Effects of conjugated interactions between Perilla seed meal proteins and different polyphenols on the structural and functional properties of proteins

Controlled hydrolysis and EGCG conjugation enhance the ADH/ALDH activation activity of chia seed meal protein hydrolysates: Fabrication and structural characterization

This study examines the effects of hydrolysis duration (20-100 min using flavourzyme) and EGCG conjugation on the structure and bioactivity of chia seed meal protein hydrolysates (CSPH) through multi-spectroscopic techniques and physicochemical property evaluation. Subsequently, the activation effects of EGCG-conjugated peptides on alcohol metabolism-related enzymes were further analyzed through the integration of peptidomics, bioinformatics, and computational chemistry. It was found that with the extension of hydrolysis time, the thermal stability of CSPH diminishes, its rigid structure becomes more flexible, and its crystallinity decreases (by up to 27.19 %). Meanwhile, the activation effects on alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity were significantly enhanced (P < 0.05). CSPH hydrolyzed for 60 min demonstrated the highest binding affinity for EGCG, primarily driven by hydrophobic interactions and hydrogen bonds. The CSPH-EGCG conjugate exhibited enhanced physicochemical properties and significantly elevated activation of ADH and ALDH, with ADH activation rising from 22.66 % to 95.56 % and ALDH activation from 9.45 % to 30.93 %, compared to unmodified CSPH. Seven active peptides were identified from PE-60 by peptidomics and bioinformatics. Computer docking optimized selected three optimal peptides (IPW, FPIH, and IYP). Two-dimensional and three-dimensional interaction analyses showed that these peptides bind to EGCG, ADH, and ALDH via hydrogen bonds, hydrophobic interactions, and salt bridges. These findings highlight the potential of controlled hydrolysis with flavourzyme and EGCG incorporation to enhance CSPH's properties and bioactivities and offer insights into the practical applications of CSPH and its EGCG complexes in food processing and therapeutic systems.

Tannic acid-mediated covalent effects on the structural and antioxidant properties of dual zein/casein protein complex nanoparticles

Protein-polyphenol conjugates with enhanced antioxidant properties offer significant benefits to multiple food systems, including emulsions, gels, and food packaging systems. In this study, tannic acid (TA)-covalently mediated ternary zein/casein-tannic acid nanoparticles (ZCTPs) were effectively fabricated using a pH-driven method. Results showed that the addition of TA reduced the particle size of ZCTPs (from 93 to 74 nm), with improved uniformities (PDI of 0.25) and greater stabilities (zeta potential of -48 mV) compared to zein/casein nanoparticles (ZCPs). Further, SDS-PAGE confirmed the successful establishment of covalent binding between TA and dual proteins. In ZCTPs, TA exhibited a high affinity (66-93 %) to proteins, obviously inducing rearrangements in the protein secondary and tertiary structures. Afterward, the antioxidant activities of ZCTPs were significantly enhanced to 57 and 79 % against DPPH· and ABTS+·, respectively. This novel protein-polyphenol conjugate holds promising potential as a functional ingredient and delivery system in the food industry.

Covalent conjugation of hemp protein isolates with curcumin via ultrasound to improve its structural and functional properties

This study investigated the covalent conjugation of hemp protein isolate (HPI) with curcumin induced by ultrasound-generated free radicals and its impact on HPI's structural and functional properties. Ultrasound treatment unfolded the protein structure, increased free amino and sulfhydryl groups, and altered the secondary structure. Curcumin addition enhanced free radical scavenging capacity. Conjugation with curcumin significantly improved emulsifying activity index (+ 2.6-fold), foam stability (+ 1.8-fold), and solubility (+ 0.9-fold) and further enhanced free radical scavenging capability (+ 2.4 or 2.7-fold). Conjugation with curcumin also enabled gel formation, as evidenced by a continuous increase in the storage modulus of HPI during heating and cooling. These findings highlight the potential of HPI-curcumin conjugates as healthy ingredients in functional food applications.

Sea buckthorn polyphenols on gastrointestinal health and the interactions with gut microbiota

The potential health benefits of sea buckthorn polyphenols (SBP) have been extensively studied, attracting increasing attention from researchers. This paper reviews the composition of SBP, the effects of processing on SBP, its interactions with nutrients, and its protective role in the gastrointestinal tract. Polyphenols influence nutrient absorption and metabolism by regulating the intestinal flora, thereby enhancing bioavailability, protecting the gastrointestinal tract, and altering nutrient structures. Additionally, polyphenols exhibit anti-inflammatory and immunomodulatory effects, promoting intestinal health. The interaction between polyphenols and intestinal flora plays a significant role in gastrointestinal health, supporting the composition and diversity of the gut microbiota. However, further research is needed to emphasize the importance of human trials and to explore the intricate relationship between SBP and gut microbiota, as these insights are crucial for understanding the mechanisms underlying SBP's benefits for the gastrointestinal tract (GIT).

Improved emulsifying and foaming properties of ovalbumin and antioxidant activity of (-)-gallocatechin gallate: Effects of ultrasound-assisted glycation based on natural deep eutectic solvents and noncovalent binding

In this study, ultrasound-assisted glycated ovalbumin (G-UOVA) based on natural deep eutectic solvents (NADES) was prepared using response surface optimization. The binding affinity of (-)-gallocatechin gallate (GCG) to native OVA (NOVA), ultrasound treated OVA (UOVA), glycated OVA (GOVA), and G-UOVA followed G-UOVA > GOVA > UOVA > NOVA. The effects of various modifications and GCG binding on the secondary structure, particle size, and thermal stability of NOVA were investigated. After ultrasound-assisted glycation, the emulsifying activity, emulsifying stability, foaming activity, and foaming stability of NOVA increased by 61.9 %, 119.0 %, 36.0 %, and 47.1 %, respectively, and further increased due to GCG binding. The encapsulation of native and modified OVA, particularly G-UOVA, significantly enhanced the antioxidant activity and bioaccessibility of GCG. The degradation of GCG encapsulated by G-UOVA decreased from 100 % to 20.9 % within 10 h. This study can lay the foundation for further applications of NADES in related fields.

Functional, structural, and rheological properties of the complexes containing sunflower petal extract with dairy and plant-based proteins

This study aims to investigate the impact of sunflower petal extract (SFE) on the functional and structural properties of sodium caseinate and chickpea proteins. For this purpose, 3.5 % of sodium caseinate solution and 3.5 % of protein extracted from chickpea powder were prepared in phosphate buffer (pH = 7). SFE was used at different concentrations, from 1 to 3 % in different protein solutions and functional, structural and rheological properties were measured. The results revealed that complexation of SFE with different proteins can enhance the antioxidant, foaming properties, solubility, emulsion activity, emulsion stability, viscoelastic behavior, and can decrease surface hydrophobicity. FTIR and docking results showed that the most bonding type was non-covalent bonds. Major phenolic compounds containing heliannone A, B, and kaempferol had strong affinity with sodium caseinate, and then chickpea protein. Therefore, the results demonstrated that SFE and its complexes had appropriate emulsifying properties that reduces interfacial tension in the water/oil interface.

Preparation of bovine liver peptide-flavonoids binary complexes by free radical grafting: Rheological properties, functional effects and spectroscopic studies

Free radical grafting is a green and fast method for modification of proteins and bioactive peptides. In this study, different flavonoids with flavonol, flavonoid glycoside and flavan-3-ol structures, such as quercetin (QC), rutin (RUT), and catechin (C), which are commonly used in food applications, were used as the research objects, and the binary systems of bioactive bovine liver peptides complexed with the flavonoids were prepared by free radical grafting method. The findings indicated that the affinity of catechin for bovine liver peptides markedly exceeded that of both quercetin and rutin. This observation was consistent with the extent of reduction in the content of free amino. The emulsion system formed using the binary complex was homogeneous and dense under optical microscopy, with reduced droplet diameters and significantly improved interfacial properties such as shear resistance. The combination of bovine liver peptides and flavonoids can be regarded as an effective means of modification.

Effects of catechins with different structure characteristics on the structure and properties of gluten-catechin covalent complex

Effects of catechins with different structure characteristics on the structure and properties of gluten-catechin covalent complex were investigated, and the structure-activity relationship was further explored. Catechins including epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epigallocatechin-3-gallate (EGCG) could successfully covalently bind with gluten through C-N and/or C-S bonds. The physicochemical properties of covalent complex, including particle size, thermal stability, content of free amino groups, free sulfhydryl groups and disulfide bonds, were significantly affected by different catechins, and the action order was: EGCG > ECG > EGC > EC. Multispectral analysis indicated that catechins significantly changed the tertiary and secondary structures of covalent complex, while galloylated catechins (ECG and EGCG) showed stronger capability than non-galloylated catechins (EC and EGC). Furthermore, the in vitro protein digestibility of covalent complexes reduced with all catechins, and its polyphenols release rate and antioxidant activity were improved. Combining multispectral analysis and molecular dynamics simulation, the hydroxyl group at 5th position in B ring and the galloyl group at 3rd position in C ring played an important role to affect the covalent binding of catechins and gluten, while the amount of hydroxyl groups and the molecule size of catechins both significantly affected its capability to covalently bind with gluten.

Hydrodynamic cavitation induced fabrication of soy protein isolate-polyphenol complexes: Structural and functional properties

The combination of polyphenols and protein can improve the functional characteristics of protein. How to effectively promote the binding of polyphenols to protein is still a difficult topic. In this study, hydrodynamic cavitation (HC) was used to induce the fabrication of complexes between soy protein isolate (SPI) and different polyphenols (tannic acid (TA), chlorogenic acid (CGA), ferulic acid (FA), caffeic acid (CA), and gallic acid (GA)). The effect of HC on the interaction between polyphenols and SPI was investigated, and the structural and functional properties of the formed complexes were characterized. The results showed that HC treatment led to SPI structure stretching, which increased the binding level of polyphenols, especially that of TA (increased from 35.08 ± 0.73% to 66.42 ± 1.35%). The increase in ultraviolet-visible absorption intensity and quenching of fluorescence intensity confirmed that HC enhanced the interaction between polyphenols and protein. HC treatment reduced the contents of free sulfhydryl and amino groups in SPI-polyphenol complexes and altered their Fourier transform infrared spectroscopy, indicating that HC treatment promoted the formation of C-N and C-S bonds between SPI and polyphenols. Circular dichroism spectroscopy indicated that HC treatment altered the secondary structure of SPI-polyphenol complexes, inducing an increase in α-helix and random coil contents and a decrease in β-sheet content. Regarding functional properties, HC treatment improved the emulsification and antioxidant activity of SPI-polyphenol complexes. Therefore, HC is an effective technique for promoting the binding of polyphenols to protein.

Comprehensive Review of Biological Functions and Therapeutic Potential of Perilla Seed Meal Proteins and Peptides

This comprehensive review explores the biological functions of Perilla frutescens seed proteins and peptides, highlighting their significant potential for health and therapeutic applications. This review delves into the mechanisms through which perilla peptides combat oxidative stress and protect cells from oxidative damage, encompassing free radical scavenging, metal chelating, in vivo antioxidant, and cytoprotective activities. Perilla peptides exhibit robust anti-aging properties by activating the Nrf2 pathway, enhancing cellular antioxidant capacity, and supporting skin health through the promotion of keratinocyte growth, maintenance of collagen integrity, and reduction in senescent cells. Additionally, they demonstrate antidiabetic activity by inhibiting α-amylase and α-glucosidase. The cardioprotective effects of perilla peptides are underscored by ACE-inhibitory activities and combat oxidative stress through enhanced antioxidant defenses. Further, perilla peptides contribute to improved gut health by enhancing beneficial gut flora and reinforcing intestinal barriers. In liver, kidney, and testicular health, they reduce oxidative stress and apoptotic damage while normalizing electrolyte levels and protecting against cyclophosphamide-induced reproductive and endocrine disruptions by restoring hormone synthesis. Promising anticancer potential is also demonstrated by perilla peptides through the inhibition of key cancer cell lines, alongside their anti-inflammatory and immunomodulating activities. Their anti-fatigue effects enhance exercise performance and muscle function, while perilla seed peptide nanoparticles show potential for targeted drug delivery. The diverse applications of perilla peptides support their potential as functional food additives and therapeutic agents.

Synergistic effects of phosphorylation modification and protocatechuic acid copolymerization improve the physical and oxidation stability of high internal phase emulsion stabilized by perilla protein isolate

A compact antioxidant interfacial layer was fabricated by combining phosphorylation treatment with protocatechuic acid (PA) copolymerization to enhance the physical and oxidative stability of high internal phase emulsions (HIPEs) prepared using perilla protein isolate (PPI). The covalent binding between PPI and phosphate groups induced conformational changes, facilitating the interaction between PPI and PA. The formed phosphorylated PPI-PA conjugates (LPPI-PA) exhibited a reduced particle size of 196.75 nm, promoting their adsorption at the interface. HIPEs prepared by LPPI-PA conjugates showed higher storage stability due to decreased droplet size, increased interfacial protein adsorption content (90.48%), and the formation of an interconnected network within the system. Additionally, the combination of LPPI and PA anchored PA to the interface, significantly inhibiting lipid oxidation in HIPEs as evidenced by low levels of lipid hydroperoxide (30.33 μmol/g oil) and malondialdehyde (379.34 nmol/g oil). This study holds significant implications for improving the stability of HIPEs.

The Effect of Hydrodynamic Cavitation on the Structural and Functional Properties of Soy Protein Isolate-Lignan/Stilbene Polyphenol Conjugates

In this study, hydrodynamic cavitation technology was utilized to prepare conjugates of soy protein isolate (SPI) with polyphenols, including resveratrol (RA) and polydatin (PD) from the stilbene category, as well as arctiin (AC) and magnolol (MN) from the lignan category. To investigate the effects of hydrodynamic cavitation treatment on the interactions between SPI and these polyphenols, the polyphenol binding capacity with SPI was measured and the changes in the exposed sulfhydryl and free amino contents were analyzed. Various methods, including ultraviolet-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy, were also used to characterize the structural properties of the SPI-polyphenol conjugates. The results showed that compared to untreated SPI, SPI treated with hydrodynamic cavitation exposed more active groups, facilitating a greater binding capacity with the polyphenols. After the hydrodynamic cavitation treatment, the ultraviolet-visible absorption of the SPI-polyphenol conjugates increased while the fluorescence intensity decreased. Additionally, the content of exposed sulfhydryl and free amino groups declined, and changes in the secondary structure were observed, characterized by an increase in the α-helix and random coil content accompanied by a decrease in the β-sheet and β-turn content. Furthermore, the SPI-polyphenol conjugates treated with hydrodynamic cavitation demonstrated improved emulsifying characteristics and antioxidant activity. As a result, hydrodynamic cavitation could be identified as an innovative technique for the preparation of protein-phenolic conjugates.

Perilla Seed Oil and Protein: Composition, Health Benefits, and Potential Applications in Functional Foods

Perilla (Perilla frutescens) seeds are emerging as a valuable resource for functional foods and medicines owing to their rich oil and protein content with diverse nutritional and health benefits. Perilla seed oil (PSO) possesses a high level of a-linolenic acid (ALA), a favorable ratio of unsaturated to saturated fatty acids, and other active ingredients such as tocopherols and phytosterols, which contribute to its antioxidant, anti-inflammatory, and cardiovascular protective effects. The balanced amino acid ratio and good functional properties of perilla seed protein make it suitable for a variety of food applications. The chemical composition, health benefits, and potential applications of PSO as well as the structural characterization, functional properties, modification methods, bioactivities, and application scenarios of perilla seed protein are comprehensively presented in this paper. Furthermore, the challenges as well as future prospects and research focus of PSO and perilla seed protein are discussed. The growing interest in plant-based diets and functional foods has made PSO and perilla seed protein promising ingredients for the development of novel foods and health products. The purpose of this paper is to highlight implications for future research and development utilizing these two untapped resources to improve human health and nutrition.

Establishing a novel covalent complex of wheat gluten with tea polyphenols: Structure, digestion, and action mechanism

Plant-based proteins represent a more sustainable alternative, the approaches to modify and enhance their functionality and application are focused on. Covalent interaction could significantly modify the structure and function properties of protein. This study investigated the effects of covalent interaction between wheat gluten and tea polyphenols on the structure, aggregation, stability, and digestive properties of their covalent complex, as well as the possible action mechanism. The results showed that tea polyphenols could interact with gluten via covalent bonds (CN and/or CS), while tea polyphenols also acted as a bridge connecting gluten molecules, thus making covalent complex to show the larger particle sizes. This covalent interaction significantly changed the secondary structure, tertiary structure, and surface hydrophobicity of gluten. Moreover, covalent complex exhibited the high polyphenols bioaccessibility during in vitro digestion. The peptide bonds of covalent complex were mainly broken in gastric digestion, while the covalent bonds between tea polyphenols and gluten were completely destroyed in intestinal digestion. In addition, their digestates exhibited excellent antioxidant capability. All results suggest that wheat gluten have potential to prepare functional carrier for transporting active compounds and protecting them during digestion.

Application of resveratrol on oxidative stability of protein-based Antarctic krill oil high internal phase emulsion

Antarctic krill oil (KO) is known for its poor oxidative stability, especially in emulsion systems. In this experiment, a complex of scallop water-soluble protein-resveratrol (SWPs-RES) was mixed with KO to create high internal phase emulsions (HIPEs) with varying RES ratios. The addition of RES led to noticeable conformational changes in SWPs, including fluorescence bursts, alterations in secondary structure, and modifications in binding motifs. The SWPs-RES complex (1:0.2) demonstrated the most effective free radical scavenging activities (HO: 38.61%, DPPH: 72.49%, ABTS: 85.66%), while the SWPs-RES complex (1:0.025) exhibited the highest emulsifying capacity. Furthermore, HIPEs containing the SWPs-RES complex (1:0.2) displayed improved rheological properties, physical stability, and enhanced oxidative stability against lipid oxidation during storage and simulated in vitro digestion. This study lays a scientific foundation for the utilization of scallop protein and Antarctic krill oil in the food industry.

Incorporation of microencapsulated polyphenols from jabuticaba peel (Plinia spp.) into a dairy drink: stability, in vitro bioaccessibility, and glycemic response

This work incorporated bioactives extracted from jabuticaba peel in the form of concentrated extract (JBE) and microencapsulated powders with maltodextrin (MDP) and gum arabic (GAP) in a dairy drink, evaluating its stability, in vitro bioaccessibility, and glycemic response. We evaluated the pH, acidity, colorimetry, total phenolics and anthocyanins, antioxidant capacity, degradation kinetics and half-life of anthocyanins, bioaccessibility, and postprandial glycemic physicochemical characteristics response in healthy individuals. The drinks incorporated with polyphenols (JBE, GAP, and MDP) and the control dairy drink (CDD) maintained stable pH and acidity over 28 days. In color, the parameter a*, the most relevant to the study, was reduced for all formulations due to degradation of anthocyanins. Phenolic and antioxidant content remained constant. In bioaccessibility, we found that after the gastrointestinal simulation, there was a decrease in phenolics and anthocyanins in all formulations. In the glycemic response, we observed that the smallest incremental areas of glucose were obtained for GAP and JBE compared to CDD, demonstrating that polyphenols reduced glucose absorption. Then, the bioactives from jabuticaba peel, incorporated into a dairy drink, showed good storage stability and improved the product's functional aspects.

Simultaneous ultrasound and microwave application in myosin-chlorogenic acid conjugation: Unlocking enhanced emulsion stability

This study investigated the grafting chlorogenic acid (CA) onto myosin, utilizing various techniques including conventional method, ultrasound, microwave, and combination of ultrasound and microwave (UM). The grafting efficiency was as follows: conventional method < microwave < ultrasound < UM. The UM technique manifested the highest CA-binding capacity (80.26 μmol/g myosin) through covalent bonding, and a much shorter time was required for conjugation than conventional method. The conjugation of polyphenol significantly increased the solubility of myosin with reduced aggregation behavior, which was accompanied by structural alterations from ordered structures (α-helix and β-sheet) to disordered forms. The emulsion stabilized by UM-myosin-CA conjugate exhibited the most homogeneous microstructure with favorable creaming stability. Moreover, the resulting emulsion presented strong oxidation resistance and storage stability. These results illustrate the promising potential of employing CA-grafted myosin, especially when processed using the UM technique, in the development of highly efficient emulsifiers.