Soy Glycinin Research Articles

Microcapsules with condensates and liposomes composite membranes fabricated via soy protein simple coacervation

Coacervation is a common phenomenon in plant proteins which however has yet been well recognized. This study systematically investigated the properties of soy glycinin coacervates, explored the wetting behavior between the condensates and oil droplets in order to obtain microcapsules with core-shell structure, and furthermore figured out the strategy to stabilize the condensate membranes. Fluidity of glycinin coacervates was characterized by viscosity and fluorescence recovery after photo bleaching which was highly dependent on solution parameters and intriguingly increased with prolonged time due to protein structure reorganization. Complete engulfment of oil droplets by coacervates leading to core-shell structure formation was achieved at salinity≥0.1M NaCl and pH ≥ 7 above room temperature. Core-shell structure could be preserved by membranization using liposome coating as it prevented the coalescence between coacervates. Condensate membranes were further hardened by a combination of physical and enzymatic crosslinking using calcium ions and transglutaminase respectively which enabled the microcapsules to survive in the gastric environment. This study is important as it paves way for fabricating well designed microcapsules based on the simple coacervation of plant proteins which are biocompatible and widely abundant.

Soy glycinin-carboxymethyl cellulose “chain bead-like” nanocomplexes: Focus on formation mechanism, functional characteristics and stability properties

In this study, the aim was to solve the problem of poor functional characteristics and stability of soy glycinin (11S). 11S and carboxymethyl cellulose (CMC) nanocomplexes (SCs) were prepared by pH-driven method. They were further analyzed for the effects on the SCs formation mechanism, function and stability properties of CMC concentration (0.05%, 0.1%, 0.5%, 1%, w/v) and degree of substitution (DS, 0.7, 0.9, 1.2). The particle size and zeta potential indicated that the SCs were small in size, uniformly distributed, and high in potential. Classical DLVO theory calculation, FTIR, 3D fluorescence spectroscopy, and UV spectroscopy revealed that 11S and CMC interact mainly through electrostatic forces and hydrogen bonding, and the secondary and tertiary structures of the protein were altered. SEM, AFM and TEM showed that 11S formed “protein nanobeads” and engulfed the “chain” of CMC, generating “chain bead-like” SCs. With the increase in CMC concentration and DS, the hydrophobicity decreased and the molecular flexibility increased of SCs. The solubility, turbidity, emulsifying and foaming properties showed the tendency to enhance and then decrease as the CMC concentration increased; these properties improved better when the DS was stronger. The optimum functional characteristics of the formed SCs were obtained when the concentration and DS of CMC were 0.5% and 1.2, respectively. Furthermore, the addition of CMC significantly improved the pH, ionic stability and thermal stability of the nanocomplexes. This study will provide a theoretical basis for deeper understanding of the mechanism of pH-driven protein-polysaccharide interactions and applications in functional foods.

Effect of Thermal Treatment on Gelling and Emulsifying Properties of Soy β-Conglycinin and Glycinin.

This study investigated the impact of different preheat treatments on the emulsifying and gel textural properties of soy protein with varying 11S/7S ratios. A mixture of 7S and 11S globulins, obtained from defatted soybean meal, was prepared at different ratios. The mixed proteins were subjected to preheating (75 °C, 85 °C, and 95 °C for 5 min) or non-preheating, followed by spray drying or non-spray drying. The solubility of protein mixtures rich in the 7S fraction tended to decrease significantly after heating at 85 °C, while protein mixtures rich in the 11S fraction showed a significant decrease after heating at 95 °C. Surprisingly, the emulsion stability index (ESI) of protein mixtures rich in the 7S fraction significantly improved twofold during processing at 75 °C. This study revealed a negative correlation between the emulsifying ability of soy protein and the 11S/7S ratio. For protein mixtures rich in either the 7S or the 11S fractions, gelling proprieties as well as emulsion activity index (EAI) and ESI showed no significant changes after spray drying; however, surface hydrophobicity was significantly enhanced following heating at 85 °C post-spray drying treatment. These findings provide insights into the alterations in gelling and emulsifying properties during various heating processes, offering great potential for producing soy protein ingredients with enhanced emulsifying ability and gelling property. They also contribute to establishing a theoretical basis for the standardized production of soy protein isolate with specific functional characteristics.

Insight into the interaction and binding mechanism of a natural nonnutritive sweetener mogroside V with soybean protein isolates based on multi-spectroscopic techniques and computational simulations

As a natural low-calorie sweetener, Mogroside V (Mog-V) has gradually become one of the alternatives to sucrose with superior health attributes. However, Mog-V will bring unpleasant aftertastes when exceeding a threshold concentration. To investigate the possibility of soy protein isolates (SPIs), namely β-conglycinin (7S), and glycinin (11S) as flavor-improving agents of Mog-V, the binding mechanism between Mog-V and SPIs was explored through multi-spectroscopy, particle size, zeta potential, and computational simulation. The results of the multi-spectroscopic experiments indicated that Mog-V enhanced the fluorescence of 7S/11S protein in a static mode. The binding affinity of 7S-Mog-V was greater compared with 11S-Mog-V. Particle size and zeta potential analysis revealed that the interaction could promote aggregation of 7S/11S protein with different stability. Furthermore, computational simulations further confirmed that Mog-V could interact with the 7S/11S protein in different ways. This research provides a theoretical foundation for the development and application of SPI to improve the flavor of Mog-V, opening a new avenue for further expanding the market demand for Mog-V.

Comparison and inhibition mechanism study on the in vitro digestibility of rice starch complex with soy β-conglycinin and soy glycinin

To inhibit the digestion of indica rice starch (IRS), an excellent strategy was to add exogenous proteins that interact with IRS, which was closely associated with the protein components. Herein, this study compared the effects of soy protein subfractions, soy β-conglycinin (7S) and soy glycinin (11S), on IRS digestion and explored its inhibition mechanisms. This study used hydrothermal processing to prepare IRS complexes with soy protein subfractions (7S and 11S) at different starch-protein ratios. The results found that adding 7S and 11S exhibited different inhibitory patterns on starch digestion. Compared to IRS, a higher slowly digestible starch (SDS) content (40.91%, p < 0.05) was observed at the IRS-7S ratios of 20:8, while the 20:6 IRS-11S complex showed a higher resistant starch (RS) content (15.76%, p < 0.05). Subsequently, the interactions between IRS and soy protein subfractions and their multi-scale structural changes were explored. The rheological results revealed that hydrophobic interaction and hydrogen bonding were the main driving forces. Various structural changes were closely associated with inhibitory modes of soy protein subfractions on IRS digestion. In detail, the increased SDS content in IRS-7S complexes was attributed to the formation of compact protein physical barriers, aggregated structures with more ordered regions, and flexible secondary conformations of 7S. However, the high-density structures and the stable secondary conformations of 11S were responsible for the increased RS content in IRS-11S complexes. Thus, this study could provide directions for developing SDS-enriched or RS-enriched starch-based products.

Homologous Overexpression of Tyrosinase in Trichoderma reesei and Its Application in Glycinin Cross-Linking.

Tyrosinase is capable of oxidizing tyrosine residues in proteins, leading to intermolecular protein cross-linking, which could modify the protein network of food and improve the texture of food. To obtain the recombinant tyrosinase with microbial cell factory instead of isolation tyrosinase from the mushroom Agaricus bisporus, a TYR expression cassette was constructed in this study. The expression cassette was electroporated into Trichoderma reesei Rut-C30 and integrated into its genome, resulting in a recombinant strain C30-TYR. After induction with microcrystalline cellulose for 7 days, recombinant tyrosinase could be successfully expressed and secreted by C30-TYR, corresponding to approximately 2.16 g/L tyrosinase in shake-flask cultures. The recombinant TYR was purified by ammonium sulfate precipitation and gel filtration, and the biological activity of purified TYR was 45.6 U/mL. The purified TYR could catalyze the cross-linking of glycinin, and the emulsion stability index of TYR-treated glycinin emulsion was increased by 30.6% compared with the untreated one. The cross-linking of soy glycinin by TYR resulted in altered properties of oil-in-water emulsions compared to emulsions stabilized by native glycinin. Therefore, cross-linking with this recombinant tyrosinase is a feasible approach to improve the properties of protein-stabilized emulsions and gels.

Lactic acid bacteria modulate the gastrointestinal digestive behavior of soy glycinin and correlation with its immunoreactivity: a peptidomic study.

Lactic acid bacterial fermentation helps reduce the immunoreactivity of soy protein. Nevertheless, the effect of lactic acid bacterial fermentation on a particular soy allergen and the consequent dynamic change of epitopes during gastrointestinal digestion are unclear. In this study, soy glycinin was isolated and an in vitro dynamic gastrointestinal model was established to investigate the dynamic change in the immunoreactivity and peptide profile of unfermented (UG) and fermented glycinin (FG) digestates. The results demonstrated that the FG intestinal digestate had a lower antigenicity (0.08%-0.12%) and IgE-binding capacity (1.49%-3.61%) towards glycinin at the early (I-5) and middle (I-30) stages of gastrointestinal digestion, especially those prepared at 2% (w/v) protein concentration. Peptidomic analysis showed that the glycinin subunits G1 and G2 were the preferred ones to release the most abundant peptides, whereas G2, G4, and G5 had an elevated epitope-cleavage rate in FG at stages I-5 and I-30. Three-dimensional modeling revealed that fermentation-induced differential degradation epitopes in gastrointestinal digestion were predominantly located in the α-helix and β-sheet structures. They were closely correlated with the reduced immunoreactivity of soy glycinin.

Soybean Antigen Protein-Induced Intestinal Barrier Damage by Trigging Endoplasmic Reticulum Stress and Disordering Gut Microbiota in Weaned Piglets.

Endoplasmic reticulum (ER) stress is a crucial factor in the pathogenesis of intestinal diseases. Soybean antigenic proteins (β-conglycinin and soy glycinin) induce hypersensitivity reactions and intestinal barrier damage. However, whether this damage is associated with ER stress, autophagy, and the gut microbiome is largely unclear. Therefore, in this study, we aimed to investigate the effect of dietary supplementation with soy glycinin (11S glycinin) and β-conglycinin (7S glycinin) on intestinal ER stress, autophagy, and flora in weaned piglets. Thirty healthy 21-day-old weaned "Duroc × Long White × Yorkshire" piglets were randomly divided into three groups and fed a basic, 7S-supplemented, or 11S-supplemented diet for one week. The results indicated that 7S/11S glycinin disrupted growth performance, damaged intestinal barrier integrity, and impaired goblet cell function in piglets (p < 0.05). Moreover, 7S/11S glycinin induced ER stress and blocked autophagic flux in the jejunum (p < 0.05) and increased the relative abundance of pathogenic flora (p < 0.01) and decreased that of beneficial flora (p < 0.05). In conclusion, 7S/11S glycinin induces intestinal ER stress, autophagic flux blockage, microbiota imbalance, and intestinal barrier damage in piglets.

Interfacial behavior and emulsifying property of thermosonication -treated soy glycinin

Thermosonication (TS) is an unconventional processing technique that modifies the structure and aggregation of proteins to improve their functional properties. In this study, we investigated the effect of TS at 40 °C, 60 °C, and 80 °C on the emulsification properties of glycinin (11S). The findings revealed that TS reduced the size of the protein particles while increasing their surface hydrophobicity index to 8177.83. TS treatment improved the stability of the emulsion, increasing the interfacial protein content, apparent viscosity, and emulsion stability, while reducing the adsorption pressure of 11S at the oil–water interface. After TS treatment at 80 °C followed by storage at 4 °C for 21 d, the emulsion turbiscan stability index (TSI) value (2.5) remained stable. By altering the adsorption characteristics of 11S at the oil–water interface, TS can increase the stability of the produced emulsion.

Biomacromolecule assembly of soy glycinin-potato starch complexes: Focus on structure, function, and applications

The effect of the cross-linking mechanism and functional properties of soy glycinin (11S)-potato starch (PS) complexes was investigated in this study. The results showed that the binding effecting and spatial network structure of 11S-PS complexes via heated-induced cross-linking were adjusted by biopolymer ratios. In particular, 11S-PS complexes with the biopolymer ratios of 2:15, had a strongest intermolecular interaction through hydrogen bonds and hydrophobic force. Moreover, 11S-PS complexes at the biopolymer ratios of 2:15 exhibited a finer three-dimensional network structure, which was used as film-forming solution to enhance the barrier performance and mitigate the exposure to the environment. In addition, the 11S-PS complexes coating was effective in moderating the loss of nutrients, thereby extending their storage life in truss tomato preservation experiments. This study provides helpful to insights into the cross-linking mechanism of the 11S-PS complexes and the potential application of food-grade biopolymer composite coatings in food preservation.

Esterified Soy Proteins with Enhanced Antibacterial Properties for the Stabilization of Nano-Emulsions under Acidic Conditions

Soy protein isolate (SPI), including β-conglycinin (7S) and glycinin (11S), generally have low solubility under weakly acidic conditions due to the pH closed to their isoelectric points (pIs), which has limited their application in acidic emulsions. Changing protein pI through modification by esterification could be a feasible way to solve this problem. This study aimed to obtain stable nano-emulsion with antibacterial properties under weakly acidic conditions by changing the pI of soy protein emulsifiers. Herein, the esterified soy protein isolate (MSPI), esterified β-conglycinin (M7S), and esterified glycinin (M11S) proteins were prepared. Then, pI, turbidimetric titration, Fourier transform infrared (FTIR) spectra, intrinsic fluorescence spectra, and emulsifying capacity of esterified protein were discussed. The droplet size, the ζ-potential, the stability, and the antibacterial properties of the esterified protein nano-emulsion were analyzed. The results revealed that the esterified proteins MSPI, M7S, and M11S had pIs, which were measured by ζ-potentials, as pH 10.4, 10.3, and 9.0, respectively, as compared to native proteins. All esterified-protein nano-emulsion samples showed a small mean particle size and good stability under weakly acidic conditions (pH 5.0), which was near the original pI of the soy protein. Moreover, the antibacterial experiments showed that the esterified protein-based nano-emulsion had an inhibitory effect on bacteria at pH 5.0.

Use of oligomeric globulins to efficiently fabricate nanoemulsions: Importance of enhanced structural stability by introducing trehalose

Food-grade nanoemulsions using plant proteins as the sole emulsifier has attracted increasing interest in the food field. However, plant proteins present limitations in emulsification performance owing to their extensive aggregation and unfavorable adsorption behavior, when applied to stabilize emulsions. In the current work, a novel strategy to efficiently form nanoemulsions using plant oligomeric globulins (soy β-conglycinin and glycinin) as the sole emulsifier was proposed through the introduction of trehalose prior to emulsification, in order to overcome the above-mentioned limitations. The formed nanoemulsions were small-sized and well-dispersed, and displayed high stability against flocculation and coalescence. The underlying mechanism for this was largely associated with the enhanced structural stability of protein which contributes to improved interfacial adsorption behavior. Results indicated that the proteins were highly stable during microfluidization and adsorption at the interface in the presence of trehalose. Further research on protein adsorption behavior revealed more rapid diffusion rate, as well as less structural unfolding and rearrangement at oil-water interface of protein particles in trehalose-rich system, than in the trehalose-poor system. Through trehalose coating, oligomeric globulins could perform as outstanding Pickering particles with a strong structural integrity at oil-water interface.

Preparation, characterization, and foaming properties of soy protein nanoparticles by the cross-linking reaction induced by microbial transglutaminase

Native soy proteins have limited surface properties, but fortunately, it is expected that their foaming behaviors can be improved through the enzymatic cross-linking method. In this paper, by using the cross-linking method with microbial transglutaminase (mTG) as the catalyst, soy protein isolate (SPI), soy β-conglycinin (7S), and soy glycinin (11S) nanoparticles (NPs) were prepared in the molten state of the protein induced by dithiothreitol (DTT). We compared the structural characteristics of these nanoparticles, including particle sizes, morphologies, zeta potentials, surface hydrophobicities, changes of spatial structure, and cross-linking degrees. In addition, their foaming properties, including foamabilities, foam stabilities, and bubble diameters, were also tested. The results show that there are no significant differences in the foamabilities between the native soy proteins and their nanoparticles with similar initial foam heights. However, it is found that 11S NPs have enhanced foam stabilities with longer half-lives and smaller changes in bubble size, which is closely related to their high wettability and cross-linking degree. This study may provide references for the application of soy protein nanoparticles as new foam stabilizers to replace the traditional foaming agents in the food industry.

The preparation of soy glycinin/sugar beet pectin complex network gels catalyzed by laccase under weakly acidic conditions.

Traditional soy protein gel products such as tofu, formed from calcium sulfate or magnesium chloride, have poor textural properties and water retention capacity. Soy glycinin (SG) is the main component affecting the gelation of soy protein and can be cross-linked with polysaccharides, such as sugar beet pectin (SBP), and can be modified by changing system factors (e.g., pH) to improve the gel's properties. Soy glycinin/sugar beet pectin (SG/SBP) complex double network gels were prepared under weakly acidic conditions using laccase cross-linking and heat treatment. The structural changes in SG and the properties of complex gels were investigated. Soy glycinin exposed more hydrophobic groups and free sulfhydryl groups at pH5.0. Under the action of laccase cross-linking, SBP could promote the unfolding of SG tertiary structures. The SG/SBP complex gels contained 46.77% β-fold content and had good gelling properties in terms of hardness 290.86 g, adhesiveness 26.87, and springiness 96.70 mm at pH5.0. The T22 relaxation time had the highest peak, and magnetic resonance imaging (MRI) showed that the gel had even water distribution. Scanning electron microscopy (SEM) and confocal scanning laser microscopy (CLSM) indicated that the SG/SBP complex network structure was uniform, and the pore walls were thicker and contained filamentous structures. Soy glycinin/ sugar beet pectin complex network gels have good water-holding, rheological, and textural properties at pH5.0. The properties of soy protein gels can be improved by binding to polysaccharides, with laccase cross-linked, and adjusting the pH of the solution. © 2022 Society of Chemical Industry.

Expression of a Salt-Tolerant Pseudolysin in Yeast for Efficient Protein Hydrolysis under High-Salt Conditions.

Protease biocatalysis in a high-salt environment is very attractive for applications in the detergent industry, the production of diagnostic kits, and traditional food fermentation. However, high-salt conditions can reduce protease activity or even inactivate enzymes. Herein, in order to explore new protease sources, we expressed a salt-tolerant pseudolysin of Pseudomonas aeruginosa SWJSS3 isolated from deep-sea mud in Saccharomyces cerevisiae. After optimizing the concentration of ion cofactors in yeast peptone dextrose (YPD) medium, the proteolytic activity in the supernatant was 2.41 times more than that in the control group when supplemented with 5 mM CaCl2 and 0.4 mM ZnCl2. The extracellular proteolytic activity of pseudolysin reached 258.95 U/mL with optimized expression cassettes. In addition, the S. cerevisiae expression system increased the salt tolerance of pseudolysin to sodium chloride (NaCl)and sodium dodecyl sulfate (SDS) and the recombinant pseudolysin retained 15.19% activity when stored in 3 M NaCl for 7 days. The recombinant pseudolysin was able to efficiently degrade the β-conglycinin from low-denatured soy protein isolates and glycinin from high-denatured soy protein isolates under high temperatures (60 °C) and high-salt (3 M NaCl) conditions. Our study provides a salt-tolerant recombinant protease with promising applications in protein hydrolysis under high-salt conditions.

Preparation of SP/Lysozyme Composite Gel and the Inhibition of Staphylococcus aureus

Soy glycinin (SG) and sugar beet pectin (SBP) were cross-linked using laccase to form a complex SG/SBP (SP) and then combined with lysozyme under the heating condition to form SP/lysozyme composite gels. The properties of SP/lysozyme composite gel and its inhibition on Staphylococcus aureus were investigated. Results revealed that the zeta potential changed from −32 to 8.2 mV upon adding lysozyme, its morphology was larger, and the particle size and turbidity increased. The Fourier transform infrared spectroscopy and X-ray diffraction results indicated that the interactions between SP and lysozyme were electrostatic interaction and hydrogen bonding. The mechanical properties showed that the SP/lysozyme composite gel could recover its original shape after 90% strain compression when SP/lysozyme was 10:4 and 10:5, and the storage modulus (G′) was higher at 10:5 about 105 Pa. Scanning electron microscopy results showed that the granular size increased, and the antibacterial property on S. aureus was enhanced.

Effect of the double heating cycle on the thermal gelling properties of vicilin fractions from soy, mung bean, red bean and their mixture with soy glycinin

This study investigated the effect of a double heating cycle (90 °C) on the thermal gelling behavior of fractionated vicilins from soybean (SV), mung bean (MV) and red bean (RV) with and without soy glycinin (SG). Both MV and RV consisted of peptides with relatively low Mw comparing to those of SV. Differential scanning calorimetry (DSC) indicated that MV and RV had a greater thermal stability than those of SV. Based on oscillatory shear rheometry, the first heating could not cause the gelation of MV and RV, but the thermal gel of both vicilins could be formed by the second heating stage. The stiffness of the RV gel was lower than that of MV. Based on texture profile analysis (TPA), the hardness and springiness of gel prepared by MV did not differ from those of SV, whereas RV gel showed high cohesiveness but low hardness and springiness compared to that of SV (p < 0.05). The gumminess of MV and RV gels was lower than that of SV gel (p < 0.05). The differences in TPA parameters between MV and RV were mainly due to different contributions of hydrophobic and electrostatic interactions, which also affected their microstructures. However, their gel characteristics disappeared when SG was mixed with these vicilins. The results indicated that both MV and RV had a potential to regulate the textural properties of soy protein-based gel matrix, and double heating was necessary to form a viscoelastic thermal gel containing vicilin fractions.

Interactions between Mannosylerythritol Lipid-A and Heat-Induced Soy Glycinin Aggregates: Physical and Chemical Characteristics, Functional Properties, and Structural Effects.

Protein-surfactant interactions have a significant influence on food functionality, which has attracted increasing attention. Herein, the effect of glycolipid mannosylerythritol lipid-A (MEL-A) on the heat-induced soy glycinin (11S) aggregates was investigated by measuring the structure, binding properties, interfacial behaviors, and emulsification characteristics of the aggregates. The results showed that MEL-A led to a decrease in the surface tension, viscoelasticity, and foaming ability of the 11S aggregates. In addition, MEL-A with a concentration above critical micelle concentration (CMC) reduced the random aggregation of 11S protein after heat treatment, thus facilitating the formation of self-assembling core-shell particles composed of a core of 11S aggregates covered by MEL-A shells. Infrared spectroscopy, circular dichroism spectroscopy, fluorescence spectroscopy, and isothermal titration calorimetry also confirmed that the interaction forces between MEL-A and 11S were driven by hydrophobic interactions between the exposed hydrophobic groups of the protein and the fatty acid chains or acetyl groups of MEL-A, as well as the hydrogen bonding between mannosyl-D-erythritol groups of MEL-A and amino acids of 11S. The findings of this study indicated that such molecular interactions are responsible for the change in surface behavior and the enhancement of foaming stability and emulsifying property of 11S aggregates upon heat treatment.

A soy glycinin derived octapeptide protects against MCD diet induced non-alcoholic fatty liver disease in mice

Soy glycinin derived octapeptide (SGP8) is a peptide obtained from degradation of the soy glycinin, whose amino acid sequence is IAVPGEVA. To determine the effect of SGP8 on non-alcoholic fatty liver disease (NAFLD), steatosis HepG2 cells were induced by 1 mmol/L free fatty acid (FFA) and C57BL/6J mice were fed with methionine-choline deficient (MCD) diet for 3 weeks to establish NAFLD model. The results of oil red O staining and total cholesterol (TC)/triglyceride (TG) contents showed that SGP8 could significantly reduce the lipid content of steatosis HepG2 cells. In vivo, SGP8 lowered plasma alanine aminotransferase (ALT) and low density lipoprotein (LDL) content, normalized hepatic superoxide dismutase (SOD) and malondialdehyde (MDA) production, and reduced the severity of liver inflammation. The results of Western blotting showed that SGP8 increased expression of Sirtuin-1 (SIRT1) and phosphorylation level of AMP activated protein kinase (AMPK) in hepatocytes. Through activation of SIRT1/AMPK pathway, SGP8 downregulated the expression of sterol regulatory element binding protein 1c (SREBP-1c) and its target genes ACC and FAS expression levels, and increased the phosphorylation level of acetyl CoA carboxylase (ACC). Furthermore, SGP8 also upregulated the expression of transcription factor peroxisome proliferator activated receptor α (PPARα), which was regulated by SIRT1/AMPK pathway, and its target gene CPT1 level. In conclusion, SGP8 might improve NAFLD by activating the SIRT1/AMPK pathway. Our data suggest that SGP8 may act as a novel and potent therapeutic agent against NAFLD.

An insight into the changes in conformation and emulsifying properties of soy β-conglycinin and glycinin as affected by EGCG: Multi-spectral analysis

The binding mechanisms between soy β-conglycinin/glycinin and (−)-epigallocatechin-3-gallate (EGCG) were evaluated using multi-spectral techniques and molecular modeling. Additionally, the emulsifying properties of β-conglycinin/glycinin were investigated in their interactions with EGCG. Fluorescence analysis revealed that the quenching of β-conglycinin/glycinin by EGCG was static quenching. Specifically, EGCG to β-conglycinin/glycinin resulted in the conformation changes of the Trp and Tyr residues, around which the polarity toward more hydrophilic. The dominated binding between β-conglycinin and EGCG was hydrogen bonding, whereas was mainly hydrophobic force between glycinin and EGCG. Such affinity induced a more organized protein confirmation with decreased random coil and increased α-helix and β-structures. The docking data indicated the better affinity between glycinin and EGCG, compared to β-conglycinin. The emulsifying ability and capacity of β-conglycinin were enhanced with involvement EGCG, however no effect was found for glycinin. Our findings deliver insights in understanding of the interaction mechanisms between β-conglycinin/glycinin and EGCG.