Protein-polyphenol Complexes Research Articles

Interaction between pea protein isolate and quercetin: Effects on protein conformation and quercetin activity.

Comprehensive comprehension of the interaction between proteins and polyphenols is crucial for advancing their utilization in food processing. This study investigated no-covalent interaction between pea protein isolate (PPI) and quercetin (Que) through spectroscopic analysis and molecular simulation. Fourier transform infrared spectroscopy and circular dichroism spectrum showed that the interaction between PPI and Que changed the secondary structure of the protein due to a decrease in α-helix content and an increase in the random coil. Thermodynamic parameters indicated that the Quebound PPI via hydrogen bonds and hydrophobic interactions (ΔH>0, ΔS>0, and ΔG<0), which was also confirmed by molecular docking. Particle size and ζ-potential showed that PPI and Que demonstrated effective interaction and binding capabilities, enhancing the stability. In addition, the antioxidant and bioaccessibility of complexes have also been enhanced. This study shed a light on the application of protein-polyphenol complexes for developing functional foods. PRACTICAL APPLICATION: Interaction between pea protein isolate and quercetin can change the protein conformation to maintain the stability of quercetin and is helpful to expand the market value and application value of plant protein. The research has important implications for using leguminous protein as embedded support to improve the stability of polyphenols compounds.

Application of soy protein isolate-naringenin complexes as fat replacers in low-fat cream: Based on protein conformational changes, aggregation states and interfacial adsorption behavior

In this study, changes in the structural and functional properties of soybean protein isolate (SPI)-naringenin (NG) complexes under different amounts of naringenin treatments were explored, elucidating the effect of the complexes as fat replacers at the 15 % substitution level on the properties of low-fat cream. Finally, the correlation between the structure and function of the complex and the properties of low-fat cream was further analyzed. The addition of NG promotes the increase of SPI aggregation and particle size, and reduces the interfacial tension of the complex. Meanwhile, at the mass ratio of 48:3, NG and SPI formed a dendritic network structure suitable for stabilizing cream. The fat properties of cream indicate that low-fat creams stabilized by appropriate proportions of SPI-NG complexes displayed small and dense fat crystal network structures. In addition, low-fat cream stabilized by the SPI-NG complexes have improved whipping time, overrun, firmness, storage stability and rheological properties compared to natural SPI. It is worth noting that the overall quality of the cream stabilized by the SPI-NG complex with a mass ratio of 48:3 was almost close to that of full-fat cream. Therefore, this study promotes the potential applications of protein-polyphenol complexes as fat replacers in the food industry.

Characterization and emulsification of BSA/theaflavins complexes

Complex interactions occurring between proteins and polyphenols can impact the structural and functional properties of proteins, thereby enhancing their potential applications in food. We here used bovine serum albumin (BSA) as a prototypical protein for examining the structural and functional properties of the complex formed using theaflavins/BSA (BSA/TFs) in varying ratios. Additionally, the stability and rheological properties of the complex were analyzed as an emulsifier in high internal phase emulsions (HIPEs). According to the findings, the non-covalent bonding of TFs with BSA primarily involves hydrogen bonding, which changes BSA's secondary structure, including a reduction in α-helix and an increase in β-sheet. Additionally, BSA/TFs exhibited low interfacial tension, thereby forming a highly efficient adsorbent layer on the oil–water interface and improving the stability of the emulsion film. HIPEs stabilized using BSA/TFs as an emulsifier have good storage stability and rheological properties. The particle size of d(4, 3) after 30 days of storage was 19 μm. Regarding rheological properties, the elastic modulus was larger than the viscous modulus, which indicated the gel characteristics of the complex. The structural recovery degree was greater than 1, which demonstrated the anti-thixotropy and superior emulsification effect. This study provides a theoretical foundation and experimental direction regarding the implementation of protein–polyphenol complexes for augmenting food quality and functionality.

Characterization of ultrasound-assisted covalent binding interaction between β-lactoglobulin and dicaffeoylquinic acid: Great potential for the curcumin delivery

The low bioavailability and poor gastrointestinal instability of curcumin hampers its application in pharmaceutical and food industries. Thus, it is essential to explore efficient carrier (e.g. a combination of polyphenols and proteins) for food systems. In this study, covalent β-lactoglobulin (LG)-dicaffeoylquinic acids (DCQAs) complexes were prepared by combining ultrasound and free radical induction methods. Covalent interactions between LG and DCQAs were confirmed by analyzing reactive groups. Variations in secondary or tertiary structure and potential binding sites of covalent complexes were explored using Fourier transform infrared spectroscopy and circular dichroism. Results showed that the β-sheet content decreased and the unordered content increased significantly (P < 0.05). The embedding rate of curcumin in prepared LG-DCQAs complexes using ultrasound could reach 49 % − 62 %, proving that complexes could embed curcumin effectively. This study highlights the benefit of ultrasound application in fabrication of protein–polyphenol complexes for delivering curcumin.

High internal phase emulsions stabilized by pea protein isolate-EGCG-Fe3+ complexes: Encapsulation of β-carotene

Protein complexes have great potential for forming and stabilizing high internal phase emulsions (HIPEs) loaded with bioactive compounds. In this study, we investigated the potential of three types of complexes, namely pea protein isolate (PPI), PPI-epigallocatechin gallate (EGCG) and PPI-EGCG-Fe3+, to form and stabilize HIPEs with a 75% oil phase volume fraction. Initially, the impact of pH and emulsifier type on emulsions performance was investigated. Confocal laser scanning microscopy (CLSM) and particle size analysis showed that all three complexes could form HIPEs that remained stable under acidic and neutral conditions. These emulsions contained uniform oil droplets coated by a layer of the complexes. Notably, the PPI-EGCG-Fe3+ complexes formed HIPEs with the highest thermal and storage stability, which was attributed to the denser and thicker interfacial coatings. These emulsions also protected encapsulated β-carotene from degradation when exposed to light and thermal stress conditions. Furthermore, we measured lipid digestion and β-carotene bioaccessibility in the emulsions using an in vitro digestion model. The PPI-EGCG-Fe3+ stabilized emulsions not only exhibited slow fatty acid release but also enhanced β-carotene bioaccessibility (46.5%) under simulated small intestine conditions. This study demonstrates the potential of using protein-polyphenol-Fe3+ complexes to form and stabilize HIPEs, which may then be used to enhance the bioaccessibility and bioactivity of hydrophobic nutraceuticals.

Synergistic modification of structural and functional characteristics of whey protein isolate by soybean isoflavones non-covalent binding and succinylation treatment: A focus on emulsion stability

This investigation explored the structural and functional characteristics of whey protein isolate (WPI) and succinylated whey protein isolate (SAn-WPI) modified by varying concentrations (0.25, 0.5, 1.0, 2.0 mg/mL) of soybean isoflavones (SI) through non-covalent interactions. The results of SDS-PAGE and total phenolic contents confirmed the formation of non-covalent complexes. Molecular docking techniques, Fourier-transform infrared spectroscopy, and thermodynamic parameters obtained from fluorescence spectra revealed that non-covalent binding to SI primarily occurs through hydrophobic interactions and hydrogen bonding. Additionally, multispectroscopic techniques demonstrated that succinylation treatment resulted in partial unfolding of the proteins. This led to increased protein flexibility, exposing more binding sites and facilitating the binding between the proteins and SI. Therefore, SAn-WPI/SI exhibits stronger fluorescence quenching ability, antioxidant activity, and emulsifying property compared to WPI/SI at the same SI concentration. The findings illustrate the synergistic effect of non-covalent binding to SI and succinylation treatment on the WPI molecules, thereby promoting the utilization of protein-polyphenol complexes in food emulsion systems.

Production and utilization of non-covalent dairy-based proteins complexed with date palm leave polyphenols for improving curcumin stability

This study provides insights into the non-covalent complexation of greent solvent extracted date leaf polyphenolic extracts (DLPE) with bovine and camel dairy proteins and their utilization for enhancing the photo and thermal stabilities of curcumin loaded into nano-emulsion. UV–Vis and fluorescence spectroscopies showed marked variation among bovine and camel dairy-DLPE complexes. Dairy protein-DLPE complexation improved the radical scavenging activities compared to unmodified milk proteins. Caseins-DLPE complexes showed higher total phenolic content (TPC) than whey-DLPE complexes with camel casein (CC) showing highest values. The formation of protein-polyphenol complexes was also predicted using molecular docking that suggested van der Waals interaction as a dominant force binding camel dairy protein with DLPE. Further, curcumin-loaded nanoemulsions were fabricated using dairy proteins-DLPE complexes as emulsifiers. The thermal stability of curcumin loaded in nanoemulsions was studied at different temperatures (55 °C, 75 °C and 95 °C) for varying periods of time (0–6 h) while photostability was studied by exposure to UV light for a period of 120 min. The results showed that the thermal and photostability of curcumin improved when dairy protein-DLPE complexes were used for nanoemulsion production. Camel casein-DLPE stabilized nanoemulsions imparted the highest thermal and photostabilities to curcumin while camel whey-DLPE showed the lowest retention of curcumin in nanoemulsions. In vitro digestion showed complexation of caseins with DLPE improved the bioaccesibility of curcumin. Moreover, curcumin bioaccesibility was higher for CC-DLPE (69.25%) compared to CC (49.83%) stabilized emulsions. Overall, CC-DLPE complexes demonstrated the superior performance for stabilizing the emulsion and delivering the curcumin in simulated GI tract efficiently.

Investigation of bovine β-lactoglobulin-procyanidin complexes interactions and its utilization in O/W emulsion

Procyanidins are bioactive polyphenols that have a strong affinity to proteins. Beta-lactoglobulin (BLG) is widely used as an emulsifier in the food and other industries. This study evaluated the interaction between BLG and A-type procyanidin dimer (PA2) using the spectroscopic, thermodynamic, and molecular simulation. PA2 decreased the transmissivity and quenched the intrinsic fluorescence of BLG, suggesting that the two molecules formed a complex. The binding of PA2 reduced the surface hydrophobicity and altered the conformation of BLG with increasing the random coil regions. Thermodynamic and isothermal titration calorimetry analyses suggested that the main driving force of PA2-BLG interaction was hydrophobic attraction. Molecular docking simulations were used to identify the main interaction sites and forces in the BLG-PA2 complexes, which again indicated that hydrophobic interactions dominated. In addition, the influence of PA2 on the ability of BLG to form and stabilize O/W emulsions was analyzed. Emulsions formulated using BLG-PA2 complexes contained relatively small droplets (D4,3 ≈ 0.7 μm) and high surface potentials (absolute value >50 mV). Compared to BLG alone, BLG-PA2 complexes improved the storage stability of the emulsions. This study provides valuable new insights into the formation, properties, and application of protein-polyphenol complexes as functional ingredients in foods.

Soy protein isolate-catechin non-covalent and covalent complexes: Focus on structure, aggregation, stability and in vitro digestion characteristics

Studies on soybean protein–polyphenol complexes mainly focus on the effects of non-covalent/covalent interactions on the structure and function of the complexes, and there are few studies on the stability and in vitro digestion mechanism of these complexes. We investigated the effects of non-covalent/covalent binding of catechin with soy protein isolate (SPI) on the structure, aggregation, stability and digestive characteristics of the SPI-Catechin complexes. SPI-Catechin non-covalent/covalent complexes were prepared under neutral (pH 7.0) or alkaline (pH 9.0) conditions, and the protein:polyphenol ratio was optimized. The interaction of SPI and catechin disordered the secondary structure and exposed more hydrophobic residues to a hydrophilic microenvironment. SPI-Catechin covalent complexes exhibited higher thermal stability, storage stability, and antioxidant activity compared to non-covalent complexes. Results of in vitro digestion showed that SPI-Catechin covalent complexes can substantially (up to ∼86%) improve the bioaccessibility of catechin. The stronger anti-digestion ability of the covalent complex might be due to the more complete structure of 7S and 11S subunits in the digestion products. This study provides a theoretical basis for the application of SPI-Catechin non-covalent/covalent complexes as functional components of plant protein drinks. • The degree of binding between catechin and SPI was affected by the ratio and pH value. • SPI-Catechin covalent complexes were more stable than non-covalent complexes. • Non-covalent/covalent binding of SPI improved the bioaccessibility of catechin. • SPI-Catechin covalent complexes had stronger anti-digestive ability.

Myofibrillar protein-chlorogenic acid complexes ameliorate glucose metabolism via modulating gut microbiota in a type 2 diabetic rat model

Growing evidence suggests that polyphenols could mitigate type 2 diabetes mellitus (T2DM). The glucose-regulatory effects of protein-bound polyphenols, however, have been rarely studied. In this study, macrogenomic and metabolomic analyses were applied to investigate the modulation of myofibrillar protein-chlorogenic acid (MP-CGA) complexes on T2DM rats from the gut microbiota perspective. Results showed that MP-CGA improved hyperglycemia and hyperlipidemia, decreased intestinal inflammation, and reduced intestinal barrier injury. MP-CGA reconstructed gut microbiota in T2DM rats, elevating the abundance of probiotics Bacteroides, Akkermansia, and Parabacteroides while suppressing opportunistic pathogens Enterococcus and Staphylococcus. MP-CGA significantly elevated the concentrations of intestinal metabolites like butyric acid that positively regulate T2DM and reduced the secondary bile acids contents. Therefore, MP-CGA modulated the gut microbiota and related metabolites to maintain stable blood glucose in T2DM rats, providing new insights into the application of protein-polyphenol complexes in foods.

Study of soybean protein isolate-tannic acid non-covalent complexes by multi-spectroscopic analysis, molecular docking, and interfacial adsorption kinetics

In this study, non-covalent complexes of soybean protein isolate (SPI) and tannic acid (TA) were prepared, and the interaction mechanism between SPI and TA was investigated by multiple methods of multi-spectroscopy and molecular docking techniques. The non-covalent binding to TA resulted in a reduction of the α-helix and β-sheet contents and a decrease in the fluorescence intensity. The fluorescence-quenching mechanism and molecular docking analysis determined that TA statically quenched the fluorescence of SPI with a binding constant of 1168 L/mol, a binding site number of 0.99, ΔG < 0, ΔH of −32.666 kJ/mol, and ΔS of −0.0466 kJ/mol, and the interaction between SPI and TA was dominated by hydrogen bonding. The interfacial adsorption kinetics study revealed that the maximum diffusion rate of the SPI-TA complex was 0.06771, which occurred at 1.0 mg/mL of TA. The emulsification activity index and emulsion stability index of the complexes under these conditions were 98 m2/g and 48.3 min, respectively. The above findings help to elucidate the mechanism of non-covalent binding of SPI with TA and promote the application of protein-polyphenol complexes in emulsions.

Investigating the role of tartaric acid in wine astringency

Previous studies acknowledged that tartaric acid-imparted low-pH contributed to the enhancement of astringency, but in-depth studies are lacking and the underlying mechanisms are not clearly understood. This work introduced new insight into the effect of tartaric acid on astringency perception from the perspectives of complex formation, protein secondary structure, chemical bond type and salivary layer fluidity by establishing models using proteins (α-amylase, salivary proteins) and tannic acid. Results demonstrated that tartaric acid affects wine astringency by two mechanisms: a) Tartaric acid compound directly affects the wine astringency by forming ternary complexes and causing the protein structure to stretch by changing the hydrogen bond and hydrophobic bond between protein–polyphenol complexes. b) pH affected astringency by increasing the fluidity of the salivary layer rather than increasing the consumption of the salivary layer. The findings provide valuable information to the wine industry to regulate wine astringency by the management of tartaric acid.

Comparison of soy protein isolate-(–)-epigallocatechin gallate complexes prepared by mixing, chemical polymerization, and ultrasound treatment

The effects of the preparation method (mixing, chemical polymerization, or ultrasound treatment) on the structure and functional properties of soy protein isolate-(–)-epigallocatechin-3-gallate (SPI-EGCG) complexes were examined. The mixing treated SPI-EGCG samples (M−SE) were non-covalently linked, while the chemical polymerization and ultrasound treated SPI-EGCG samples (C-SE and U-SE, respectively) were bound covalently. The covalent binding of EGCG with protein improved the molecular weight and changed the structures of the SPI by decreasing the α-helix content. Moreover, U-SE samples had the lowest particle size (188.70 ± 33.40 nm), the highest zeta potential (−27.82 ± 0.53 mV), and the highest polyphenol binding rate (59.84 ± 2.34 %) compared with mixing and chemical polymerization-treated samples. Furthermore, adding EGCG enhanced the antioxidant activity of SPI and U-SE revealed the highest DPPH (84.84 ± 1.34 %) and ABTS (88.89 ± 1.23 %) values. In conclusion, the SPI-EGCG complexes prepared by ultrasound formed a more stable composite system with stronger antioxidant capacity, indicating that ultrasound technology may have potential applications in the preparation of protein-polyphenol complexes.

Molecular interaction mechanism and structure–activity relationships of protein–polyphenol complexes revealed by side-directed spin labeling-electron paramagnetic resonance (SDSL-EPR) spectroscopy

Deciphering interactions between bioactive protein and polyphenols are critical for designing and controlling functional protein–polyphenol complexes. Herein, using the site-directed spin labeled T4 lysozyme (T4L) and rosmarinic acid (RA) as a model system, we combined electron paramagnetic resonance spectra to investigate molecular interaction mechanism of the protein–polyphenol complexes in structural or conformational details. Experimental results show that molecular interactions between T4L and RA are a process from order to disorder. TEM images display that the complexes finally assemble into quasi-spherical colloidal particles. When T4L/RA ratio is 1:1, the complexes exhibit the optimized enzymatic and antioxidant dual-functionalities due to the synergetic effect and protection mechanism. However, with excess addition of RA, the enzymatic and antioxidant activities of the complexes started to attenuate because the catalytic active site and bioactive hydroxyl groups were buried. The revealed high-resolution interaction process could help better understand the corresponding alterations between structure and functionalities.

Structural Characterization and Evaluation of Interfacial Properties of Pea Protein Isolate-EGCG Molecular Complexes.

Highlights Pea protein isolate (PPI) and EGCG spontaneously formed complexes.Protein–polyphenol complexation was mainly driven by hydrogen bonding.The binding of EGCG influenced the structure and functionality of PPI.PPI-EGCG complexes had better emulsifier properties than PPI. There is increasing interest in using plant-derived proteins in foods and beverages for environmental, health, and ethical reasons. However, the inherent physicochemical properties and functional performance of many plant proteins limit their widespread application. Here, we prepared pea protein isolate (PPI) dispersions using a combined pH-shift/heat treatment method, and then, prepared PPI-epigallocatechin-3-gallate (EGCG) complexes under neutral conditions. Spectroscopy, calorimetry, molecular docking, and light scattering analysis demonstrated that the molecular complexes formed spontaneously. This was primarily ascribed to hydrogen bonds and van der Waals forces. The complexation of EGCG caused changes in the secondary structure of PPI, including the reduction in the α-helix and increase in the β-sheet and disordered regions. These changes slightly decreased the thermal stability of the protein. With the accretion of EGCG, the hydrophilicity of the complexes increased significantly, which improved the functional attributes of the protein. Optimization of the PPI-to-EGCG ratio led to the complexes having better foaming and emulsifying properties than the protein alone. This study could broaden the utilization of pea proteins as functional ingredients in foods. Moreover, protein–polyphenol complexes can be used as multifunctional ingredients, such as antioxidants or nutraceutical emulsifiers.

Insights into the Interaction between Polyphenols and β-Lactoglobulin through Molecular Docking, MD Simulation, and QM/MM Approaches

In this work, we have explored the interaction of three different polyphenols with the food protein β-lactoglobulin. Antioxidant activities of polyphenols are influenced by complexation with the protein. However, studies have shown that polyphenols after complexation with the protein can be more beneficial due to enhanced antioxidant activities. We have carried out molecular docking, molecular dynamics (MD) simulation, and quantum mechanics/molecular mechanics (QM/MM) studies on the three different protein–polyphenol complexes. We have found from molecular docking studies that apigenin binds in the internal cavity, luteolin binds at the mouth of the cavity, and eriodictyol binds outside the cavity of the protein. Docking studies have also provided binding free energy and inhibition constant values that showed that eriodictyol and apigenin exhibit better binding interactions with the protein than luteolin. For eriodictyol and luteolin, van der Waals, hydrophobic, and hydrogen bonding interactions are the main interacting forces, whereas for apigenin, hydrophobic and van der Waals interactions play major roles. We have calculated the root mean square deviation (RMSD), root mean square fluctuations (RMSF), solvent-accessible surface area (SASA), interaction energies, and hydrogen bonds of the protein–polyphenol complexes. Results show that the protein–eriodictyol complex is more stable than the other complexes. We have performed ONIOM calculations to study the antioxidant properties of the polyphenols. We have found that apigenin and luteolin act as better antioxidants than eriodictyol does on complexation with the protein, which is consistent with the results obtained from MD simulations.

Interactions between the protein-epigallocatechin gallate complex and nanocrystalline cellulose: A systematic study

In this work, the noncovalent interactions between the protein-epigallocatechin gallate (protein-EGCG) complex and nanocrystalline cellulose (NCC) were systematically investigated. Rheological properties, including large amplitude oscillation shear (LAOS), transient rheology, and conventional rheology of the mixture were also evaluated. As obtained, flexible myofibrillar protein-epigallocatechin gallate (MP-EGCG) and rigid ovalbumin-epigallocatechin gallate (Ova-EGCG) follow different rules in the stability of the regulatory system because of the difference in noncovalent interactions, triggering different rheological responses of the complexes. Additionally, MP-EGCG/NCC showed an obvious strain overshoot during LAOS flow, which could not be obtained in Ova-EGCG/NCC. Notably, the fibrous MP-EGCG network was the factor that dominated the formation of a more stable suspension system with strong hydrogen bonding, dipole–dipole interactions and/or van der Waals forces. This study can provide some ideas for the future study of the interaction between protein–polyphenol complexes and polysaccharides.

Dynamic high‐pressure microfluidization enhanced the emulsifying properties of wheat gliadin by rutin

Dynamic high-pressure microfluidization (DHPM) has attracted increasing interest in food macromolecule modification, which has been used in the preparation of nanoemulsions, gel-like soy protein emulsions, and nanocelluloses. This study explored the effects of DHPM under 0, 40, 80, 120, and 160 MPa with the addition of rutin on the physical, structural, rheological, and morphological characteristics of wheat gliadin. Infrared spectrum analysis showed that the DHPM treatment resulted in the structural changes of wheat gliadin and the primary interactions between wheat gliadin and rutin were hydrogen bond and hydrophobic effects. Here, 120 MPa DHPM treatment with the addition of rutin caused decreased particle sizes but increased zeta-potential and viscoelastic properties of wheat gliadin, with particle sizes at 245.20 nm and zeta-potential at 21.76 mV, respectively. The results showed that the combination of DHPM treatment at 120 MPa and rutin to wheat gliadin exhibited the morphology of nanospheres with a more compact structure, uniform particle distribution, and fine emulsifying properties. Practical applications The interaction between protein and polyphenol are able to preserve the stability of the functional compounds, allow targeted and controlled release, improve texture in the food industry. Improvement of functional characteristics of protein-polyphenol complexes with high emulsifying stability during food processing is crucial to use in the food industry. Therefore, the goal of this research is to use a soluble complex of gliadin-rutin for the development of its functional characteristics.

Improving foam performance using colloidal protein–polyphenol complexes: Lactoferrin and tannic acid

In this study, colloidal complexes were prepared from bovine lactoferrin (BLF) and tannic acid (TA) and then their ability to form and stabilize foams was characterized. The molecular interactions between BLF and TA were studied using fluorescence and molecular docking analysis, which suggested that hydrophobic forces were primarily involved in holding the complexes together. The production of colloidal BLF-TA complexes was supported by increases in turbidity and mean particle diameter, quenching of intrinsic fluorescence, decrease in surface hydrophobicity, and change in conformation. When used alone, BLF exhibited good foam formation but poor foam stability properties. In contrast, BLF-TA complexes exhibited good foam stability but poor foamability properties. The change in foaming properties of the proteins was closely related to their interactions with the polyphenols. These findings may be useful for the development of novel functional ingredients to construct food foams with good physicochemical and nutritional attributes.

Effect of simultaneous treatment combining ultrasonication and rutin on gliadin in the formation of nanoparticles.

Proteins, one of the vital nutritional compounds sensitive to the environment, can be modified by interaction with polyphenols. Ultrasonication has been applied for enhancing the functional properties of proteins. In this study, the interactions of gliadin (G) and rutin (R) in the absence and presence of ultrasonication (0, 150, 300, 450, and 600 W) for 20 min were investigated, with a focus on the properties of emulsions prepared by G-R complexes. Ultrasonication improved the interaction, which increased the content of β-type secondary structure. Ultrasonication at 450 W increased the particle size of the conjugates. For Pickering emulsions, treating the covering of R on G with ultrasonication improves the stability of the G-based emulsion significantly, owing to the strong films formed on the oil-water interfaces. The G-R complexes treated at 450 W ultrasonication formed emulsions that showed higher potential and storage modulus (G') and denser microstructures than those of the untreated emulsions. Nevertheless, ultrasound treatment at 600 W weakened the emulsion properties that were stabilized by the conjugates. Ultrasound combined R was shown to be a potential processing technology for changing the protein structure and producing stable emulsions. PRACTICAL APPLICATION: The interactions between proteins and polyphenols are able to preserve the stability of the functional compounds, allow targeted and controlled release, and improve the texture of these complexes employed in the food industry. Improvements in the functional characteristics of the protein-polyphenol complexes so that they possess high emulsifying stability during food processing is a crucial factor for employing them in the food industry. Therefore, the aim of this research is using a soluble complex of gliadin-rutin for the development of its functional characteristics.