these proteins in the seed matrix are other components that inhibit protein digestibility. Thus, improving access to legume proteins often depends on the neutralisation of these inhibitors, which are collectively described as antinutrients or antinutritional factors. The determination of protein quality, which typically involves evaluating protein digestibility and essential amino acid content, is assessed using various methods, such as in vitro simulated gastrointestinal digestibility, protein digestibility-corrected amino acid score (IV-PDCAAS), and digestible indispensable amino acid score (DIAAS). Since most edible legumes are mainly available in their processed forms, an interrogation of these processing methods, which could be traditional (e.g., cooking, milling, extrusion, germination, and fermentation) or based on emerging technologies (e.g., high-pressure processing (HPP), ultrasound, irradiation, pulsed electric field (PEF), and microwave), is not only critical but also necessary given the capacity of processing methods to influence protein digestibility. Therefore, this timely and important review discusses how each of these processing methods affects legume seed digestibility, examines the potential for improvements, highlights the challenges posed by antinutritional factors, and suggests areas of focus for future research.

Effect of Transglutaminase Pre-Crosslinking Treatment Incorporated with Glucono-δ-lactone on the Physicochemical and Digestive Properties of Tofu

This study evaluated the effect of transglutaminase (TGase) pre-crosslinking treatment on the physicochemical and digestive characteristics of tofu coagulated by glucono-δ-lactone (GDL). Results showed that certain TGase pre-crosslinking times (0.5, 1, 2 and 3 h) could promote the colloidal stability of soymilk with increased particle average sizes and absolute values of zeta potential. Particularly, the water holding capacity and gel strength of tofu pre-crosslinked by TGase for 2 h were 6.8% and 47.7% enhancement, respectively, compared to the control, and exhibited the highest score of overall acceptability. However, extensive pre-crosslinking by TGase for 3 h had an adverse impact on the sensory of tofu with poor firmness, rough structure and whey separation. Hence, the tofu gel pre-crosslinked by TGase for 2 h and then coagulated by GDL was recommended which showed a "slow release" mode of soluble proteins during the in vitro digestion phase, and had more chances to release bioactive peptides than soymilk.

Physicochemical Properties and in vitro Digestibility of Myofibrillar Proteins From the Scallop Mantle (Patinopecten yessoensis) Based on Ultrahigh Pressure Treatment

The utilization of myofibrillar proteins (MPs) from the scallop mantle was limited due to its poor digestibility in vitro. In this study, structural properties and in vitro digestibility of MP were evaluated after modified by ultra-high pressure (UHP) at different pressures (0.1, 100, 200, 300, 400, and 500 MPa). The results showed that high pressure could significantly increase the ordered structure content like α-helix, inhibit the formation of disulfide bonds, and decrease surface hydrophobicity. Moreover, MP possessed the optimal solubility and in vitro digestibility properties at 200 MPa due to the minimum particle size and turbidity, relatively dense and uniform microstructure. The results indicated that the UHP treatment was an effective method to improve the digestibility of MP from scallop mantle and lay a theoretical basis for the functional foods development of poor digestion people and comprehensive utilization of scallop mantles.

Application of emerging technologies to obtain legume protein isolates with improved techno-functional properties and health effects

Current demand of consumers for healthy and sustainable food products has led the industry to search for different sources of plant protein isolates and concentrates. Legumes represent an excellent nonanimal protein source with high-protein content. Legume species are distributed in a wide range of ecological conditions, including regions with drought conditions, making them a sustainable crop in a context of global warming. However, their use as human food is limited by the presence of antinutritional factors, such as protease inhibitors, lectins, phytates, and alkaloids, which have adverse nutritional effects. Antitechnological factors, such as fiber, tannins, and lipids, can affect the purity and protein extraction yield. Although most are removed or reduced during alkaline solubilization and isoelectric precipitation processes, some remain in the resulting protein isolates. Selection of appropriate legume genotypes and different emerging and sustainable facilitating technologies, such as high-power ultrasound, pulsed electric fields, high hydrostatic pressure, microwave, and supercritical fluids, can be applied to increase the removal of unwanted compounds. Some technologies can be used to increase protein yield. The technologies can also modify protein structure to improve digestibility, reduce allergenicity, and tune technological properties. This review summarizes recent findings regarding the use of emerging technologies to obtain high-purity protein isolates and the effects on techno-functional properties and health.

Bioactive components in Bambara groundnut (Vigna subterraenea (L.) Verdc) as a potential source of nutraceutical ingredients

The utilization of nutraceuticals on a global scale has significantly increased over the past few years due to their reported health benefits and consumer's reluctance to consume synthetic drugs. This paper provides information regarding new and potential value added uses of biologically active compounds in Bambara groundnut (BGN) as ingredients that could be further researched and exploited for various applications. Nutraceutical is a food or part of food that apart from providing basic nutrients, offers medicinal benefits either by prevention and or treatment of an illness. BGN is a legume with rich nutrient profile that is under exploited industrially. It is widely used in African traditional medicine for its various health outcome, but has not been explored scientifically for its numerous nutraceutical potentials. Compared to beans BGN has greater quantity of soluble fiber and also have high dietary fiber. It is rich in polyphenolic compound which include flavonoids subgroups like flavonols, flavanols, anthocyanindins, isoflavones and phenolic acids: both benzoic acid and cinnamic acid derivatives, biologically active polyunsaturated fatty acids, proteins and peptides, antioxidant vitamins and minerals. The rising interest and emphasis in plant-based biologically active components (nutraceuticals) for various health promotion, has positioned this African legume as a potential source of nutraceutical ingredients (bioactive components) that could be exploited for improved nutrition and health.

Legume Proteins and Peptides as Compounds in Nutraceuticals: A Structural Basis for Dietary Health Effects

In the current climate of food security, quality aspects of legume crops have primary market economic and health impact. Legume proteins and peptides have been discovered to have a role far beyond supplying amino acids for growth and maintenance of body tissues. Several proteins (enzymatic inhibitors, lectins, storage globulins) and peptides derived from them (lunasin, hydrophobic peptides) have shown anticarcinogenic, hypocholesterolemic, glucose-lowering, antioxidant, antimicrobial, and immunostimulant properties. Further understanding of how structural features of legume proteins affect in vivo digestion and production of bioactive sequences represents a key step in the valorization of nutraceutical potentiality of legume proteins and peptides derived from them. In this work, the relationship between structure and bioavailability of protein and peptides are reviewed and discussed.

Immunomodulatory peptides-A promising source for novel functional food production and drug discovery

Immunomodulatory peptides are a complex class of bioactive peptides that encompasses substances with different mechanisms of action. Immunomodulatory peptides could also be used in vaccines as adjuvants which would be extremely desirable, especially in response to pandemics. Thus, immunomodulatory peptides in food of plant origin could be regarded both as valuable suplements of novel functional food preparation and/or as precursors or possible active ingredients for drugs design for treatment variety of conditions arising from impaired function of immune system. Given variety of mechanisms, different tests are required to assess effects of immunomodulatory peptides. Some of those effects show good correlation with in vivo results but others, less so. Certain plant peptides, such as defensins, show both immunomodulatory and antimicrobial effect, which makes them interesting candidates for preparation of functional food and feed, as well as templates for design of synthetic peptides.

The Exploitation of Orphan Legumes for Food, Income, and Nutrition Security in Sub-Saharan Africa

Poverty, food, and nutrition insecurity in sub-Saharan Africa (SSA) have become major concerns in recent times. The effects of climate change, drought, and unpredictable rainfall patterns threaten food production and sustainable agriculture. More so, insurgency, youth restiveness, and politico-economic instability amidst a burgeoning population requiring a sufficient and healthy diet remain front-burner issues in the region. Overdependence on only a few major staple crops is increasingly promoting the near extinction of many crops, especially orphan legumes, which possess immense potentials as protein and nutritional security crops. The major staple crops are declining in yield partly to their inability to adapt to the continuously changing climatic conditions. Remarkably, the orphan legumes are climate-smart crops with enormous agronomic features which foster sustainable livelihood. Research efforts on these crops have not attained a reasonable comparative status with most commercial crops. Though many research organizations and scientists have made efforts to promote the improvement and utilization of these orphan legumes, there is still more to be done. These legumes' vast genetic resources and economic utility are grossly under-exploited, but their values and promising impacts are immeasurable. Given the United Nations sustainable development goals (SDGs) of zero hunger, improved nutrition, health, and sustainable agriculture, the need to introduce these crops into food systems in SSA and other poverty-prone regions of the world is now more compelling than ever. This review unveils inherent values in orphan legumes needing focus for exploitation viz-a-viz cultivation, commercialization, and social acceptance. More so, this article discusses some of the nutraceutical potentials of the orphan legumes, their global adaptability, and modern plant breeding strategies that could be deployed to develop superior phenotypes to enrich the landraces. Advanced omics technologies, speed breeding, as well as the application of genome editing techniques, could significantly enhance the genetic improvement of these useful but underutilized legumes. Efforts made in this regard and the challenges of these approaches were also discussed.

Impact of solid-state fermentation on factors and mechanisms influencing the bioactive compounds of grains and processing by-products

Cereal and legume grains and their processing by-products are rich sources of bioactives such as phenolics with considerable health potential, but these bioactives suffer from low bioaccessibility and bioavailability, resulting in limited use. Several studies have demonstrated that solid-state fermentation (SSF) with food-grade microorganisms is effective in releasing bound phenolic compounds in cereal and legume products. In this review, we discuss the effect of SSF on cereal and legume grains and their by-products by examining the role of specific microorganisms, their hydrolytic enzymes, fermentability of agri-food substrates, and the potential health benefits of SSF-enhanced bioactive compounds. SSF with fungi (Aspergillus spp. and Rhizopus spp.), bacteria (Bacillus subtilis and lactic acid bacteria (LAB) spp.) and yeast (Saccharomyces cerevisiae) significantly increased the bioactive phenolics and antioxidant capacities in cereal and legume grains and by-products, mainly through carbohydrate-cleaving enzymes. Increased bioactive phenolic and peptide contents of SSF-bioprocessed cereal and legume grains have been implicated for improved antioxidant, anti-inflammatory, anti-carcinogenic, anti-diabetic, and angiotensin-converting-enzyme (ACE) inhibitory effects in fermented agri-food products, but these remain as preliminary results. Future research should focus on the microbial mechanisms, suitability of substrates, and the physiological health benefits of SSF-treated grains and by-products.