Black bean (Phaseolus vulgaris L.) protein hydrolysates: Physicochemical and functional properties

Unveiling the potential of bean proteins: Extraction methods, functional and structural properties, modification techniques, physiological benefits, and diverse food applications

Bean proteins, known for their sustainability, versatility, and high nutritional value, represent a valuable yet underutilized resource, receiving less industrial attention compared to soy and pea proteins. This review examines the structural and molecular characteristics, functional properties, amino acid composition, nutritional value, antinutritional factors, and digestibility of bean proteins. Their applications in various food systems, including baked goods, juice and milk substitutes, meat alternatives, edible coatings, and 3D printing inks, are discussed. The physiological benefits of bean proteins, such as antidiabetic, cardioprotective, antioxidant, and neuroprotective effects, are also presented, highlighting their potential for promoting well-being. Our review emphasizes the diversity of bean proteins and highlights ultrasound as the most effective extraction method among available techniques. Beyond their physiological benefits, bean proteins significantly enhance the structural, technological, and nutritional properties of food systems. The functionality can be further improved through various modification techniques, thereby expanding their applicability in the food industry. While studies have explored the impact of bean protein structure on their nutritional and functional properties, further research is needed to investigate advanced modification techniques and the structure-function relationship. This will enhance the utilization of bean proteins in innovative and sustainable food applications.

Metabolomics of black beans (Phaseolus vulgaris L.) during atmospheric pressure steaming and in vitro simulated digestion

In the paper, metabolomics techniques based on UHPLC-QE-MS were used to study raw black beans, steaming black beans, and their in vitro digestion products. The results show that the three groups of raw black beans, atmospheric pressure-steamed black beans, and their in vitro digests comprised 922, 945, and 878 characteristic metabolites, respectively, dominated by amino acids, organic acids, polyphenols, and sugars. After screening the differential metabolites, content comparison, the content of amino acids, sugars, and phenolics in black beans was found to be increased after atmospheric steaming. During in vitro digestion, the amino acid content increased and the phenolic content decreased, with amino acid synthesis, phenolic degradation, and conversion predominating. This study provides data to support the changes in black beans metabolites during atmospheric steam processing and in vitro digestion.

Effects of ultrasonic waves of different powers on the physicochemical properties, functional characteristics, and ultrastructure of bovine liver peptides

In recent years, ultrasound has emerged as a widely used technology for modifying proteins/peptides. In this study, we focused on the intrinsic mechanism of ultrasound-induced modification of bovine liver peptides, which were treated with ultrasound power of 0, 100, 200, 300, 400, and 500 W, and their physicochemical and functional properties, as well as ultrastructures, were investigated. The results show that ultrasound mainly affects hydrogen bonding and hydrophobic interactions to change the conformation of proteins and unfolds proteins through a cavitation effect, leading to an increase in biological activity. Fourier infrared spectroscopy showed that ultrasound inhibited the formation of hydrogen bonds and reduced intermolecular cross-linking. Molecular weight distribution showed that the antioxidant components of bovine liver polypeptides were mainly concentrated in fractions of 500-1,000 Da. Maximum values of ABTS (82.66 %), DPPH (76.02 %), chelated iron (62.18 %), and reducing power (1.2447) were obtained by treating bovine liver polypeptides with 500 W ultrasound. Combined with the scanning electron microscopy results, with the intervention of ultrasound, the impact force generated by ultrasonication may lead to the loosening of the protein structure, which further promotes the release of antioxidant peptides, and these findings provide new insights into the application of ultrasound in the release of antioxidant peptides from bovine liver.

Physicochemical, nutraceutical, and sensory evaluation of a milk-type plant-based beverage of extruded common bean (Phaseolus vulgaris L.) added with iron

Milk-type beverages are popular vegan products requiring iron and calcium fortification to improve their nutritional value, as iron deficiency is the world's most prevalent nutritional problem. This research aimed to develop and characterize an extruded common bean (Phaseolus vulgaris L.)-based milk-type beverage added with bean protein isolate and iron. The formulations included flavors (non-flavored, vanilla, and nut) and two iron concentrations (2 and 3 mg FeSO4/100 mL). Extrusion increased the beverages' protein (+17.38 %) and starch digestibility, and reduced their antinutritional compounds (trypsin inhibitors, condensed tannins, and carbonates). Developed beverages' formulations differed from a commercial soybean beverage in their physicochemical properties but were more nutritious (protein: 3.33-3.44 %; fiber: 3.43-4.08 %). Iron-added beverages displayed a medium sensory acceptance (best overall likeness: 5.3-6.2). The developed beverage is a suitable, sensory-accepted, and nutritious bean-based beverage, suggesting novel research lines improving vegan beverage formulations to increase average daily iron intake.

Technical-functional and surface properties of white common bean proteins (Phaseolus vulgaris L.): Effect of pH, protein concentration, and guar gum presence

Legumes are abundant sources of proteins, and white common bean proteins play an important role in air-water interface properties. This study aims to investigate the technical-functional properties of white common bean protein isolate (BPI) as a function of pH, protein concentration, and guar gum (GG) presence. BPI physicochemical properties were analyzed in terms of solubility, zeta potential, and mean particle diameter at pH ranging from 2 to 9, in addition to water-holding capacity (WHC), oil-holding capacity (OHC), and thermogravimetric analysis. Protein dispersions were evaluated in terms of dynamic, interfacial, and foam-forming properties. BPI showed higher solubility (>80 %) at pH 2 and above 7. Zeta potential and mean diameter ranged from 15.43 to -34.08 mV and from 129.55 to 139.90 nm, respectively. BPI exhibited WHC and OHC of 1.37 and 4.97 g/g, respectively. Thermograms indicated decomposition temperature (295.81 °C) and mass loss (64.73 %). Flow curves indicated pseudoplastic behavior, with higher η100 values observed in treatments containing guar gum. The behavior was predominantly viscous (tg δ > 1) at lower frequencies, at all pH levels, shifting to predominantly elastic at higher frequencies. Equilibrium surface tension (γeq) ranged from 43.87 to 41.95 mN.m-1 and did not decrease with increasing protein concentration under all pH conditions. All treatments exhibited ϕ < 15°, indicating predominantly elastic surface films. Foaming properties were influenced by higher protein concentration and guar gum addition, and the potential formation of protein-polysaccharide complexes favored the kinetic stability of the system.

Incorporation of spray-dried encapsulated bioactive peptides from coconut (Cocos nucifera L.) meal by-product in bread formulation

This study aimed to stabilize and mask the bitterness of peptides obtained from the enzymatic hydrolysis of coconut-meal protein with maltodextrin (MD) and maltodextrin-pectin (MD-P) as carriers via spray-drying. Essential (~35%), hydrophobic (~32%), antioxidant (~15%), and bitter (~45%) amino acids comprised a significant fraction of the peptide composition (with a degree of hydrolysis of 33%). The results indicated that the peptide's production efficiency, physical and functional properties, and hygroscopicity improved after spray-drying. Morphological features of free peptides (fragile and porous structures), spray-dried with MD (wrinkled with indented structures), and MD-P combination (relatively spherical particles with smooth surfaces) were influenced by the process type and feed composition. Adding free and microencapsulated peptides to the bread formula (2% W/W) caused changes in moisture content (35%-43%), water activity (0.89-0.94), textural properties (1-1.6 N), specific volume (5.5-6 cm3/g), porosity (18%-27%), and color indices of the fortified product. MD-P encapsulated peptides in bread fortification resulted in thermal stability and increased antioxidant activity (DPPH and ABTS+ radical scavenging: 4.5%-39.4% and 31.6%-46.8%, respectively). MD-P (as a carrier) could maintain sensory characteristics and mask the bitterness of peptides in the fortified bread. The results of this research can be used to produce functional food and diet formulations.

Use of olive and sunflower protein hydrolysates for the physical and oxidative stabilization of fish oil-in-water emulsions

BACKGROUND

Olive and sunflower seeds are by-products generated in large amounts by the plant oil industry. The technological and biological properties of plant-based substrates, especially protein hydrolysates, have increased their use as functional ingredients for food matrices. The present study evaluates the physical and oxidative stabilities of 50 g kg-1 fish oil-in-water emulsions where protein hydrolysates from olive and sunflower seeds were incorporated at 20 g kg-1 protein as natural emulsifiers. The goal was to investigate the effect of protein source (i.e. olive and sunflower seeds), enzyme (i.e. subtilisin and trypsin) and degree of hydrolysis (5%, 8% and 11%) on the ability of the hydrolysate to stabilize the emulsion and retard lipid oxidation over a 7-day storage period.

RESULTS

The plant protein hydrolysates displayed different emulsifying and antioxidant capacities when incorporated into the fish oil-in-water emulsions. The hydrolysates with degrees of hydrolysis (DH) of 5%, especially those from sunflower seed meal, provided higher physical stability, regardless of the enzymatic treatment. For example, the average D [2, 3] values for the emulsions containing sunflower subtilisin hydrolysates at DH 5% only slightly increased from 1.21 ± 0.02 μm (day 0) to 2.01 ± 0.04 μm (day 7). Moreover, the emulsions stabilized with sunflower or olive seed hydrolysates at DH 5% were stable against lipid oxidation throughout the storage experiment, with no significant variation in the oxidation indices between days 0 and 4.

CONCLUSION

The results of the present study support the use of sunflower seed hydrolysates at DH 5% as natural emulsifiers for fish oil-in-water emulsions, providing both physical and chemical stability against lipid oxidation. © 2024 Society of Chemical Industry.

Structure, physicochemical properties, and biological activities of protein hydrolysates from Zanthoxylum seed

BACKGROUND

Zanthoxylum seed, as a low-cost and easily accessible plant protein resource, has good potential in the food industry. But protein and its hydrolysates from Zanthoxylum seed are underutilized due to the dearth of studies on them. This study aimed to investigate the structure and physicochemical and biological activities of Zanthoxylum seed protein (ZSP) hydrolysates prepared using Protamex®, Alcalase®, Neutrase®, trypsin, or pepsin.

RESULTS

Hydrolysis using each of the five enzymes diminished average particle size and molecular weight of ZSP but increased random coil content. ZSP hydrolysate prepared using pepsin had the highest degree of hydrolysis (24.07%) and the smallest molecular weight (<13 kDa) and average particle size (129.80 nm) with the highest solubility (98.9%). In contrast, ZSP hydrolysate prepared using Alcalase had the highest surface hydrophobicity and foaming capacity (88.89%), as well as the lowest foam stability (45.00%). Moreover, ZSP hydrolysate prepared using Alcalase exhibited the best hydroxyl-radical scavenging (half maximal inhibitory concentration (IC50 ) 1.94 mg mL-1 ) and ferrous-ion chelating (IC50 0.61 mg mL-1 ) activities. Additionally, ZSP hydrolysate prepared using pepsin displayed the highest angiotensin-converting enzyme inhibition activity (IC50 0.54 mg mL-1 ).

CONCLUSION

These data showed that enzyme hydrolysis improved the physicochemical properties of ZSP, and enzymatic hydrolysates of ZSP exhibited significant biological activity. These results provided validation for application of ZSP enzymatic hydrolysates as antioxidants and antihypertensive agents in the food or medicinal industries. © 2023 Society of Chemical Industry.

Degree of hydrolysis is a poor predictor of the sensitizing capacity of whey- and casein-based hydrolysates in a Brown Norway rat model of cow's milk allergy

The use of infant formulas (IFs) based on hydrolyzed cow's milk proteins to prevent cow's milk allergy (CMA) is highly debated. The risk of sensitization to milk proteins induced by IFs may be affected by the degree of hydrolysis (DH) as well as other physicochemical properties of the cow's milk-based protein hydrolysates within the IFs. The immunogenicity (specific IgG1 induction) and sensitizing capacity (specific IgE induction) of 30 whey- or casein-based hydrolysates with different physicochemical characteristics were compared using an intraperitoneal model of CMA in Brown Norway rats. In general, the whey-based hydrolysates demonstrated higher immunogenicity than casein-based hydrolysates, inducing higher levels of hydrolysate-specific and intact-specific IgG1. The immunogenicity of the hydrolysates was influenced by DH, peptide size distribution profile, peptide aggregation, nano-sized particle formation, and surface hydrophobicity. Yet, only the surface hydrophobicity was found to affect the sensitizing capacity of hydrolysates, as high hydrophobicity was associated with higher levels of specific IgE. The whey- and casein-based hydrolysates exhibited distinct immunological properties with highly diverse molecular composition and physicochemical properties which are not accounted for by measuring DH, which was a poor predictor of sensitizing capacity. Thus, future studies should consider and account for physicochemical characteristics when assessing the sensitizing capacity of cow's milk-based protein hydrolysates.

Interaction of the extracellular protease from Staphylococcus xylosus with meat proteins elucidated via spectroscopic and molecular docking

This study aimed to assess the effect of an external protease secreted by Staphylococcus (S.) xylosus on the hydrolysis and flavor properties of meat protein. The results indicated that the protease significantly increased the solubility of myofibrillar proteins (MPs) and sarcoplasmic proteins (SPs) in water (P < 0.05), and altered their surface hydrophobicity and secondary structure. The results of micromorphological and free amino acids analyses suggested that the protease degraded the large and insoluble meat protein aggregates into small molecular proteins with uniform distribution and amino acids, especially glycine, glutamic acid, leucine, and cysteine. Moreover, the protease-catalyzed hydrolysis promoted the formation of some volatile compounds in the MPs and SPs. Additionally, molecular docking analysis suggested that hydrogen bond and hydrophobic interaction promoted the formation of a S. xylosus protease/meat protein complex. These results provided a basis for the future application of S. xylosus protease in meat products.

Influence of starch-protein interactions on the digestibility and chemical properties of a 3D-printed food matrix based on salmon by-product proteins

This study evaluated the influence of starch-protein interactions on the chemical properties and digestibility of a 3D-printed gel based on salmon by-product protein. Changes in the starch-protein interactions of the stable cornstarch (CS, 15%) and salmon protein isolate (SPI, 4%-12%) printable gels during the in vitro gastrointestinal digestion process were studied by principal component analysis. Protein-rich printed gels increased resistant starch content by 18.05%. Changes in chemical properties and the starch-protein concentration of the gels during the digestion process were highly correlated. The CS-SPI gels in the gastric and intestinal phases exhibited lower α-helix/β-sheet ratio and fluorescence intensity values, whereas surface hydrophobicity increased. This resulted in more ordered structures with a high level of molecular interaction that inhibited enzymatic hydrolysis. This study provides crucial information about the transformations of starch-protein interactions during the digestibility of 3D-printed food matrices as an alternative source of nutrients with a high nutritional quality.

Lipid-Induced Oxidative Modifications Decrease the Bioactivities of Collagen Hydrolysates from Fish Skin: The Underlying Mechanism Based on the Proteomic Strategy

Collagen peptides exhibit various bioactivities, including antioxidation and ACE inhibition. However, the bioactivities of collagen peptides decrease gradually due to oxidation deterioration during storage, and this degradation of bioactive peptides is rarely studied. In this study, the oxidative levels and the bioactivities of collagen peptides were investigated during an oxidative-induced storage accelerated by lipids. The results suggested that the oxidation of collagen peptides was divided into three stages. At the early stage, the carbonyl content of collagen peptides increased rapidly (from 2.32 to 3.72 μmol/g peptide), showing a close correlation with their bioactivities (for antioxidation, r = -0.947; for ACE inhibition, r = -0.911). The oxidation level in the middle stage continued but was stable, and the bioactivities decreased. At the later stage, the Schiff base and dityrosine content increased significantly and showed a strong correlation with the bioactivities (antioxidation, r = -0.820, -0.801; ACE inhibition, r = -0.779, -0.865). The amino acid and proteomic analyses showed that Met, Lys, and Arg were susceptible to oxidation and revealed their oxidative modification types. This study provided an insight into the dynamic oxidative modifications of collagen peptides, which were shown to correlate well with the change in bioactivities.

Non-starch polysaccharides from kidney beans: comprehensive insight into their extraction, structure and physicochemical and nutritional properties

Kidney beans (Phaseolus vulgaris L.) are an important legume source of carbohydrates, proteins, and bioactive molecules and thus have attracted increasing attention for their high nutritional value and sustainability. Non-starch polysaccharides (NSPs) in kidney beans account for a high proportion and have a significant impact on their biological functions. Herein, we critically update the information on kidney bean varieties and factors that influence the physicochemical properties of carbohydrates, proteins, and phenolic compounds. Furthermore, their extraction methods, structural characteristics, and health regulatory effects, such as the regulation of intestinal health and anti-obesity and anti-diabetic effects, are also summarized. This review will provide suggestions for further investigation of the structure of kidney bean NSPs, their relationships with biological functions, and the development of NSPs as novel plant carbohydrate resources.

Protection of navy-bean bioactive peptides within nanoliposomes: morphological, structural and biological changes

This study aimed to produce bioactive peptides from navy-bean protein with alcalase and pepsin enzymes (30-300 min) and to load them into a nanoliposome system to stabilize and improve their bioavailability. The degree of hydrolysis and biological activities (scavenging of DPPH, OH, and ABTS free radicals, reducing power, and chelating metal ions) of navy-bean protein were affected by the type of enzyme and hydrolysis time. The average particle size (83-116 nm), PDI (0.23-0.39), zeta potential (- 13 to - 20 mV), and encapsulation efficiency (80-91%) of nanoliposomes were influenced by the type and charge of peptides. The storage temperature and the type of loaded peptide greatly affected the physical stability of nanocarriers and maintaining EE during storage. The FTIR results suggested the effect of enzymatic hydrolysis on the secondary structures of protein and the effective placement of peptides inside polar-regions and the phospholipid monolayer membrane. SEM images showed relatively uniform-sized particles with irregular structures, which confirmed the results of DLS. The antioxidant activity of primary peptides affected the free radical scavenging of loaded nanoliposomes. Liposomes loaded with navy-bean peptides can be used as a health-giving formula in enriching all kinds of drinks, desserts, confectionery products, etc.

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.

Prospects on emerging eco-friendly and innovative technologies to add value to dry bean proteins

The world's growing population and evolving food habits have created a need for alternative plant protein sources, with pulses playing a crucial role as healthy staple foods. Dry beans are high-protein pulses rich in essential amino acids like lysine and bioactive peptides. They have gathered attention for their nutritional quality and potential health benefits concerning metabolic syndrome. This review highlights dry bean proteins' nutritional quality, health benefits, and limitations, focusing on recent eco-friendly emerging technologies for their obtaining and functionalization. Antinutritional factors (ANFs) in bean proteins can affect their in vitro protein digestibility (IVPD), and lectins have been identified as potential allergens. Recently, eco-friendly emerging technologies such as ultrasound, microwaves, subcritical fluids, high-hydrostatic pressure, enzyme technology, and dry fractionation methods have been explored for extracting and functionalizing dry bean proteins. These technologies have shown promise in reducing ANFs, improving IVPD, and modifying allergen epitopes. Additionally, they enhance the techno-functional properties of bean proteins, making them more soluble, emulsifying, foaming, and gel-forming, with enhanced water and oil-holding capacities. By utilizing emerging innovative technologies, protein recovery from dry beans and the development of protein isolates can meet the demand for alternative protein sources while being eco-friendly, safe, and efficient.

Structural properties and antioxidant activities of soybean protein hydrolysates produced by Lactobacillus delbrueckii subsp. bulgaricus cell envelope proteinase

In this work, we investigated the structural and biological properties of soybean protein isolate (SPI) after 0-8 h hydrolyzation with cell envelope proteinase (CEP) extracted from Lactobacillus delbrueckii subsp. bulgaricus. CEP hydrolysis increased the β-sheet and red-shifted the fluorescence peak, while decreasing the α-helix, indicating the unfolding of soybean proteins. Increased surface hydrophobicity and fluorescence of the soybean protein hydrolysates were correlated with the increased hydrophobic amino acid (from 209.67 to 217.6 mg/100 g). CEP tended to hydrolyze the N- and C-terminal regions of sequences dominated by Gly and Leu, which enhanced the antioxidant activity of the SPHs (lowest IC_50s value of ABTS^•+ and hydroxyl radical scavenging activity were 0.324 ± 0.006 mg/mL and 0.365 ± 0.001 mg/mL after 4 h hydrolysis). Comparison with the database of bioactive peptides suggested various potential biological activities, including antioxidant activity, angiotensin-converting enzyme inhibitory activity and dipeptidyl peptidase-IV inhibitory activity. The study findings have theoretical significance for the development of CEP hydrolysis and novel bioactive soybean peptides.

Enzymatic hydrolysis of soy and chickpea protein with Alcalase and Flavourzyme and formation of hydrogen bond mediated insoluble aggregates

Food applications involving plant proteins require modification of their functionality to mimic the unique properties of animal proteins. Enzymatic hydrolysis is commonly used to alter the functionality of plant proteins, particularly to improve their solubility near the isoelectric point. Current methodological approaches mostly indicate improved solubility upon hydrolysis. However, published methods include the removal of insoluble material before analysis, and calculations are based on only the solubilized material as a percentage of the filtered protein. This approach artificially increases solubility estimation and gives an incorrect assessment of the efficacy of hydrolysis. By using the total amount of protein, this study aims to determine the effect of two microbial proteases, Flavourzyme and Alcalase, on the solubility and structural and thermal properties of soy and chickpea proteins. Protein isolates were first extracted from soy and chickpea flour and hydrolyzed from 0 to 3 h. Then, their degree of hydrolysis and solubility at a range of pHs were determined using the o-phthaldialdehyde (OPA) and Lowry methods, respectively. Proteins' electrophoretic mobility, protein-protein interactions, thermal properties, and protein secondary structures were also determined. Solubility decreased over time though the solubility of the hydrolysate improved near the isoelectric point. Soy Flavourzyme hydrolysates remained the most soluble and chickpea Flavourzyme hydrolysates showed the least solubility. Thermal data suggested that Alcalase reduced the protein denaturation temperature, leading to a loss of solubility upon thermal enzyme inactivation. The loss of solubility of hydrolysates was strongly associated with hydrogen bonding, which may result from the formation of polar peptide termini. These results challenge commonly accepted beliefs that hydrolysis inevitably improves solubility of plant proteins. Instead, it is shown that hydrolysis causes structural changes that result in aggregation, thus potentially limiting the application of enzymatic hydrolysis without the addition of further processing methods.

Impact of Cavitation Jet on the Structural, Emulsifying Features and Interfacial Features of Soluble Soybean Protein Oxidized Aggregates

A cavitation jet can enhance food proteins' functionalities by regulating solvable oxidized soybean protein accumulates (SOSPI). We investigated the impacts of cavitation jet treatment on the emulsifying, structural and interfacial features of soluble soybean protein oxidation accumulate. Findings have shown that radicals in an oxidative environment not only induce proteins to form insoluble oxidative aggregates with a large particle size and high molecular weight, but also attack the protein side chains to form soluble small molecular weight protein aggregates. Emulsion prepared by SOSPI shows worse interface properties than OSPI. A cavitation jet at a short treating time (<6 min) has been shown to break the core aggregation skeleton of soybean protein insoluble aggregates, and insoluble aggregates into soluble aggregates resulting in an increase of emulsion activity (EAI) and constancy (ESI), and a decrease of interfacial tension from 25.15 to 20.19 mN/m. However, a cavitation jet at a long treating time (>6 min) would cause soluble oxidized aggregates to reaggregate through an anti-parallel intermolecular β-sheet, which resulted in lower EAI and ESI, and a higher interfacial tension (22.44 mN/m). The results showed that suitable cavitation jet treatment could adjust the structural and functional features of SOSPI by targeted regulated transformation between the soluble and insoluble components.

Improving the Functional Performance of Date Seed Protein Concentrate by High-Intensity Ultrasonic Treatment

Date kernel is a plant-derived byproduct that has the potential to be converted into a high-value-added food ingredient, such as protein concentrate, in the food industry. Ultrasound, which is an alternative method for improving the functional properties of food proteins, is an effective physical treatment for modifying protein functionality. Solubility is the main criterion that primarily affects other functional properties of protein concentrates, such as emulsification, foaming, and water and oil binding. The aim of this study is to enhance the techno-functional performance of date seed protein concentrate (DSPC) by maximizing the solubility via a high-intensity ultrasound (HIUS) treatment at a fixed frequency of 20 kHz. The effect of ultrasonic homogenization under varying amplitudes and times (amplitude of 40, 60, and 80% for 5, 10, and 15 min, respectively) on the functional properties of the DSPC was investigated by using the response surface methodology (RSM). A face-centered central composite design (FC-CCD) revealed that the optimal process conditions of HIUS were at an amplitude of 80% for 15 min. The physicochemical and functional properties of the ultrasound-applied concentrate (DSPC-US) were determined under the optimum HIUS conditions, and then these properties of DSPC-US were compared to the native DSPC. The results showed that the solubility of all DSPC samples treated by HIUS was significantly (p < 0.05) higher than that of the native DSPC. In addition, emulsion activity/stability, foaming activity/stability, and oil-binding capacity increased after HIUS homogenization treatments, whereas the water-binding capacity decreased. These changes in the techno-functional properties of the DSPC-US were explained by the modification to the physicochemical structure of the DSPC (particle size, zeta potential, SDS-PAGE, SEM, FTIR, DSC, free SH content, surface hydrophobicity, and intrinsic emission). This work revealed that HIUS could be an effective treatment for enhancing the functional properties of date seed protein concentrate.

Nutrient and popping characteristics of Wyoming-grown Peruvian popping beans

American consumers fall short of dietary fiber intake recommended by dietary guidelines. Beans provide protein and fiber, however, less than 14% of adults include them in their daily diets. Nuña beans (Phaseolus vulgaris L.), a class of common beans originated in South America and cultivated for growth in North America, possess a unique set of characteristics including flavor profile, popping ability, and nutrient content that may appeal to consumers. The purpose of this study was to evaluate a unique line of Wyoming-grown popping beans to (1) determine nutrient characteristics and (2) assess popping percentage and shelf stability. Crude protein content was determined for five lines grown in Wyoming utilizing the Dumas method for nitrogen quantification. Total fatty acid content and a fatty acid profile for one line (CO49957) was determined by gas-liquid chromatography. Popping percentage was assessed by heating beans in canola oil in a cast iron pan to induce popping. Storage duration impact on popping was evaluated on CO49957 at 6, 12, and 15 months after harvest. Crude protein content was significantly different between all five lines. Total fatty acid content of CO49957 averaged 2.90 g/100 g wet weight. Average fatty acid profile of CO49957 popped in canola oil comprised oleic acid (41.4%), linoleic acid (20.4%), α-linolenic acid (18.6%), palmitic acid (10.4%), and stearic acid (2.23%). Popping percentage was 90% (baseline), 100% (6 months), 87% (12 months), and 80% (15 months). Popping beans provide plant-based protein and fiber while maintaining adequate levels of popping percentage with prolonged storage.

Modification of Whey Proteins by Sonication and Hydrolysis for the Emulsification and Spray Drying Encapsulation of Grape Seed Oil

In this study, whey protein concentrate (WPC) was sonicated or partially hydrolyzed by Alcalase, then examined as an emulsifier and carrier for the emulsification and spray drying of grape seed oil (GSO)-in-water emulsions. The modification treatments increased the free amino acid content and antioxidant activity (against DPPH and ABTS free radicals), as well as, the solubility, emulsifying, and foaming activities of WPC. The modified WPC-stabilized emulsions had smaller, more homogeneous droplets and a higher zeta potential as compared to intact WPC. The corresponding spray-dried powders also showed improved encapsulation efficiency, oxidative stability, reconstitution ability, flowability, solubility, and hygroscopicity. The morphology of particles obtained from the primary WPC (matrix type, irregular with surface pores) and modified WPC (reservoir type, wrinkled with surface indentations), as well as the oxidative stability of the GSO were influenced by the functional characteristics and antioxidant activity of the carriers. Changes in the secondary structures and amide regions of WPC, as well as the embedding of GSO in its matrix, were deduced from FTIR spectra after modifications. Partial enzymolysis had better results than ultrasonication; hence, the WPC hydrolysates are recommended as emulsifiers, carriers, and antioxidants for the delivery and protection of bioactive compounds.

Bioactive and health-promoting properties of enzymatic hydrolysates of legume proteins: a review

This study comprehensively reviewed the effect of controlled enzymatic hydrolysis on the bioactivity of pulse protein hydrolysates (PPHs). Proteolysis results in the partial structural unfolding of pulse proteins with an increase in buried hydrophobic groups of peptide sequences. The use of PPHs in a dose-dependent manner can enhance free radical scavenging and improve antioxidant activities regarding inhibition of lipid oxidation, ferric reducing power, metal ion chelation, and β-carotene bleaching inhibition. Ultrafiltered peptide fractions with low molecular weights imparted angiotensin-I converting enzyme (ACE) inhibitory effects during in vitro simulated gastrointestinal digestion and in vivo conditions. Ultrasonication, high-pressure pretreatments, and glycosylation as post-treatments can improve the antiradical, antioxidant, and ACE inhibitory activities of PPHs. The electrostatic attachment of pulse peptides to microbial cells can inhibit the growth and activity of bacteria and fungi. Bioactive pulse peptides can reduce serum cholesterol and triglycerides, and inhibit the formation of adipocyte lipid storage, allergenic factors, inflammatory markers, and arterial thrombus without cytotoxicity. The combination of germination and enzymatic hydrolysis can significantly increase the protein digestibility and bioavailability of essential amino acids. Moreover, the utilization and enrichment of bakery and meat products with functional PPHs ensure quality, safety, and health aspects of food products.

Effect of enzymatic hydrolysis conditions on structure of soy protein isolate/gum arabic complex and stability of oil-in-water emulsion

BACKGROUND

The emulsifying, antioxidant and foaming properties of soy protein isolate hydrolysates (SPH) can be improved by the addition of gum arabic (GA). We investigated the effects of different hydrolysis conditions on the complexation of SPH and GA, and the effects of the complex on the properties of emulsions.

RESULTS

Fluorescence spectroscopy showed that the addition of GA had a stronger effect on bromelain and pepsin hydrolysates than trypsin hydrolysate, and therefore had a higher binding constant (K_A ) and a larger number of binding sites (n). The addition of GA could also improve protein solubility and emulsifying ability. The emulsions prepared with complexes, especially the complex of GA and SPH obtained by pepsin hydrolysis for 3 h, had a high absolute charge value, uniform particle size distribution, stable morphology, and good storage stability. After storage, the emulsification index (CI) of the emulsion only increased to 23.08%; its 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity was 24.37 ± 1.22% and its 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS⁺ ) free radical scavenging activity was largely retained.

CONCLUSION

During long-term storage, pepsin-treated protein (especially protein treated for 3 h) and GA can form a stable emulsion with antioxidant properties. This work provides new ideas for the development of natural and safe emulsifiers that have antioxidant properties and can be stored long-term and used in the food industry. © 2022 Society of Chemical Industry.

Interaction between protease from Staphylococcus epidermidis and pork myofibrillar protein: Flavor and molecular simulation

This study investigated the influence of a protease from Staphylococcus (S.) epidermidis on the hydrolysis and flavor development in pork myofibrillar protein (MP). The surface hydrophobicity, fluorescence, Fourier transform infrared spectra, and atomic force microscopy analysis indicated that hydrolysis significantly changed surface hydrophobicity and secondary structure of MP (p < 0.05), and improved the stability of MP in water. The contents of free amino acid from MP, especially glutamic and alanine, significantly increased (p < 0.05), and the production of volatile compound such as aldehydes, alcohols and acid were promoted under the action of protease. MP treated with S. epidermidis protease is non-cytotoxic to the HEK-293 cells. Molecular docking analysis suggested that the interaction between the protease and actin was spontaneous and mainly involved hydrogen bonding forces. In summary, this study provides a theoretical basis for the future application of S. epidermidis protease in fermented meat products.

The Preservative Action of Protein Hydrolysates from Legume Seed Waste on Fresh Meat Steak at 4 °C: Limiting Unwanted Microbial and Chemical Fluctuations

Valorizing agricultural wastes to preserve food or to produce functional food is a general trend regarding the global food shortage. Therefore, natural preservatives were developed from the seed waste of the cluster bean and the common bean to extend the shelf life of fresh buffalo meat steak and boost its quality via immersion in high-solubility peptides, cluster bean protein hydrolysate (CBH), and kidney bean protein hydrolysate (RCH). The CBH and the RCH were successfully obtained after 60 min of pepsin hydrolysis with a hydrolysis degree of 27−30%. The SDS-PAGE electropherogram showed that at 60 min of pepsin hydrolysis, the CBH bands disappeared, and RCH (11−48 kD bands) nearly disappeared, assuring the high solubility of the obtained hydrolysates. The CBH and the RCH have considerable antioxidant activity compared to ascorbic acid, antimicrobial activity against tested microorganisms compared to antibiotics, and significant functional properties. The CBH and the RCH (500 µg/mL) successfully scavenged 93 or 89% of DPPH radicals. During the 30-day cold storage (4 °C), the quality of treated and untreated fresh meat steaks was monitored. Protein hydrolysates (500 g/g) inhibited lipid oxidation by 130−153% compared to the control and nisin and eliminated 31−55% of the bacterial load. The CBH and the RCH (500 µg/g) significantly enhanced meat redness (a* values). The protein maintained 80−90% of the steak’s flavor and color (p < 0.05). In addition, it increased the juiciness of the steak. CBH and RCH are ways to valorize wastes that can be safely incorporated into novel foods.

Protein Hydrolysates Derived from Animals and Plants—A Review of Production Methods and Antioxidant Activity

There is currently considerable interest on the use of animal, plant, and fungal sources in the production of bioactive peptides, as evidenced by the substantial body of research on the topic. Such sources provide cheap and environmentally friendly material as it often includes waste and by-products. Enzymatic hydrolysis is considered an efficient method of obtaining peptides capable of antioxidant activity. Those properties have been proven in terms of radical-scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis-(3-ethyl-benzothiazoline-6-sulphonic acid)), hydroxyl and superoxide radical methods. Additionally, the reducing power, ferrous ion-chelating (FIC), ferric reducing antioxidant power (FRAP), and the ability of the protein hydrolysates to inhibit lipid peroxidation have also been explored. The results collected in this review clearly indicate that the substrate properties, as well as the conditions under which the hydrolysis reaction is carried out, affect the final antioxidant potential of the obtained peptides. This is mainly due to the structural properties of the obtained compounds such as size or amino acid sequences.

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.

Exploring the Antioxidant and Structural Properties of Black Bean Protein Hydrolysate and Its Peptide Fractions

A great deal of attention has been paid to charactering the protein hydrolysates prepared by enzymatic hydrolysis, while the influence of molecular weight (MW) distributions on the resultant hydrolysates remains unclear. This study aimed to explore the physicochemical and antioxidant characteristics of protein hydrolysate and its peptide fractions. Bromelain has been commonly used to hydrolyze black bean protein via response surface methodology (RSM). The optimal hydrolysis parameters were observed at 52°C, pH 7, E/S ratio of 2.2 (ratio of enzyme to substrate), and 4 h. Under these parameters, the hydrolysate (BPH) presented DPPH radical scavenging activity and Fe²⁺ chelating activity with IC₅₀ values of 100.08 ± 2.42 and 71.49 ± 0.81 μg/mL, respectively. This might be attributed to structural characteristics, varying with different molecular weight distributions. Interestingly, among BPH and its peptide fractions, peptides smaller than 3 kDa were noted to exhibit the strongest DPPH and ABTS radical scavenging activity. More intriguingly, this peptide fraction (<3 kDa) could predominantly prolong the induction period of sunflower oil, which was, respectively increased to 1.31 folds. This may be due to high proportions of hydrophobic amino acids. Unexpectedly, the optimal Fe²⁺ chelating activity was observed in the peptide fraction measuring at 3–10 kDa, showing highly positive correlations with histidine and arginine. These identified peptide fractions derived from black bean protein can therefore be employed for food fortification acting as natural antioxidant alternatives.

Pulse protein processing: The effect of processing choices and enzymatic hydrolysis on ingredient functionality

Plant-based protein ingredients are an emerging solution to the environmental and health issues associated with animal-based proteins. Pulses have become a promising source of these plant-based ingredients. In order to produce functional proteins from pulse grains, extensive processing must be conducted to extract their proteins. These processing steps have consequential effects on the composition and structure of the resulting proteins which may modify their functional properties. This study reviews the most prominent options for each unit operation of pulse protein processing such as extraction, isolation, and drying. It also emphasizes the benefits and drawbacks of such methods and their effects on the pulse protein functionality. Furthermore, enzymatic hydrolysis is discussed as an optional processing step that is thought to counteract loss of functionality associated with pulse protein isolation. However, review of enzymatic hydrolysis literature reveals methodological issues in which insoluble and nonfunctional fractions of pulse protein hydrolysates are removed before analysis. This literature may draw into question the validity of the conventional wisdom that enzymatic hydrolysis is always beneficial to protein functionality.

Physico-chemical properties, antioxidant activity, and ACE inhibitory activity of protein hydrolysates from wild jujube seed

Wild jujube seed protein (WJSP) as one kind of functional food material has attracted much attention due to its highly nutritive and medicinal value in anti-inflammatory and improving immunomodulatory ability. However, owing to its large molecular weight and complex structure, biological activities of WJSP were greatly limited and cannot be fully utilized by the human body. Therefore, how to improve the bioavailability of WJSP and develop promising WJSP nutritious materials is a great challenge. In this work, wild jujube seed protein hydrolysates (WJSPHs) were prepared from WJSP via enzymatic hydrolysis method, and their physico-chemical properties, antioxidant activity, and angiotensin converting enzyme (ACE) inhibitory activity in vitro have been investigated for the first time. SDS-PAGE electrophoresis and size-exclusion chromatographic results indicate that WJSPHs have lower molecular weight distribution (< 5,000 Da) than WJSP. Circular dichroism (CD) spectroscopy and Fourier transform infrared spectroscopy (FTIR) results illustrated that random coil is the main secondary structure of WJSPHs. Antioxidant experiments indicate that WJSPHs exhibit high radicals-scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (94.60%), 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS⁺ ) radicals (90.84%), superoxide radicals (44.77%), and hydroxyl radicals (47.77%). In vitro, WJSPHs can significantly decrease the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), and increase the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in HepG2 cells. Moreover, ACE activity was found that can be significantly inhibited by WJSPHs (73.02%). Therefore, all previously mentioned results suggest that WJSPHs may be a promising antioxidant food to prevent oxidative-related diseases in future. PRACTICAL APPLICATION: This study shows that WJSPHs exhibit high antioxidant activity and ACE inhibitory activity in vitro, which provide potential application value as antioxidant peptides to prevent oxidative-related diseases.

Enzymatic Hydrolysis of Pulse Proteins as a Tool to Improve Techno-Functional Properties

Pulse proteins are being increasingly investigated as nutritious and functional ingredients which could provide alternatives to animal proteins; however, pulse protein ingredients do not always meet the functionality requirements necessary for various applications. Consequently, enzymatic hydrolysis can be employed as a means of improving functional properties such as solubility, emulsifying, foaming, and gelling properties. This review aims to examine the current literature regarding modification of these properties with enzymatic hydrolysis. The effects of enzymatic hydrolysis on the functionality of pulse proteins generally varies considerably based on the enzyme, substrate, processing steps such as heat treatment, degree of hydrolysis, and pH. Differences in protease specificity as well as protein structure allow for a wide variety of peptide mixtures to be generated, with varying hydrophobic and electrostatic properties. Typically, the most significant improvements are seen when the original protein ingredient has poor initial functionality. Solubility is usually improved in the mildly acidic range, which may also correspond with improved foaming and emulsifying properties. More work should be carried out on the potential of enzymatic hydrolysis to modify gelation properties of pulse proteins, as the literature is currently lacking. Overall, careful selection of proteases and control of hydrolysis will be necessary to maximize the potential of enzymatic hydrolysis as a tool to improve pulse protein functionality and broaden the range of potential applications.

Surface tension of native and modified plant seed proteins

The present review, dedicated to Prof. Zbigniew Adamczyk on the occasion of his 70th anniversary, covers the literature data on surface tension and surface compression (dilational) rheology of the adsorbed layers of 21 plant seed proteins (10 leguminous and 11 non-leguminous plants). They are typically analyzed as protein concentrates or isolates, the latter usually obtained by isoelectric precipitation or diafiltration. Despite generally lower solubility, as compared to their animal counterparts (lactoglobulins, caseins, albumins, etc.), the plant seed proteins are also capable of lowering surface tension and forming viscoelastic adsorbed layers. Many seed proteins serve mostly as amino acids reservoirs for the future seedling (storage proteins), hence their instantaneous amphiphilicity is not always sufficient to induce strong adsorption at the aqueous-air interface. They can be, however, conveniently unfolded, hydrolyzed and/or chemically/enzymatically modified to expose more hydrophilic or hydrophobic patches. As shown in numerous contributions reviewed below, the resulting shift of the hydrophilic-lipophilic balance can boost their surface activity to the level comparable to that of many animal proteins or low molecular weight surfactants. An important advantage of the plant seed proteins over the animal ones is their much lower environmental cost and abundance in many plants (e.g. ~40% in sunflower or soybean seeds).

Current Progress in the Extraction, Functional Properties, Interaction with Polyphenols, and Application of Legume Protein

Legume protein can replace animal-derived protein because of its high protein content, low price, lack of cholesterol, complete amino acids, and requirements of vegetarianism. Legume protein has not only superior functional properties but also high biological activities. Therefore, it is widely used in the food industry. However, there are few studies on the comprehensive overview of legume protein. In this review, the extraction, functional properties, interaction with polyphenols, application of legume protein, and activities of their peptides were comprehensively reviewed. Legume proteins are mainly composed of globulin and albumin. The methods of protein extraction from legumes mainly include wet separation (alkali solution and acid precipitation, salt extraction, enzyme extraction, and ultrasonic-assisted extraction) and dry separation (electrostatic separation). Besides, various factors (heat, pH, and concentration) could significantly affect the functional properties of legume protein. Some potential modification technologies could further improve the functionality and quality of these proteins. Moreover, the application of legume protein and the effects of polyphenols on structural properties of legume-derived protein were concluded. Furthermore, the bioactivities of peptides from legume proteins were discussed. To improve the bioactivity, bioavailability, and commercial availability of legume-derived protein and peptides, future studies need to further explore new preparation methods and potential new activities of legume-derived proteins and active peptides. This review provides a real-time reference for further research on the application of legume protein in the food industry. In addition, this review provides a new reference for the development of legume-derived protein functional foods and potential therapeutic agents.

Co-delivery of insulin and quercetin in W/O/W double emulsions stabilized by different hydrophilic emulsifiers

Insulin (hydrophilic) and quercetin (hydrophobic) have broad biological benefits; however, their rapid hydrolysis (via protease degradation) during digestion hinders their stability and delivery for absorption before degrading. In this study, we encapsulated insulin and quercetin using a self-assembled water-in-oil-in-water (W/O/W) double emulsion. We prepared the co-delivery emulsion by two-step emulsification and investigated the effects of the type of hydrophilic emulsifier for the outer water phase on the physicochemical properties, stability, and digestive properties. The black-bean-protein-stabilized W/O/W double emulsion had a higher absolute zeta potential value (52.80 mV), higher encapsulation efficiency (insulin: 95.7%, quercetin: 93.4%), lower viscosity, better emulsifying properties (EAI: 122.26 m²/g, ESI: 224 min), and lower levels of hydroperoxides (0.86 mmol/L) and TBARS (25.80 μmol/L) than emulsions stabilized by other hydrophilic emulsifiers. The emulsion yielded a 2.60- and 4.56-fold increase in the bioaccessibility of insulin and quercetin, respectively, while increasing their chemical stability and solubility under simulated gastrointestinal conditions.

Plant-Derived Antioxidants: Significance in Skin Health and the Ageing Process

Natural substances have traditionally been used in skin care for centuries. There is now an ongoing search for new natural bioactives that not only promote skin health but also protect the skin against various harmful factors, including ultraviolet radiation and free radicals. Free radicals, by disrupting defence and restoration mechanisms, significantly contribute to skin damage and accelerate ageing. Natural compounds present in plants exhibit antioxidant properties and the ability to scavenge free radicals. The increased interest in plant chemistry is linked to the growing interest in plant materials as natural antioxidants. This review focuses on aromatic and medicinal plants as a source of antioxidant substances, such as polyphenols, tocopherols, carotenoids, ascorbic acid, and macromolecules (including polysaccharides and peptides) as well as components of essential oils, and their role in skin health and the ageing process.