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Tazeddinova, D., Toshev, A. D., Abylgazinova, A., Rahman, M., Matin, M., Bin Bakri, M. K., and Ayan, O. (2022). "A review of polyphenol and whey protein-based conjugates," BioResources 17(4), 6997-7030.

Abstract

Proteins act as a primary food component obtained from different food sources. In contrast, polyphenols are metabolites and are abundantly present in plants, so their combination plays a crucial role in defining the functional properties of a food product. In the current review, the protein-polyphenol interactions have been briefly reviewed, along with the changes that occur because of their interaction. The mechanisms and the factors affecting the functionalities of the protein-polyphenol conjugates, e.g., the solubility, antioxidant, and gelling properties, have also been briefly reviewed. In addition, the interaction of polyphenols with whey proteins was been reviewed with various applications within the food industry, e.g., emulsifiers, foaming agents, and antioxidants. To end the review, future challenges were also highlighted.


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A Review of Polyphenol and Whey Protein-based Conjugates

Diana Tazeddinova,a Abduvali Djaraovich Toshev,a Aizhan Abylgazinova,b Md. Rezaur Rahman,*,c Md. Mahbubul Matin,d Muhammad Khusairy Bin Bakri,c and Orazov Ayan e

Proteins act as a primary food component obtained from different food sources. In contrast, polyphenols are metabolites and are abundantly present in plants, so their combination plays a crucial role in defining the functional properties of a food product. In the current review, the protein-polyphenol interactions have been briefly reviewed, along with the changes that occur because of their interaction. The mechanisms and the factors affecting the functionalities of the protein-polyphenol conjugates, e.g., the solubility, antioxidant, and gelling properties, have also been briefly reviewed. In addition, the interaction of polyphenols with whey proteins was been reviewed with various applications within the food industry, e.g., emulsifiers, foaming agents, and antioxidants. To end the review, future challenges were also highlighted.

DOI: 10.15376/biores.17.4.Tazeddinova1

Keywords: Protein; Polyphenols; Whey protein; Functional properties; Conjugates; Interactions

Contact information: a: Department of Technology and Catering Organization, South Ural State University, Chelyabinsk 454080 Russian Federation; b: Zhangir Khan Agrarian Technical University, Uralsk Kazakhstan; c: Faculty of Engineering, Universiti Malaysia Sarawak, Jalan Datuk Mohammad Musa, Kota Samarahan, Sarawak, Malaysia; Composite Materials and Engineering Centre, Department of Civil and Environmental Engineering, Washington State University, Pullman 99164 WA USA; d: Department of Chemistry, University of Chittagong; e: Zhangir Khan West Kazakhstan Agrarian – Technical University, Uralsk, Kazakhstan

* Corresponding author: Md Rezaur Rahman, Email: rmrezaur@unimas.my

INTRODUCTION

With more than 8000 different compounds, phenolic compounds are secondary metabolites with the same structure, i.e., an aromatic ring bonded to a hydroxyl group, and they are classified according to their number of carbon atoms (Kroll et al. 2003). Some examples of phenolic compounds are as follows: phenolic acids, flavonoids, lignans, and stilbenes in plants, which can react with protein molecules and undergo chemical change during food processing and even after consumption, as shown in Figs. 1a and 1b (Parada and Aguilera 2007; Crozier et al. 2009). The important factors determining polyphenol-protein interactions include the structural flexibility, molecular weight of the polyphenol, the side chain type, and the hydroxyl group number, as polyphenols with a higher molecular weight and abundant hydroxyl groups have greater protein affinity (Frazier et al. 2010; Xiao et al. 2011; Czubinki and Dwiecki 2017; Buitimea-Cantú et al. 2018). Protein-polyphenol interaction is classified into covalent interactions (irreversible) and noncovalent interactions (reversible), which are further reported as five groups, including electrostatic interactions, hydrogen bonds, pi (π) bonds, hydrophobic interactions, and van der Waals (Prigent et al. 2003; Frazier et al. 2010; Rawel and Rohn 2010; McRae and Kennedy 2011).

Fig. 1a. Major phenolic acid structures

Fig. 1b. Major flavonoid compounds

 

Hydrolysis causes modification to the functional properties of proteins. However, moderate hydrolysis of whey proteins increases their heat stability as a result of the reduced secondary structure. This development does not always translate directly to more complex systems such as emulsions made using hydrolyzed whey protein, where heat stability has been shown to be adversely affected by hydrolysis of whey protein. Conjugation of proteins with polyphenol reaction has been shown to be effective in altering protein functionality (Liu et al. 2012; Costa et al. 2021). Widespread research supporting the beneficial effects of protein modification through conjugation is available in the scientific literature; improved functional properties of proteins including solubility, emulsification, encapsulation, emulsion stability, and thermal stability as a result of conjugation are well documented (Akhtar and Dickinson 2003; Buamard and Benjakul 2017, 2018).

A protein can interact through hydrophobic interactions with polyphenols. Hydrogen bonds and hydrophobic interaction are the primary noncovalent interactions regulating protein-polyphenolic interactions and involved amino acids. Examples include valine, leucine, isoleucine, alanine, phenylalanine, methionine, tryptophan, glycine, cysteine, and tyrosine. Phenolic compounds form a hydrogen bond with the protein carboxyl group, as they are hydrogen donors, so a hydrogen bond is ultimately formed between the oxygen/nitrogen molecule of amino acids and a phenolic hydroxyl group (Prigent et al. 2003; Rawel and Rohn 2010; Xiao et al. 2011; Mulaudizi et al. 2012; Jongberg et al. 2015; Tang et al 2021; Xiong and Guo 2021). The mechanism of the protein-polyphenol reaction is illustrated in Fig. 2. Phenolic compounds can produce a quinone radical via covalent bond formation, and in the presence of oxygen and an alkaline environment, a quinone radical is generated via enzymatic/non-enzymatic reactions (Jongberg et al. 2015; Czajkowska–González et al. 2021; Zhao et al. 2021). In the second step, a quinone forms a dimer via a condensation reaction, known as tannins (which are brown-colored, with a high molecular weight), by reacting with the polypeptide amino acid chain via covalent bonding, and are re-oxidized and react with another polypeptide chain in the third step (Felton et al. 1989; Arts et al. 2001; Buchner et al. 2006). Examples of covalent and noncovalent protein-polyphenol interactions are explained in Table 1 (Fig. 3 and Fig. 4).

Fig. 2. Phenolic acid compound reactions with polypeptide amino acid side chains

Fig. 3. Protein-polyphenol noncovalent conjugation and cross-linking of proteins via hydrogen bonding (a); hydrophobic-hydrophobic interaction (b); and ionic interaction (c)

Fig. 4. Protein-polyphenol covalent conjugation and cross-linking of protein via alkaline (a); and enzymatic (b) reactions

FACTORS AFFECTING THE INTERACTIONS BETWEEN PROTEINS AND PHENOLIC COMPOUNDS

Many factors affect protein-polyphenol reactions, including environmental factors, e.g., pH, temperature, salt concentration, and chemical presence. In addition, the protein type and phenolic compound structures are two important factors (Kroll et al. 2003; Ozdal et al. 2013; Czubinski and Dwiecki 2016) and are strongly influenced by the amino acid sequence, isoelectric point, and hydrophobicity (Frazier et al. 2006; Ali 2016). The higher molecular weight of protein has a higher binding affinity for phenolics, and protein size also plays a vital role in the binding affinity for proanthocyanidin (Siebert 1999; Dubeau et al. 2010). Phenolic compounds are different in terms of their hydroxylation degree, molecular weight, glycosylation, methylation, and hydrogenation. Temperature, an important factor that influences phenolic binding abilities for proteins, e.g., 5-O-caffeoylquinic acid, has a decreased affinity for bovine serum albumin (BSA) and sunflower seed at a higher temperature, primarily because of hydrogen bonding (Prigent et al. 2003; Guo and Xiong 2021; Guo et al. 2021). Another factor is pH, since additional protein-polyphenol precipitation was seen at the protein isoelectric point because of their lower solubility, showing that the optimum pH is near the isoelectric point, which varies for different proteins (Naczk et al. 1996, 2006; Groth et al. 2021). The isoelectric point of a protein is defined as the pH at which the net charge of a protein molecule is zero. Proteins are positively charged at a pH below their isoelectric point and negatively charged at a pH above their isoelectric point. The protein isoelectric point varies greatly from extremely acidic to highly alkaline values ranging from about 4.0 to 12.0. Moreover, isoelectric point values have long been used to distinguish between proteins in methods for protein isolation, separation, purification, crystallization, etc. (Tokamkov et al. 2021). Other influencing factors include the salt type, as a high salt concentration causes oligomeric protein dissociation, which causes a reduction in binding ability (Kanakis et al. 2011).

Various protein functional properties, e.g., emulsification, solubility, antioxidative ability, foaming ability, color, flavor, elasticity, and binding properties, could affect the quality and the sensory food property where the protein function could be affected by the phenolic compound (Abdelfatah 2013; Korpela et al. 2022). The protein-phenolic covalent interactions (Table 1, Fig. 4) could increase the gel network formation, including better mechanical strength and increased thermal stability, and modified proteins could be used as emulsifiers in foods to reduce the emulsion stability and increase the oil droplet size (Aewsiri et al. 2009). Based on the conjugates under typical conditions, it is concluded that foods properties will be affected by wide range of pH. Therefore, it might be useful for physiological saline solution.

Effects on Nutritional Properties

The nutritional value of proteins depends on various factors, e.g., the amino acid composition, protein source, essential amino acids ratio, processing environment, and hydrolysis sensitivity during digestion, but it has been reported that protein digestibility and nutritional value are decreased by phenolic interactions (Rubanza et al. 2005; Abdelfatah 2013). Milk protein interactions with caffeic acid while heating caused a reduction in the availability of thiol groups and lysine, which is related to the presence of quinones via caffeic acid oxidation and the formation of an amino acid complex (Kroll et al. 2003). Soy protein interactions with gallic acid/caffeic acid/chlorogenic acid/quercetin cause a reduction in lysine, tryptophan, and cysteine contents. The condensed tannins, which are present in sorghum, are responsible for reduced digestibility of the sorghum protein (Emmambux and Taylor 2003).

Protein-Polyphenol Conjugates

Promising alternative methods for the modified biomolecule synthesis of a novel compound with the desired physicochemical properties are conjugation, polymerization, or grafting; such approaches are used for yielding improved properties, e.g., sensorial and nutritional, with specific applications (Czubinski and Dwiecki 2016). Protein is present in eggs, meat, cereals, milk, legumes, and oilseed, with diversified amino acid sequences and compositions, making them different in terms of protein function, structure, and conformation (Ozdal et al. 2013). Protein is a major component, with different functions as well as allowing a different compound to be more effective in its role as an anti-oxidant and is widely applicable in the biomedical and pharmaceutical industries (Phillips and Williams 2011; Liu et al. 2015).

Table 2. Protein-Polyphenol Conjugation Changes and Methods in their Function

Phenolic compounds are natural antioxidants with an aromatic ring attached to hydroxyl groups, which prevents or delays oxidative losses. Some of the attained properties via protein-polyphenol conjugation are antimicrobial, antioxidant, and bacterial enzyme inhibition as well as decreasing the oxidative damage level in living cells, DNA, protein, carbohydrates, and lipids (Maqsood et al. 2012; Liu et al. 2017). The protein-polyphenol interaction improves the quality of food, and a non-polar polyphenol-protein conjugate improves the surface hydrophobicity and protein emulsification. Protein-polyphenol conjugates are covalently formed via enzymatic (polyphenol oxidase, laccase, tyrosinase, etc.) or non-enzymatic (alkaline reaction or free-radical grafting) methods (Gu et al. 2017; Liu et al. 2017) (as shown in Table 2).

FACTORS AFFECTING THE FORMATION OF PROTEIN POLYPHENOL CONJUGATES

The two types of factors influencing protein-polyphenol conjugates include extrinsic factors (temperature and pH) and intrinsic factors (polyphenol/protein type and structure), which determine the covalent/noncovalent interactions (Ozdal et al. 2013; Czubinski and Dwiecki 2017). The two major effects that affect the protein-polyphenol interaction are temperature and pH. Temperature affects the protein-polyphenol interaction via hydrogen bonding or hydrophobic-hydrophobic interactions, as heat changes the protein conformation, exposing hydrophobic sites, which influences the hydrophobic compounds to bind (Kulmyrzaev et al. 2005). The hydrophobic effect between curcumin and casein has been observed, and the interaction of caffeic acid with tyrosine, lysine, and tryptophan residues was observed with ionic/hydrogen bonding at a temperature between 10 to 45 °C; as the temperature was increased to 40 to 90 °C, the binding tendency of bovine serum albumin (BSA) to polyphenols decreased (Bonomi et al. 1988; Suryaprakash et al. 2000; Rawel et al. 2005). The amount of hydrogen binding of neochlorogenic acid with sunflower seed protein rapidly decreased as the temperature increased from 30 to 55 °C, as heating at a particular temperature causes the exposure of binding sites via denaturation and conformational changes (Bourvellec and Renard 2012; Ozdal et al. 2013). Covalent interactions between proteins and polyphenols can be induced by heat, as polyphenol oxidation occurs, which results in quinone formation. In addition, at an alkaline pH, polyphenols oxidize to quinones, which covalently react with proteins, showing that the pH influences the protein and polyphenol structure and conformation (Rawel et al. 2005; Ozdal et al. 2014).

APPLICATIONS OF PROTEIN-POLYPHENOL CONJUGATES

Protein-based Films

Protein-based films are of great interest in terms of developing food packing materials, as they have renewable, biodegradable, and eco-friendly properties; however, they have lesser water vapor barrier properties, as they are a hydrophilic type of matrix (Prodpran et al. 2012; Nagarajan et al. 2015). Many hydrophobic substances, e.g., oil and fats, are added to the film-forming solution, and their incorporation overcomes oxidation, producing discoloration and off-odor to overcome this problem (Prodpran et al. 2012). Myofibrillar and legume proteins are soluble in an alkaline environment, and polyphenol is added, so their oxidation occurs, and a protein-polyphenol conjugate is formed (Kaewprachu et al. 2017). Plant extracts can be incorporated in protein films as an antioxidant (Adilah et al. 2018). The addition of a catechin-Bradon extract conjugate not only enhances the antioxidant properties but also the antimicrobial activity of fish myofibrillar film. In addition, soy protein isolate film and fish gelatin are enhanced when conjugated with mango kernel, as they show better antioxidant activity and tensile strength (Kaewprachu et al. 2017; Adilah et al. 2018). The conjugation of EGCG and fish skin gelatin was found to enhance its antioxidant properties and tensile strength and the water vapor barriers and gelatin film packing of chicken skin oil with EGCG decreased lipid oxidation in storage compared to polyethylene packing, so these packings are advised for oil and fat storage (Nilsuwan et al. 2019).

Emulsions

Protein-polyphenol conjugates, having enhanced emulsifying and antioxidative abilities, are used to improve food emulsion stability, e.g., a catechin-ovalbumin conjugate enhances the emulsion stability fish oil, which was produced by free-radical grafting, and the modified emulsions had better storage stability, lower lipid oxidation, and smaller droplet size (Feng et al. 2018). The modified protein surface hydrophobicity improved the emulsifying activity and the conjugated droplets repulsion improved the emulsion stability, as a WPI-EGCG conjugate prevented fish oil deterioration and prevented fish oil lipolysis (Liu et al. 2016a,b; Fan et al. 2018a,b). The oxidized tannic acid-gelatin conjugate stabilized menhaden oil-in-water emulsion and showed less phase separation and lipid oxidation compared to unmodified gelatin and a fish oil emulsion had better oxidative stability with the presence of a B-lactoglobulin-green tea polyphenol conjugate, having the same droplet size (Aewsiri et al. 2009; Von Staszewski et al. 2011). The oil-water emulsion was physically stabilized by a rice hull phenolic extract-rice bran protein hydrolysate conjugate, which made a rapeseed oil emulsion less flocculated and coalescence with a smaller oil droplet size (Cheetangdee and Benjakul 2017; Li et al. 2019). Additionally, many covalent polyphenol-protein conjugates, e.g., a-lactalbumin-catechin, lactoferrin-chlorogenic acid, β-lactoglobulin-catechin, catechin-egg albumin protein, and lactoferrin-EGCG, are used as antioxidants in an oil-in-water emulsion (Yin et al. 2014; Yi et al. 2015). Protein-polyphenol conjugates with enhanced interfacial properties can be absorbed on the oil surface and make the oil droplets stable from electrostatic repulsion and steric hindrance, as shown by milk proteins (Staszewski et al. 2012). Therefore, protein-polyphenol conjugates could be used as antioxidant emulsifiers in food products.

Protein Gels

Protein gel is formed by a three-dimensional protein chain network connected via covalent/noncovalent interaction and can be produced by different methods, e.g., environmental changes, mineral addition, pH adjustments, and enzyme cross-linking (Liu et al. 2017; Quan and Benjakul 2019). Oxidized polyphenols are primarily used in protein cross-linkers, which enhance gel formation, e.g., β-lactoglobulin-green tea polyphenol conjugate increased B-lactoglobulin gelatin by lowering the gelling time and temperature (Balange and Benjakul 2009a,b,c; Staszewski et al. 2011, 2012; Velickovic et al. 2017). The change in the gelling properties of yogurt could be because of the addition of cocoa polyphenol, which increases the syneresis and decreases the elasticity, and gelatin could be covalently modified with tannic acid, yielding an improved rigid structure (Yildirim-Elikoglu and Erdem 2017). Additionally, the gelatin hydrogel matrix could be improved by tannic acid/caffeic acid/Fructus chebulae extract by producing a compact structure. The addition of oxidized polyphenols could increase the strength of bigeye snapper surimi gel and a similar increase could be seen with the addition of coconut husk extract to sardine surimi (Balange and Bejakul 2009a,b,c). Tea polyphenol modification to egg albumen proteins enhances gurnard surimi gels, and studies showed that protein-polyphenol conjugates have a binding ability with both hydrophilic and/or hydrophobic compounds (Chanphai et al. 2018; Chanpai et al. 2019; Zhao and Sun 2018). Moreover, protein-polyphenol conjugated emulsifiers for delivering encapsulated bioactive compounds stabilizes the β-carotene oil-in-water emulsion by improving their stability in GIT conditions.

Whey Protein-Polyphenol Conjugates and Complexes

Whey proteins (WP), a globular protein series, are found in milk, e.g., α-lactalbumin, BSA, and β-lactoglobulin, which are used as a functional ingredient in the food industry, primarily as a foaming and emulsifying encapsulating agent or as a gel structure in different products (O’Connell and Fox 1999; Krolczyk and Janiszewska-Turak 2016). Whey proteins generate peptides, which have potentially beneficial properties, e.g., antioxidant, anti-hypertension, and cholesterol lowering. This gives them health benefits, but their consumption is limited, as they are functionally deteriorated because of numerous physical influences, e.g., temperature, pH, and ionic strength (Buggy et al. 2018; Minj and Anand 2020; Baba et al. 2021; Koningsveld et al. 2002; Tokmakov et al. 2021). These processes change the structure of WPs via biological activity alteration, so their health properties are changed, as there are numerous physicochemical modifications that need to be investigated to overcome these flaws and increase the functions of WPs (Madhan et al. 2005; Cao et al. 2018; Rasouli et al. 2019). The techno-functional properties of WPs are improved by their linking to food-grade products and are bonded to polysaccharides and polyphenols via covalent linkages or noncovalent linkages (Cao et al. 2018; Setiowati et al. 2020) and thereby improve the techno-functional qualities of the protein with the biological qualities (Doost et al. 2019; Khalifa et al. 2019; Pessato et al. 2019; Wang et al. 2020a,b; Zhong et al. 2021). Recently, there have been advancements in modified protein manufacturing that resulted in enhanced biological and techno-functional properties, with rapid advances in food science technology applications (Chen et al. 2021). This review presents and evaluates studies on the characterization, fabrication, and biological and techno-functional properties of WP-polyphenol complexes and conjugates, particularly their possible applications in food industries. The aims and reviews of this article are summarized in Fig. 1, which is also helpful for researchers in utilizing whey protein-polyphenol ingredients in food products and identifies the requirements for further research.

Whey Protein-Polyphenol Interactions

Whey proteins and polyphenols are linked via noncovalent (physical) or covalent (chemical) interactions and depend upon the nature and linkage type of the whey protein and polyphenols for determining the biological and functional properties of the complexes/ conjugates produced. The noncovalent bonding is reversible and weak, which includes hydrophobic attraction, hydrogen bonding, van der Waals forces, and electrostatic links, and contains hydrophobic residues, e.g., valine, isoleucine, leucine, and tryptophan, which form hydrophobic links with aromatic non-polar rings in the polyphenols (Yildirim-Elikoglu and Erdem, 2017; Charlton et al. 2002; Damodaran et al. 2007; Tang et al. 2016). Additionally, hydrogen bonds can be formed between the polar groups of WPs and the polyphenol hydroxyl groups. When the polyphenols are charged, electrostatic interactions could be present on oppositely charged protein groups (Zhang et al. 2010).

Covalent bond conjugates are formed between WPs and one or more polyphenols, which are irreversible and strong and involve the nucleophilic groups of the WPs, e.g., -SH or -NH2 groups. Some common chemical reactions involved are alkaline and free radical-induction methods, but various other methods are also used. In each method, the reaction conditions should be monitored appropriately to obtain the desired structure, function, and composition of the conjugates; the term pure refers to commercially procured polyphenols with a purity level greater than 98%.

Table 3. Whey Protein-polyphenol Covalent Conjugation: Detection, Functional, and Production Properties

Table 4. Whey Protein-polyphenol Noncovalent Conjugation; Detection, Function, and Production Properties

FOOD APPLICATION OF WHEY PROTEIN-POLYPHENOL (WP-P) CONJUGATES AND COMPLEXES

An important techno-functional property of proteins is water solubility. Determining their use in food products and the protein-polyphenol physical interaction alters the protein solubility, so their function is also changed. For example, the conjugation of whey protein with chlorogenic acid increases the water solubility. This is probably because of the polyphenol binding to the protein surface, which increases the hydrophilicity and decreases the hydrophobic interaction of the protein molecules (Tsai and She 2006; Arimboor et al. 2011; Jiang et al. 2018). A visible decrease in the surface hydrophobicity of WP was observed after the formation of an EGCG and gallic acid complex, while the water solubility of β-lactoglobulin increased with the formation of resveratrol and anthraquinones complexes, primarily because of the surface hydrophobicity reduction after binding (Wang et al. 2014; Cao and Xiong 2017). The WP-P complexes also affect the protein interfacial properties, which influences their stability to form emulsions and foams, as there the isolate foaming capacity of WPs increased when a complex was formed with chlorogenic acid and EGCG (Jiang et al. 2018). Whey proteins have numerous charged groups, hydrogen receptors, and non-polar groups on their surface, which makes them available for hydrophobic interactions, electrostatic interactions, and hydrogen bonding (Bartolomé et al. 2000; Buitimea et al. 2016; Khalifa et al. 2018). Whey protein fibril complexes with carvacrol improves the film-forming ability, emulsifying ability, and their antimicrobial activity; WP complex formation with xanthone enhances the protein emulsifying property compared to WPs alone (Rahayu et al. 2020; Wang et al. 2020a,b). The emulsion stability was improved because of the reduction in hydrophobic attraction and increased electrostatic and steric repulsion between the protein-coated oil drops. Jiang et al. (2020) and Li et al. (2020) studied the increasing foam stability and capacity after complexation with proanthocynidins in a dose-dependent way and these improvements were because of the increasing interfacial layer elasticity around the air bubbles or oil drops. The air bubbles inhibit them from coalescing or collapsing, and the increased emulsification is because of additional protein solubility after making the complex, as well as facilitating rapid protein transfer to the interfacial layers (Jiang et al. 2018). However, a protein-polyphenol complex must be carefully produced to obtain the desired interfacial properties (Zhan et al. 2020).

IMPACT OF WP-P ON HEALTH PROMOTING PROPERTIES

The whey protein-polyphenol complex has numerous effects on bioactive qualities; e.g., the complex can reduce the antioxidant ability of the polyphenol because of the masking effect (Adrar et al. 2019). Additionally, a WP complex with EGCG enhances the antioxidant activity of the polyphenol during the long-term storage and GIT conditions. Furthermore, it was explained by Chen et al. (2019a,b) that this complex preserved up to 27% of the antioxidant ability for 7 d of storage. The radical scavenging ability of EGCG-WPI complexes could be increased via sonication after storage, while the pre-heating of the milk protein polyphenol mixture reduces its antioxidant ability (Relkin and Shukat 2012; Clion et al. 2019). This could be because of the thermal denaturation of the WPs, which increases polyphenol binding to the protein exposed hydrophobic patches; however, additional study is still required to understand the required techniques for the production of WP complexes (Papadopoulou et al. 2004; Bayraktar et al. 2019). The radical scavenging ability of polyphenols is further reduced with α-lactalbumin compared to lactoferrin and β-lactoglobulin, which could be because of the polyphenol binding tendency for WPs, while the antioxidant activity of some anthraquinones–β-lactoglobulin complexes was reduced because of the complex formation (Stojadinovic et al. 2013; Xu et al. 2019a,b,c). Some WP-P complexes showed improved antioxidant activity compared to alone, e.g., resveratrol, phenolic acids, and curcumin, and the antioxidant property and heat stability of resveratrol was increased in a β-lactoglobulin complex. This could be because of the proteins’ ability to prevent the resveratrol from converting from the trans to cis form (Cheng et al. 2018; Guo and Jauregi 2018; Li et al. 2018; Wu et al. 2018a, b). The stability of grape skin anthocyanin extract was increased regarding color retention with different destabilizing agents, i.e., by β-lactoglobulin and β-lactoglobulin-quercetin complexes, as it was protected by a polysaccharide, and is a method to release the protected quercetin from acidic stomach degradation. In addition, it has been indicated in multiple studies that the β-lactoglobulin polyphenol complex enhances the polyphenol availability (He et al. 2016; Mirpoor et al. 2017; Shafaei et al. 2017; Chanphai et al. 2018). Protein-polyphenol complexes decrease the allergenicity of WPs, e.g., delphinidin-3-O-glucoside, theaflavins, and chlorogenic acid reduce β-lactoglobulins binding via IgE epitomes. The allergenicity of BSA and β-lactoglobulin was reduced by complexation with EGCG at different pHs and WP oral sensitization of WP was decreased when complexed with caffeic acid and EGCG (Pessato et al. 2018, 2019). As a result, many WPs are used as delivery systems to improve the function of polyphenols, and these systems are then used as functional food fortification for health benefits (Al-Hanish et al. 2016; Chanphai and Tajmir-Riahi 2019).

IMPACT OF WP-P ON TECHNO-FUNCTIONAL PROPERTIES

The covalent bonds of polyphenol-WPs modify their techno-functional properties; e.g., WPs conjugation causes the partial unfolding of WP molecules and exposes the surface hydrophobic sites, which causes enhanced emulsifying, foaming, and solubility properties of the proteins (Temdee and Benjakul 2015; Xu et al. 2019a,b,c). Whey protein complexes with lotus seed proanthocyanidins enhance the emulsifying/oxidative/thermal stability of the WP, and the conjugation of WPs with mulberry polyphenols enhances the solubility and textural properties and decreases their ability to foam glycated end products (Khaifa et al. 2019; Chen et al. 2021). Different polyphenols, e.g., gallic acid, chlorogenic acid, and EGCG, conjugate with lactoferrin via free radical scavenging, which enhances the emulsification and thermal stability as well as produces emulsions, and provides a resistance to salt, freezing, thawing, UV exposure, and thermal applications (Liu et al. 2015, 2017; Lang et al. 2019). Moreover, EGCG and chlorogenic acid prevent lactoferrin aggregation by producing steric/electrostatic repulsions in protein molecules and also change the protein isoelectric points to control pH-induced aggregation (Liu et al. 2015). β-Lactoglobulin-catechin conjugates improve the physicochemical stability of β-carotene, which results in storage carotenoid retention. In addition, α-lactalbumin-catechin conjugates also are stabilized chemically via the radical scavenging from surface polyphenols (Yi et al. 2014, 2016). β-Lactoglobulin-chlorogenic acid conjugates improve the stability and inhibit EGCG release, while BSA-caffeic acid conjugates have better antioxidant activity with enhanced chemical stability and resveratrol bioavailability (Liu et al. 2017; Fan et al. 2018a,b; Prasanna and Jing 2018). Whey proteins have improved interfacial stability with polyphenol conjugation, and when covalently linked covalently with EGCG, many WPs had enhanced interfacial properties compared to their noncovalent complexes (Wei et al. 2015). The improving tendency of WP-EGCG conjugates in terms of β-carotene emulsion stability is in the following order: β-lactoglobulin is greater or equal to α-lactalbumin, which is greater or equal to lactoferrin, as their functional properties depend on the polyphenol type (Ali 2019). In a study, a WP-rosmarinic acid conjugate, made via enzymatic methods, had better antioxidant and antimicrobial activity than the conjugate made via an alkaline method, so it should be necessary to further study the protein, polyphenols, and enzymes used to form different conjugates. Whey protein-polyphenol conjugates have health benefits with enhanced biological activity, as these conjugates have increased antioxidant properties because of the surface hydroxyl groups after adding polyphenol (Fan et al. 2017). Whey protein-chlorogenic acid conjugates have increased antioxidant quality and digestibility but decreased allergenicity, and it was also found that β-lactoglobulin-caffeic acid conjugates were DPPH radical scavengers, with more caffeic acid molecules attached to proteins (El-Maksoud et al. 2018; Xu et al. 2019a,b,c). Conjugates produced via the free radical method, e.g., β-lactoglobulin-chlorogenic acid/lactoferrin, have enhanced antioxidant properties; as such, EGCG-β-lactoglobulin conjugate is beneficial for LDL oxidation, inhibiting atherosclerosis, primarily because of the metal chelation and radical scavenging activity (Liu et al. 2015; Fan et al. 2017; Tao et al. 2019; Liang et al. 2007). Catechin-α-lactalbumin conjugate has an improved scavenging ability compared to its protein or polyphenol alone, which shows their synergistic effect, while a WP-onion extract/quercetin conjugate showed anticancer abilities in human lungs and WP-rosmarinic acid/ chlorogenic acid has improved antioxidant/antiviral activities compared to native proteins.

FUTURE DIRECTIONS

The biological and functional activities of protein-polyphenol complexes or conjugates depend on their nature and cross-linking method type, so more rational complexes or conjugates can be designed in the future. As such, a greater understanding is required in terms of the function structure relation of WP-P conjugates and complexes for specific applications, and modern techniques; e.g., high-pressure processing and sonication, must be utilized for system performance. For example, sonication increased the thermal stability and solubility of a cyanidin-3-galactoside-soy protein conjugate, whereas the performance of an α-lactalbumin pelargonidin-3-glucoside conjugate was improved via the high-pressure method (Xu et al. 2018; Zou et al. 2019). Until now, there have been limited studies on the GIT biological activity and WP-P conjugate/complex health benefits, as their interaction may change the generated peptide, so in terms of altering the protein bioactivity and allergenicity, additional focus is required in this area.

CONCLUSIONS

  1. Protein-phenolic interaction can be covalent or noncovalent, but most of the published studies have focused on the noncovalent interactions, mostly because of the lack of methods for covalent bond analysis. Some of the primary factors affecting protein-polyphenol reactions are the protein type and structure and various environmental factors, e.g., pH, temperature, salt concentration, and presence of other reagents. As an exact process, the interactions are still unknown, and studies have been performed on the changes in the structural and functional protein properties.
  2. Phenolic fortification could improve the health benefits of food products, but their interaction with food components (especially proteins) could have some undesirable effects on protein digestibility and antioxidative activity. Therefore, additional studies and research are required regarding the protein-phenolic interactions under different environmental conditions for the development of phenolic functional foods with the desired nutritional benefits.
  3. Proteins and polyphenols have specific functions, e.g., proteins being able to produce gel or stabilize emulsion and polyphenols having bioactivity and antioxidant activity, which influences food quality. Protein-polyphenol interaction can occur via the enzymatic or non-enzymatic method which is affected by various environmental conditions such as pH, temperature, and structure of the protein/polyphenols.
  4. Protein-polyphenol conjugates have improved emulsifying and antioxidative properties, which increases food efficacy, and must be further studied for developing products with enhanced functional, nutritional, and sensorial properties.
  5. Whey protein-polyphenol produces conjugates or complexes via covalent/noncovalent bonding, which produces multiple food ingredients, e.g., foaming agents, antioxidants, emulsifiers, and structure formers. Their performance depends on the production method and WP-P type and concentration. A detailed understanding of protein-polyphenol interactions is essential to producing novel ingredients in a food system application, as their internal food system behavior is still not known.
  6. The effect on bioactivity and functional properties of the ingredients are barely understood during the preparation, storage consumption, and digestion.
  7. As there are a variety of polyphenol structures and functions, a protein-polyphenol ingredient must be produced with wider functions and rational designing. However, it is also important that these methods are viable economically and meet the food requirements.

ACKNOWLEDGEMENTS

The authors are thankful to the Universiti Malaysia Sarawak (Malaysia), South Ural State University (Russian Federation) and Zhangir Khan Agrarian Technical University (Republic of Kazakhstan) for their help and support in completing this work.

REFERENCES CITED

Abdelfatah, A. M. K. (2013). Interactions of Food Proteins with Plant Phenolics – Modulation of Structural, Techno-and Bio-functional Properties of Proteins, Ph.D. Dissertation, University of Potsdam, Potsdam, Germany.

Adilah, Z. A. M., Jamilah, B., and Hanani, Z. A. N. (2018). “Functional and antioxidant properties of protein-based films incorporated with mango kernel extract for active packaging,” Food Hydrocolloids 74, 207-218. DOI: 10.1016/J.FOODHYD.2017.08.017

Adrar, N. S., Madani, K., and Adrar, S. (2019). “Impact of the inhibition of proteins activities and the chemical aspect of polyphenols-proteins interactions,” PharmaNutrition 7, 1-12. DOI: 10.1016/J.PHANU.2019.100142

Aewsiri, T., Benjakul, S., Visessanguan, W., Eun, J.-B., Wierenga, P. A., and Gruppen, H. (2009). “Antioxidative activity and emulsifying properties of cuttlefish skin gelatin modified by oxidised phenolic compounds,” Food Chemistry 117(1), 160-168. DOI: 10.1016/j.foodchem.2009.03.092

Akhtar, M., and Dickinson, E. (2003). “Emulsifying properties of whey protein–dextran

conjugates at low pH and different salt concentrations,” Colloids and Surfaces B:

Biointerfaces 31, 125-132.

Al-Hanish, A., Stanic-Vucinic, D., Mihailovic, J., Prodic, I., Minic, S., Stojadinovic, M., Radibratovic, M., Milcic, M., and Velickovic, T. C. (2016). “Noncovalent interactions of bovine α-lactalbumin with green tea polyphenol, epigalocatechin-3-gallate,” Food Hydrocolloids 61, 241-250. DOI: 10.1016/J.FOODHYD.2016.05.012

Ali, M., Homann, T., Khalil, M., Kruse, H.-P., and Rawel, H. (2013). “Milk whey protein modification by coffee-specific phenolics: Effect on structural and functional properties,” Journal of Agricultural and Food Chemistry 61(28), 6911-6920. DOI: 10.1021/JF402221M

Ali, M. (2016). Effect of Interaction of Food Proteins with Secondary Plant Metabolites – Consequences on Structural and Functional Properties, Ph.D. Dissertation, University of Potsdam, Potsdam, Germany.

Ali, M., and Elsebaie, E. (2018). “Milk whey proteins and onion extract powder interactions – Antimicrobial and anticancer activities,” Journal of Agroalimentary Processes and Technologies 24(3), 152-160.

Ali, M., and Elsharkawy. M. M. (2018). “Characterization of whey protein isolate covalently modified with phenolic compounds 1: Antioxidant and antiviral activities,” Journal of Food and Dairy Science 9(12), 385-393. DOI: 10.21608/JFDS.2018.36092

Ali, M., Keppler, J. K., Coenye, T., and Schwarz, K. (2018). “Covalent whey protein-rosmarinic acid interactions: A comparison of alkaline and enzymatic modifications on physicochemical, antioxidative, and antibacterial properties,” Journal of Food Science 83(8), 2092-2100. DOI: 10.1111/1750-3841.14222

Ali, M. (2019). “Chemical, structural and functional properties of whey proteins covalently modified with phytochemical compounds,” Journal of Food Measurement and Characterization 13, 2970-2979. DOI: 10.1007/s11694-019-00217-1

Arimboor, R., and Arumughan, C. (2011). “Sea buckthorn (Hippophae rhamnoides) proanthocyanidins inhibit in vitro enzymatic hydrolysis of protein,” Journal of Food Science 76(6), T130-T137. DOI: 10.1111/j.1750-3841.2011.02238.x

Arts, M. J. T. J., Haenen, G. R. M. M., Voss, H.-P., and Bast, A. (2001). “Masking of antioxidant capacity by the interaction of flavonoids with protein,” Food Chemical Toxicological 39(8) 787-791. DOI: 10.1016/S0278-6915(01)00020-5

Baba, W. N., Mudgil, P., Kamal, H., Kilari, B. P., Gan, C.-Y., and Maqsood, S. (2021). “Identification and characterization of novel α-amylase and α-glucosidase inhibitory peptides from camel whey proteins,” Journal of Dairy Science 104(2), 1364-1377. DOI: 10.3168/JDS.2020-19271

Balange, A. K., and Benjakul, S. (2009a). “Effect of oxidised tannic acid on the gel properties of mackerel (Rastrelliger kanagurta) mince and surimi prepared by different washing processes,” Food Hydrocolloids 23(7), 1693-1701. DOI: 10.1016/J.FOODHYD.2009.01.007

Balange, A., and Benjakul, S. (2009b). “Enhancement of gel strength of bigeye snapper (Priacanthus tayenus) surimi using oxidised phenolic compounds,” Food Chemistry 113(1) 61-70. DOI: 10.1016/J.FOODCHEM.2008.07.039

Balange, A. K., and Benjakul, S. (2009c). “Effect of oxidised phenolic compounds on the gel property of mackerel (Rastrelliger kanagurta) surimi,” LWT – Food Science and Technology 42(6), 1059-1064. DOI: 10.1016/J.LWT.2009.01.013

Bartolomé, B., Estrella, I., and Hernández, M. T. (2000). “Interaction of low molecular weight phenolics with proteins (BSA),” Journal of Food Science 65(4), 617-621. DOI: 10.1111/J.1365-2621.2000.TB16060.X

Bayraktar, M. K., Harbourne, N. B., and Fagan, C.C. (2019). “Impact of heat treatment and acid gelation on polyphenol enriched milk samples,” LWT 113, 1-7. DOI: 10.1016/j.lwt.2019.108282

Bonomi, F., Iametti, S., Pagliarini, E., and Peri, C. (1988). “A spectrofluorimetric approach to the estimation of the surface hydrophobicity modifications in milk proteins upon thermal treatment,” Milchwissenschaft 43(5), 281-285.

Bourvellec, C. L., and Renard, C. M. G. C. (2012). “Interactions between polyphenols and macromolecules: Quantification methods and mechanisms,” 52(3), 213-248. DOI: 10.1080/10408398.2010.499808

Buamard, N., and Benjakul, S. (2017). “Cross-linking activity of ethanolic coconut husk extract toward sardine (Sardinella albella) muscle proteins,” Journal of Food Biochemistry 41(2), 1-9. DOI: 10.1111/JFBC.12283

Buamard, N., and Benjakul, S. (2018). “Combination effect of high pressure treatment and ethanolic extract from coconut husk on gel properties of sardine surimi,” LWT 91, 361-367. DOI: 10.1016/J.LWT.2018.01.074

Buchner, N., Krumbein, A., Rohn, S., and Kroh, L. W. (2006). “Effect of thermal processing on the flavonols rutin and quercetin,” Rapid Communications in Mass Spectrometry 20(21), 3229-3235. DOI: 10.1002/RCM.2720

Buggy, A. K., McManus, J. J., Brodkorb, A., Hogan, S. A., and Fenelon, M. A. (2018). “Pilot-scale formation of whey protein aggregates determine the stability of heat-treated whey protein solutions – Effect of pH and protein concentration,” Journal of Dairy Science 101(12), 10819-10830. DOI: 10.3168/JDS.2017-14177

Buitimea-Cantúa, N. E., Gutiérrez-Uribe, J. A., and Serna-Saldívar, S. O. (2016).
“Phenolic-protein interactions: Effects on food properties and health benefits,” Journal of Medicinal Food 21(2), 188-198. DOI: 10.1089/JMF.2017.0057

Cao, Y., and Xiong, Y. L. (2017). “Interaction of whey proteins with phenolic derivatives under neutral and acidic pH conditions,” Journal of Food Science 82(2), 409-419. DOI: 10.1111/1750-3841.13607

Cao, Y., Xiong, Y. L., Cao, Y., and True, A. D. (2018). “Interfacial properties of whey protein foams as influenced by preheating and phenolic binding at neutral pH,” Food Hydrocolloids 82(1), 379-387. DOI: 10.1016/J.FOODHYD.2018.04.020

Chanphai, P., and Tajmir-Riahi, H. A. (2019). “Tea polyphenols bind serum albumins: A potential application for polyphenol delivery,” Food Hydrocolloids 89(1), 461-467. DOI: 10.1016/J.FOODHYD.2018.11.008

Chanphai, P., Bourassa, P., Kanakis, C. D., Tarantilis, P. A., Polissiou, M. G., and Tajmir-Riahi, H. A. (2018). “Review on the loading efficacy of dietary tea polyphenols with milk proteins,” Food Hydrocolloids 77(1), 322-328. DOI: 10.1016/J.FOODHYD.2017.10.008

Charlton, A. J., Baxter, N. J., Khan, M. L., Moir, A. J. G., Haslam, E., Davies, A. P., and Williamson, M. P. (2002). “Polyphenol/peptide binding and precipitation,” Journal of Agricultural and Food Chemistry 50(6), 1593-1601. DOI: 10.1021/jf010897z

Cheetangdee, N., and Benjakul, S. (2017). “Effects of rice hull phenolic extract on the stability of emulsions stabilized by rice bran protein hydrolysate,” International Food Research Journal 24(4), 1588-1594.

Chen, W., Wang, W., Ma, X., Lv, R., Watharkar, R. B., Ding, T., Ye, X., and Liu, D. (2019a). “Effect of pH-shifting treatment on structural and functional properties of whey protein isolate and its interaction with (-)-epigallocatechin-3-gallate,” Food Chemistry 274, 234-241. DOI: 10.1016/J.FOODCHEM.2018.08.106

Chen, Y., Jiang, S., Chen, Q., Liu, Q., and Kong, B. (2019b). “Antioxidant activities and emulsifying properties of porcine plasma protein hydrolysates modified by oxidized tannic acid and oxidized chlorogenic acid,” Process Biochemistry 79, 105-113. DOI: 10.1016/J.PROCBIO.2018.12.026

Chen, Y., Wang, C., Liu, H., Liu, Q., and Kong, B. (2018). “Enhanced physical and oxidative stability of porcine plasma protein hydrolysates based oil-in-water emulsions by adding oxidized chlorogenic acid,” Colloids and Surfaces A: Physicochemical and Engineering Aspects 558, 330-337. DOI: 10.1016/J.COLSURFA.2018.08.067

Chen, Y., Huang, F., Xie, B., Sun, Z., McClements, D. J., and Deng, Q. (2021). “Fabrication and characterization of whey protein isolates- lotus seedpod proanthocyanin conjugate: Its potential application in oxidizable emulsions,” Food Chemistry 346, 1-11. DOI: 10.1016/J.FOODCHEM.2020.128680

Cheng, H., Fang, Z., Wusigale, Bakry, A. M., Chen, Y., and Liang, L. (2018).
“Complexation of trans- and cis-resveratrol with bovine serum albumin, β-lactoglobulin or α-lactalbumin,” Food Hydrocolloids 81, 242-252. DOI: 10.1016/J.FOODHYD.2018.02.037

Chung, J. E., Kurisawa, M., Uyama, H., and Kobayashi, S. (2003). “Enzymatic synthesis and antioxidant property of gelatin-catechin conjugates,” Biotechnology Letters 25, 1993-1997. DOI: 10.1023/B:BILE.0000004391.27564.8E

Clion, V., Pottier, L., and Lamballerie, M. d. (2019). “Whey proteins-epicatechin interactions in a model specialized food product treated by high pressure,” 39(2), 374-384. DOI: 10.1080/08957959.2019.1608986

Costa, M., Losada-Barreiro, S., Paiva-Martins, F., and Bravo-Díaz, C. (2021). “Polyphenolic antioxidants in lipid emulsions: Partitioning effects and interfacial phenomena,” Foods 10, article no. 539. DOI: 10.3390/foods10030539.

Crozier, A., Jaganath, I. B., and Clifford, M. N. (2009). “Dietary phenolics: Chemistry, bioavailability and effects on health,” Natural Products Reports 26(8), 1001-1043. DOI: 10.1039/B802662A

Czajkowska–González, Y. A., Alvarez-Parrilla, E., Martínez-Ruiz, N. d. R., Vázquez-Flores, A. A., Gaytán-Martínez, M., and de la Rosa, L. A. (2021). “Addition of phenolic compounds to bread: Antioxidant benefits and impact on food structure and sensory characteristics,” Food Production, Processing and Nutrition 3, article no. 25. DOI: 10.1186/s43014-021-00068-8

Czubinski, J., and Dwiecki, K. (2016). “A review of methods used for investigation of protein–phenolic compound interactions,” International Journal Food Science Technology 52(3), 573-585. DOI: 10.1111/IJFS.13339

Damodaran, S., Parkin, K. L., and Fennema, O. R. (2007). Fennema’s Food Chemistry Fourth Edition, CRC Press, Boca Raton, FL.

Doost, A. S., Nasrabadi, M. N., Wu, J., A’yun, Q., and Meeren, P. V. d. (2019). “Maillard conjugation as an approach to improve whey proteins functionality: A review of conventional and novel preparation techniques,” Trends in Food Science & Technology 91, 1-11. DOI: 10.1016/J.TIFS.2019.06.011

Dubeau, S., Samson, G., and Tajmir-Riahi, H. A. (2010). “Dual effect of milk on the antioxidant capacity of green, Darjeeling, and English breakfast teas,” Food Chemistry 122(3), 539-545. DOI: 10.1016/J.FOODCHEM.2010.03.005

El-Maksoud, A. A. A., El-Ghany, I. H. A., El-Beltagi, H. S., Anankanbil, S., Banerijee, C., Petersen, S. V., Pérez, B., and Guo, Z. (2018). “Adding functionality to milk-based protein: Preparation, and physico-chemical characterization of β-lactoglobulin-phenolic conjugates,” Food Chemistry 241, 281-289. DOI: 10.1016/J.FOODCHEM.2017.08.101

Emmambux, N. M., and Taylor, J. R. N. (2003). “Sorghum kafirin interaction with various phenolic compounds,” Journal of the Science of Food and Agriculture 83(5), 402-407. DOI: 10.1002/JSFA.1379

Fan, Y., Zhang, Y., Yokoyama, W., and Yi, J. (2017). “β-lactoglobulin–chlorogenic acid conjugate-based nanoparticles for delivery of (-)-epigallocatechin-3-gallate,” RSC Advances 7(7), 21366-21374. DOI: 10.1039/C6RA28462K

Fan, Y., Liu, Y., Gao, L., Zhang, Y., and Yi, J. (2018a). “Improved chemical stability and cellular antioxidant activity of resveratrol in zein nanoparticle with bovine serum albumin-caffeic acid conjugate,” Food Chemistry 261, 283-291. DOI: 10.1016/J.FOODCHEM.2018.04.055

Fan, Y., Liu, Y., Gao, L., Zhang, Y., and Yi, J. (2018b). “Oxidative stability and in vitro digestion of menhaden oil emulsions with whey protein: Effects of EGCG conjugation and interfacial cross-linking,” Food Chemistry 265, 200-207. DOI: 10.1016/J.FOODCHEM.2018.05.098

Felton, G. W., Broadway, R. M., and Duffey, S. S. (1989). “Inactivation of protease inhibitor activity by plant-derived quinones: Complications for host-plant resistance against noctuid herbivores,” Journal of Insect Physiology 35(12), 981-990. DOI: 10.1016/0022-1910(89)90022-X

Feng, J., Cai, H., Wang, H., Li, C., and Liu, S. (2018). “Improved oxidative stability of fish oil emulsion by grafted ovalbumin-catechin conjugates,” Food Chemistry 241, 60-69. DOI: 10.1016/J.FOODCHEM.2017.08.055

Ferraro, V., Madureira, A. R., Sarmento, B., Gomes, A., and Pintado, M. E. (2015). “Study of the interactions between rosmarinic acid and bovine milk whey protein α-lactalbumin, β-lactoglobulin and lactoferrin,” Food Research International 77(3), 450-459. DOI: 10.1016/J.FOODRES.2015.08.024

Frazier, R. A., Deaville, E. R., Green, R. J., Stringano, E., Willoughby, I., Plant, J., and Mueller-Harvey, I. (2010). “Interactions of tea tannins and condensed tannins with proteins,” Journal of Pharmaceutical and Biomedical Analysis 51(2), 490-495. DOI: 10.1016/J.JPBA.2009.05.035

Frazier, R. A., Papadopoulou, A., and Green, R. J. (2006). “Isothermal titration calorimetry study of epicatechin binding to serum albumin,” Journal of Pharmaceutical and Biomedical Analysis 41(5), 1602-1605. DOI: 10.1016/J.JPBA.2006.02.004

Groth, S., Budke, C., Weber, T., Neugart, S., Brockmann, S., Holz, M., Sawadski, B. C., Daum, D., and Rohn, S. (2021). “Relationship between phenolic compounds, antioxidant properties, and the allergenic protein Mal d 1 in different selenium‐biofortified apple cultivars (Malus domestica),” Molecules 26, article no. 2647. DOI: 10.3390/molecules26092647

Gu, L., Peng, N., Chang, C., McClements, D. J., Su, Y., and Yang, Y. (2017). “Fabrication of surface-active antioxidant food biopolymers: Conjugation of catechin polymers to egg white proteins,” Food Biophysics 12, 198-210. DOI: 10.1007/s11483-017-9476-5

Guo, A., Jiang, J., True, A. D., and Xiong, Y. L. (2021). “Myofibrillar protein cross-linking and gelling behavior modified by structurally relevant phenolic compounds,” Journal of Agricultural and Food Chemistry 69, 1308-1317. DOI: 10.1021/acs.jafc.0c04365

Guo, A., and Xiong, Y. L. (2021). “Myoprotein–phytophenol interaction: Implications for muscle food structure‐forming properties,” Comprehensive Reviews in Food Science and Food Safety. DOI: 10.1111/1541-4337.12733

Guo, Y., and Jauregi, P. (2018). “Protective effect of β-lactoglobulin against heat induced loss of antioxidant activity of resveratrol,” Food Chemistry 266, 101-109. DOI: 10.1016/J.FOODCHEM.2018.05.108

He, Z., Zhu, H., Xu, M., Zeng, M., Qin, F., and Chen, J. (2016). “Complexation of bovine β-lactoglobulin with malvidin-3-O-glucoside and its effect on the stability of grape skin anthocyanin extracts,” Food Chemistry 209, 234-240. DOI: 10.1016/J.FOODCHEM.2016.04.048

Jiang, J., Zhang, Z., Zhao, J., and Liu, Y. (2018). “The effect of noncovalent interaction of chlorogenic acid with whey protein and casein on physicochemical and radical-scavenging activity of in vitro protein digests,” Food Chemistry 268, 334-341. DOI: 10.1016/j.foodchem.2018.06.015

Jiang, Z., Li, T., Ma, L., Chen, W., Yu, H., Abdul, Q., Hou, J., and Tian, B. (2020). “Comparison of interaction between three similar chalconoids and α-lactalbumin: Impact on structure and functionality of α-lactalbumin,” Food Research International 131, 1-16. DOI: 10.1016/J.FOODRES.2020.109006

Jongberg, S., Lund, M. N., and Otte, J. (2015). “Dissociation and reduction of covalent β-lactoglobulin–quinone adducts by dithiothreitol, tris(2-carboxyethyl)phosphine, or sodium sulfite,” Analytical Biochemistry 478, 40-48. DOI: 10.1016/J.AB.2015.02.008

Kaewprachu, P., Rungraeng, N., Osako, K., and Rawdkuen, S. (2017). “Properties of fish myofibrillar protein film incorporated with catechin-Kradon extract,” Food Packaging and Shelf Life 13, 56-65. DOI: 10.1016/J.FPSL.2017.07.003

Kanakis, C. D., Hasni, I., Bourassa, P., Tarantilis, P. A., Polissiou, M. G., and Tajmir-Riahi H. A. (2011). “Milk β-lactoglobulin complexes with tea polyphenols,” Food Chemistry 127(3), 1046-1055. DOI: 10.1016/J.FOODCHEM.2011.01.079

Khalifa, I., Nie, R., Ge, Z., Li, K., and Li C. (2018). “Understanding the shielding effects of whey protein on mulberry anthocyanins: Insights from multispectral and molecular modelling investigations,” International Journal of Biological Macromolecules 119, 116-124. DOI: 10.1016/J.IJBIOMAC.2018.07.117

Khalifa, I., Peng, J., Jia, Y., Li, J., Zhu, W., Yu-juan, X., and Li, C. (2019). “Anti-glycation and anti-hardening effects of microencapsulated mulberry polyphenols in high-protein-sugar ball models through binding with some glycation sites of whey proteins,” International Journal of Biological Macromolecules 123, 10-19. DOI: 10.1016/J.IJBIOMAC.2018.11.016

Koningsveld, G. A. v., Gruppen, H., Jongh, H. H. J. d., Wijngaards, G., Boekel, M. A. J. S. v., Walstra, P., and Voragen, A. G. J. (2002). “The solubility of potato proteins from industrial potato fruit juice as influenced by pH and various additives,” Journal of the Science of Food and Agriculture 82(1), 134-142. DOI: 10.1002/JSFA.1015

Korpela, B., Pitkänen, L., and Heinonen, M., (2022). “Enzymatic modification of oat globulin enables covalent interaction with procyanidin B2,” Food Chemistry 395, article no. 133568. DOI: 10.1016/j.foodchem.2022.133568

Królczyk, J. B., Dawidziuk, T., Janiszewska-Turak, E., and Solowiej, B. (2016). “Use of whey and whey preparations in the food industry – A review,” Polish Journal of Food and Nutrition Sciences 66(3), 157-165. DOI: 10.1515/pjfns-2015-0052

Kroll, J., Rawel, H. M., and Rohn, S. (2003). “Reactions of plant phenolics with food proteins and enzymes under special consideration of covalent bonds,” Food Science Technology Research 9(3), 205-218. DOI: 10.3136/fstr.9.205

Kulmyrzaev, A. A., Levieux, D., and Dufour, É. (2005). “Front-face fluorescence spectroscopy allows the characterization of mild heat treatments applied to milk. Relations with the denaturation of milk proteins,” Journal of Agricultural and Food Chemistry 53(3), 502-507. DOI: 10.1021/JF049224H

Labuckas, D. O., Maestri, D. M., Perelló, M., Martínez, M. L., and Lamarque, A. L. (2008). “Phenolics from walnut (Juglans regia L.) kernels: Antioxidant activity and interactions with proteins,” Food Chemistry 107(2), 607-612. DOI: 10.1016/J.FOODCHEM.2007.08.051

Lang, Y., Li, E., Meng, X., Tian, J., Ran, X., Zhang, Y., Zang, Z., Wang, W., and Li, B. (2019). “Protective effects of bovine serum albumin on blueberry anthocyanins under illumination conditions and their mechanism analysis,” Food Research International 122, 487-495. DOI: 10.1016/J.FOODRES.2019.05.021

Li, T., Hu, P., Dai, T., Li, P., Ye, X., Chen, J., and Liu, C. (2018). “Comparing the binding interaction between β-lactoglobulin and flavonoids with different structure by multi-spectroscopy analysis and molecular docking,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 201, 197-206. DOI: 10.1016/J.SAA.2018.05.011

Li, X., Dai, T., Hu, P. Zhang, C., Chen, J., Liu, C., and Li, T. (2020). “Characterization the noncovalent interactions between beta lactoglobulin and selected phenolic acids,” Food Hydrocolloids 105, 1-9. DOI: 10.1016/J.FOODHYD.2020.105761

Li, Y., Liu, H., Liu, Q., Kong, B., and Diao, X. (2019). “Effects of zein hydrolysates coupled with sage (salvia officinalis) extract on the emulsifying and oxidative stability of myofibrillar protein prepared oil-in-water,” Food Hydrocolloids 87, 149-157. DOI: 10.1016/j.foodhyd.2018.07.052

Liang, L., Tajmir-Riahi, H.A., and Subirade, M. (2007). “Interaction of β-lactoglobulin with resveratrol and its biological implications,” Biomacromolecules 9(1), 50-56. DOI: 10.1021/BM700728K

Liu, J., Ru, Q., and Ding, Y. (2012). “Glycation a promising method for food protein modification. Physicochemical properties and structure, a review,” Food Research International 49, 170-183.

Liu, F., Ma, C., Gao, Y., and McClements, D. J. (2013). “Food-grade covalent complexes and their application as nutraceutical delivery systems: A review,” Comprehensive Reviews in Food Science and Food Safety 16(1), 76-95. DOI: 10.1111/1541-4337.12229

Liu, F., Sun, C., Yang, W., Yuan, F., and Gao, Y. (2015). “Structural characterization and functional evaluation of lactoferrin–polyphenol conjugates formed by free-radical graft copolymerization,” RSC Advances 5, 15641-15651. DOI: 10.1039/C4RA10802G

Liu, F., Wang, D., Ma, C., and Gao, Y. (2016a). “Conjugation of polyphenols prevents lactoferrin from thermal aggregation at neutral pH,” Food Hydrocolloids 58, 49-59. DOI: 10.1016/J.FOODHYD.2016.02.011

Liu, F., Wang, D., Sun, C., McClements, D. J., and Gao, Y. (2016b). “Utilization of interfacial engineering to improve physicochemical stability of β-carotene emulsions: Multilayer coatings formed using protein and protein–polyphenol conjugates,” Food Chemistry 205, 129-139. DOI: 10.1016/J.FOODCHEM.2016.02.155

Liu, F. Ma, C., McClements, D. J., and Gao, Y. (2017). “A comparative study of covalent and noncovalent interactions between zein and polyphenols in ethanol-water solution,” Food Hydrocolloids 63, 625-634. DOI: 10.1016/J.FOODHYD.2016.09.041

Liu, F., Zhang, S., Li, J., McClements, D. J., and Liu, X. (2018). “Recent development of lactoferrin-based vehicles for the delivery of bioactive compounds: Complexes, emulsions, and nanoparticles,” Trends in Food Science & Technology 79, 67-77. DOI: 10.1016/J.TIFS.2018.06.013

Madhan, B., Subramanian, V., Rao, J. R., Nair, B. U., and Ramasami T. (2005). “Stabilization of collagen using plant polyphenol: Role of catechin,” International Journal of Biological Macromolecules 37(1-2), 47-53. DOI: 10.1016/J.IJBIOMAC.2005.08.005

Maqsood, S., Benjakul, S., and Shahidi, F. (2012). “Emerging role of phenolic compounds as natural food additives in fish and fish products,” Critical Reviews in Food Science and Nutrition 53(2), 162-179. DOI: 10.1080/10408398.2010.518775

McRae, J. M., and Kennedy, J. A. (2011). “Wine and grape tannin interactions with salivary proteins and their impact on astringency: A review of current research,” Molecules 16(3), 2348-2364. DOI: 10.3390/MOLECULES16032348

Minj, S., and Anand, S. (2020). “Whey proteins and its derivatives: Bioactivity, functionality, and current applications,” Dairy 1(3), 233-258. DOI: 10.3390/DAIRY1030016

Mirpoor, S. F., Hosseini, S. M. H, and Nekoei, A. R. (2017). “Efficient delivery of quercetin after binding to beta-lactoglobulin followed by formation soft-condensed core-shell nanostructures,” Food Chemistry 233, 282-289. DOI: 10.1016/J.FOODCHEM.2017.04.126

Morais, F. P. R. d., Pessato, T. B., Rodrigues, E., Mallmann L. P., Mariutti, L. R. B., and Netto, F. M. (2020). “Whey protein and phenolic compound complexation: Effects on antioxidant capacity before and after in vitro digestion,” Food Research International 133, 1-11. DOI: 10.1016/J.FOODRES.2020.109104

Mulaudizi, R. B., Ndhlala, A. R., Kulkarni, M. G., and Staden, J. V. (2012). “Pharmacological properties and protein binding capacity of phenolic extracts of some Venda medicinal plants used against cough and fever,” Journal of Ethnopharmacology 143(1), 185-193. DOI: 10.1016/J.JEP.2012.06.022

Naczk, M., Grant, S., Zadernowski, R., and Barre E. (2006). “Protein precipitating capacity of phenolics of wild blueberry leaves and fruits,” Food Chemistry 96(4), 640-647. DOI: 10.1016/J.FOODCHEM.2005.03.017

Naczk, M., Oickle, D., Pink, D., and Shahidi, F. (1996). “Protein precipitating capacity of crude canola tannins:  Effect of pH, tannin, and protein concentrations,” Journal of Agricultural and Food Chemistry 44(8), 2144-2148. DOI: 10.1021/JF960165K

Nagarajan, M., Benjakul, S., Prodpran, T., and Songtipya, P. (2015). “Properties and characteristics of nanocomposite films from tilapia skin gelatin incorporated with ethanolic extract from coconut husk,” Journal of Food Science and Technology 52, 7669-7682. DOI: 10.1007/S13197-015-1905-1

Nilsuwan, K., Benjakul, S., Prodpran, T., Caba, K. d. l. (2019). “Fish gelatin monolayer and bilayer films incorporated with epigallocatechin gallate: Properties and their use as pouches for storage of chicken skin oil,” Food Hydrocolloids 89, 783-791. DOI: 10.1016/J.FOODHYD.2018.11.056

Nuthong, P., Benjakul, S., and Prodpran, T. (2009). “Effect of phenolic compounds on the properties of porcine plasma protein-based film,” Food Hydrocolloids 23(3), 736-741. DOI: 10.1016/J.FOODHYD.2008.08.003

O’Connell, J., and Fox, P. F. (1999). “Proposed mechanism for the effect of polyphenols on the heat stability of milk,” International Dairy Journal 9(8), 523-536. DOI: 10.1016/S0958-6946(99)00124-7

Ojha, H., Mishra, K., Hassan, M. I., and Chaudhury, N. K. (2012). “Spectroscopic and isothermal titration calorimetry studies of binding interaction of ferulic acid with bovine serum albumin,” Thermochimica Acta 548, 56-64. DOI: 10.1016/J.TCA.2012.08.016

Ozdal, T., Capanoglu, E., and Altay, F. (2013). “A review on protein-phenolic interactions and associated changes,” Food Research International 51(2), 954-970. DOI: 10.1016/J.FOODRES.2013.02.009

Papadopoulou, A., Green, R. J., and Frazier, R. A. (2004). “Interaction of flavonoids with bovine serum albumin:  A fluorescence quenching study,” Journal of Agricultural and Food Chemistry 53(1), 158-163. DOI: 10.1021/JF048693G

Parada, J., and Aguilera, J. M. (2007). “Food microstructure affects the bioavailability of several nutrients,” Journal of Food Science 72(2), R21-R32. DOI: 10.1111/j.1750-3841.2007.00274.x

Pessato, T. B., Carvalho N. C. d., Figueiredo D. d., Colomeu, T. C., Fernandes, L. G. R., Netto, F. M., and Zollner, R. D. L. (2019). “Complexation of whey protein with caffeic acid or (-)-epigallocatechin-3-gallate as a strategy to induce oral tolerance to whey allergenic proteins,” International Immunopharmacology 68, 115-123. DOI: 10.1016/J.INTIMP.2018.12.047

Pessato, T. B., Morais, F. P. R. d., Carvalho, N. C. d., Figueira, A. C. M., Fernandes, L. G. R., Zollner, R. d. L., and Netto, F. M. (2018). “Protein structure modification and allergenic properties of whey proteins upon interaction with tea and coffee phenolic compounds,” Journal of Functional Foods 51, 121-129. DOI: 10.1016/J.JFF.2018.10.019

Phillips, G. O., and Williams, P. A. (2011). “Introduction to food proteins,” in: Handbook of Food Proteins, G. O. Phillips and P. A. Williams (ed.) Woodhead Publishing, Sawston, United Kingdom, pp. 1-12.

Prasanna, G., and Jing, P. (2018). “Spectroscopic and molecular modelling studies on glycation modified bovine serum albumin with cyanidin-3-O-glucoside,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 204, 708-716. DOI: 10.1016/J.SAA.2018.06.103

Prigent, S. V. E., Gruppen, H., Visser, A. J. W. G., Koningsveld, G. A. v., Jong, G. A. H. d., and Voragen, A. G. J. (2003). “Effects of noncovalent interactions with 5-O-caffeoylquinic acid (chlorogenic acid) on the heat denaturation and solubility of globular proteins,” Journal of Agricultural and Food Chemistry 51(17), 5088-5095. DOI: 10.1021/JF021229W

Prigent, S. V. E., Voragen, A. G. J., Visser, A. J. W. G., Koningsveld, G. A. v., and Gruppen, H. (2007). “Covalent interactions between proteins and oxidation products of caffeoylquinic acid (chlorogenic acid),” Journal of the Science of Food and Agricultural 87(13) 2502-2510. DOI: 10.1002/JSFA.3011

Prigent, S. V. E., Voragen, A. G. J., Koningsveld, G. A. v., Baron, A., Renard, C. M. G. C., and Gruppen, H. (2009). “Interactions between globular proteins and procyanidins of different degrees of polymerization,” Journal of Dairy Science 92(12), 5843-5853. DOI: 10.3168/JDS.2009-2261

Prodpran, T., Benjakul, S., and Phatcharat S. (2012). “Effect of phenolic compounds on protein cross-linking and properties of film from fish myofibrillar protein,” International Journal of Biological Macromolecules 51(5), 774-782. DOI: 10.1016/J.IJBIOMAC.2012.07.010

Quan, T. H., and Benjakul, S. (2019). “Duck egg albumen: Physicochemical and functional properties as affected by storage and processing,” Journal of Food Science and Technology 56, 1104-1115. DOI: 10.1007/s13197-019-03669-x

Rahayu, P. P., Andriani, R. D., and Maligan, J. M. (2020). “Molecular docking studies and physicochemical properties on the interaction of xanthone with whey protein (β-lactoglobulin and α-lactalbumin),” IOP Conference Series Earth and Environmental Science 443, 1-9. DOI: 10.1088/1755-1315/443/1/012011

Rasouli, M., Abbasi, S., Azarikia, F., and Ettelaie, R. (2019). “On the heat stability of whey protein: Effect of sodium hexametaphosphate,” International Journal of Dairy Technology 73(1), 46-56. DOI: 10.1111/1471-0307.12626

Rawel, H. M., and Rohn S. (2010). “Nature of hydroxycinnamate-protein interactions,” Photochemistry Reviews 9, 93-109. DOI: 10.1007/s11101-009-9154-4

Rawel, H. M., Czajka, D., Rohn, S., and Kroll J. (2002). “Interactions of different phenolic acids and flavonoids with soy proteins,” International Journal of Biological Macromolecular 30(3-4), 137-150. DOI: 10.1016/S0141-8130(02)00016-8

Rawel, H. M., Meidtner, K., and Kroll, J. (2005). “Binding of selected phenolic compounds to proteins,” Journal of Agricultural and Food Chemistry 53(10), 4228-4235. DOI: 10.1021/jf0480290

Relkin, P., and Shukat, R. (2012). “Food protein aggregates as vitamin-matrix carriers: Impact of processing conditions,” Food Chemistry 134(4), 2141-2148. DOI: 10.1016/j.foodchem.2012.04.020

Rubanza, C. D. K., Shem, M. N., Otsyina, R., Bakengesa, S. S., Ichinohe, T., and Fujihara, T. (2005). “Polyphenolics and tannins effect on in vitro digestibility of selected Acacia species leaves,” Animal Feed Science and Technology 119(1-2), 129-142. DOI: 10.1016/j.anifeedsci.2004.12.004

Setiowati, A. D., Wijaya, W., and Meeren, P. V. d. (2020). “Whey protein-polysaccharide conjugates obtained via dry heat treatment to improve the heat stability of whey protein stabilized emulsions,” Trends in Food Science & Technology 98, 150-161. DOI: 10.1016/J.TIFS.2020.02.011

Shafaei, Z., Ghalandari, B., Vaseghi, A., Divsalar, A., Haertlé, T., Saboury, A. A., and Sawyer, L. (2017). “β-lactoglobulin: An efficient nanocarrier for advanced delivery systems,” Nanomedicine: Nanotechnology, Biological and Medicine 13(5), 1685-1692. DOI: 10.1016/J.NANO.2017.03.007

Shen, F., Niu, F., Li, J., Su, Y., Liu, Y., and Yang, Y. (2014). “Interactions between tea polyphenol and two kinds of typical egg white proteins-ovalbumin and lysozyme: Effect on the gastrointestinal digestion of both proteins in vitro,” Food Research International 59, 100-107. DOI: 10.1016/J.FOODRES.2014.01.070

Shpigelman, A., Cohen, Y., and Livney, Y. D. (2012). “Thermally-induced β-lactoglobulin–EGCG nanovehicles: Loading, stability, sensory and digestive-release study,” Food Hydrocolloids 29(1), 57-67. DOI: 10.1016/J.FOODHYD.2012.01.016

Siebert, K. J. (1999). “Effects of protein−polyphenol interactions on beverage haze, stabilization, and analysis,” Journal of Agricultural and Food Chemistry 47(2), 353-362. DOI: 10.1021/JF980703O

Staszewskim, M. v., Jagus, R. J., and Pilosof, A. M. R. (2011). “Influence of green tea polyphenols on the colloidal stability and gelation of WPC,” Food Hydrocolloids 25(5), 1077-1084. DOI: 10.1016/J.FOODHYD.2010.10.004

Staszewski, M. v., Jara, F. L., Ruiz, A. L. T. G., Jagus, R. J., Carvalho, J. E., and Pilosof, A. M. R. (2012). “Nanocomplex formation between β-lactoglobulin or caseinomacropeptide and green tea polyphenols: Impact on protein gelation and polyphenols antiproliferative activity,” Journal of Functional Foods 4(4), 800-809. DOI: 10.1016/J.JFF.2012.05.008

Stojadinovic, M., Radosavljevic, J., Ognjenovic, J., Vesic, J., Prodic, I., Stanic-Vucinic, D., and Velickovic, T. C. (2013). “Binding affinity between dietary polyphenols and β-lactoglobulin negatively correlates with the protein susceptibility to digestion and total antioxidant activity of complexes formed,” Food Chemistry 136(3-4), 1263-1271. DOI: 10.1016/J.FOODCHEM.2012.09.040

Strauss, G., and Gibson, S.M. (2004). “Plant phenolics as cross-linkers of gelatin gels and gelatin-based coacervates for use as food ingredients,” Food Hydrocolloids 18(1), 81-89. DOI: 10.1016/S0268-005X(03)00045-6

Suryaprakash, P., Kumar, R. P., and Prakash, V. (2000). “Thermodynamics of interaction of caffeic acid and quinic acid with multisubunit proteins,” International Journal of Biological Macromolecules 27(3), 219-228. DOI: 10.1016/S0141-8130(00)00119-7

Tang, L., Li, S., Bi, H., and Gao, X. (2016). “Interaction of cyanidin-3-O-glucoside with three proteins,” Food Chemistry 196, 550-559. DOI: 10.1016/J.FOODCHEM.2015.09.089

Tang, C., Tan, B., and Sun, X. (2021). “Elucidation of interaction between whey proteins and proanthocyanidins and its protective effects on proanthocyanidins during in-vitro digestion and storage,” Molecules 26(18), article no. 5468. https://www.mdpi.com/1420-3049/26/18/5468

Tantoush, Z., Stanic, D., Stojadinovic, M., Ognjenovic, J., Mihajlovic, L., Atanaskovic-Markovic, M., and Velickovic, T. C. (2011). “Digestibility and allergenicity of β-lactoglobulin following laccase-mediated cross-linking in the presence of sour cherry phenolics,” Food Chemistry 125(1), 84-91. DOI: 10.1016/J.FOODCHEM.2010.08.040

Tao, F., Xiao, C., Chen, W., Zhang, Y., Pan, J., and Jia Z. (2019). “Covalent modification of β-lactoglobulin by (-)-epigallocatechin-3-gallate results in a novel antioxidant molecule,” International Journal of Biological Macromolecules 126, 1186-1191. DOI: 10.1016/J.IJBIOMAC.2019.01.017

Temdee, W., and Benjakul, S. (2015). “Effect of phenolic compounds and bark/wood extracts oxidised by laccase on properties of cuttlefish (Sepia pharaonis) skin gelatin gel,” International Food Research Journal 22(1), 246-253.

Tokmakov, A. A., Kurotani, A., and Sato, K.-I. (2021). “Protein pI and intracellular localization,” Frontiers in Molecular Bioscience 8, article 775736. DOI: 10.3389/fmolb.2021.775736

Tsai, P. J., and She, C. H. (2006). “Significance of phenol−protein interactions in modifying the antioxidant capacity of peas,” Journal of Agricultural and Food Chemistry 54(22), 8491-8494. DOI: 10.1021/JF061475Y

Velickovic, T. D. C., and Stanic-Vucinic, D. J. (2017). “The role of dietary phenolic compounds in protein digestion and processing technologies to improve their antinutritive properties,” Comprehensive Reviews in Food Science and Food Safety 17(1), 82-103. DOI: 10.1111/1541-4337.12320

Wang, Q., Liu, W., Tian, B., Li, D., Liu, C., Jiang, B., and Feng, Z. (2020a). “Preparation and characterization of coating based on protein nanofibers and polyphenol and application for salted duck egg yolks,” Foods 9(4), 1-16. DOI: 10.3390/FOODS9040449

Wang, W.-D., Li, C., Bin, Z., Huang, Q., You, L.-J., Chen, C., Fu, X., and Liu, R.H. (2020b). “Physicochemical properties and bioactivity of whey protein isolate-inulin conjugates obtained by Maillard reaction,” International Journal of Biological Macromolecules 150, 326-335. DOI: 10.1016/J.IJBIOMAC.2020.02.086

Wang, X., Zhang, J., Lei, F., Liang, C., Yuan, F., and Gao, Y. (2014). “Covalent complexation and functional evaluation of (-)-epigallocatechin gallate and α-lactalbumin,” Food Chemistry 150, 341-347. DOI: 10.1016/J.FOODCHEM.2013.09.127

Wei, Z., Yang, W., Fan, R., Yuan, F., and Gao, Y. (2015). “Evaluation of structural and functional properties of protein–EGCG complexes and their ability of stabilizing a model β-carotene emulsion,” Food Hydrocolloids 45, 337-350. DOI: 10.1016/J.FOODHYD.2014.12.008

Wu, S., Zhang, Y., Ren, F., Qin, Y., Liu, J., Liu, J., Wang, Q., and Zhang H. (2018a). “Structure–affinity relationship of the interaction between phenolic acids and their derivatives and β-lactoglobulin and effect on antioxidant activity,” Food Chemistry 245, 613-619. DOI: 10.1016/J.FOODCHEM.2017.10.122

Wu, X., Lu, Y., Xu, H., Lin, D., He, Z., Wu, H., Liu, L., and Wang, Z. (2018b). “Reducing the allergenic capacity of β-lactoglobulin by covalent conjugation with dietary polyphenols,” Food Chemistry 256, 427-434. DOI: 10.1016/J.FOODCHEM.2018.02.158

Wu, X., Wu, H., Liu, M., Liu, Z., Xu, H., and Lai, F. (2011). “Analysis of binding interaction between (-)-epigallocatechin (EGC) and β-lactoglobulin by multi-spectroscopic method,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectrosccopy 82(1), 164-168. DOI: 10.1016/J.SAA.2011.07.028

Xiao, J., Mao, F., Yang, F., Zhao, Y., Zhang, C., and Yamamoto, K. (2011). “Interaction of dietary polyphenols with bovine milk proteins: Molecular structure–affinity relationship and influencing bioactivity aspects,” Molecular Nutrition & Food Research 55(11), 1637-1645. DOI: 10.1002/MNFR.201100280

Xiong, Y. L., and Guo, A. (2021). “Animal and plant protein oxidation: Chemical and

functional property significance,” Foods 10, 40. DOI: 10.3390/foods10010040.

Xu, H., Lu, Y., Zhang, T., Liu, K., Liu, L., He, Z., Xu, B., and Wu, X. (2019a). “Characterization of binding interactions of anthraquinones and bovine β-lactoglobulin,” Food Chemistry 281, 28-35. DOI: 10.1016/J.FOODCHEM.2018.12.077

Xu, H., Zhang, T., Lu, Y., Lin, X., Hu, X., Liu, L., He, Z., and Wu, X. (2019b). “Effect of chlorogenic acid covalent conjugation on the allergenicity, digestibility and functional properties of whey protein,” Food Chemistry 298, 1-7. DOI: 10.1016/J.FOODCHEM.2019.125024

Xu, Z., Zhao, L., Wang, Y., and Liao, X. (2019c). “Effects of high pressure processing on the interaction of α-lactalbumin and pelargonidin-3-glucoside,” Food Chemistry 285, 22-30. DOI: 10.1016/J.FOODCHEM.2019.01.129

Yan, M., Li, B., Zhao, X., and Yi, J. (2011). “Physicochemical properties of gelatin gels from walleye pollock (Theragra chalcogramma) skin cross-linked by gallic acid and rutin,” Food Hydrocolloids 25(5), 907-914. DOI: 10.1016/J.FOODHYD.2010.08.019

Yi, J., Fan, Y., Zhang, Y., and Zhao, L. (2016). “Characterization of catechin-α-lactalbumin conjugates and the improvement in β-carotene retention in an oil-in-water nanoemulsion,” Food Chem. 205, 73-80. DOI: 10.1016/J.FOODCHEM.2016.03.005

Yi, J., Zhang, Y., Liang, R., Zhong, F., and Ma, J. (2015). “Beta-carotene chemical stability in nanoemulsions was improved by stabilized with beta-lactoglobulin-catechin conjugates through free radical method,” Journal of Agricultural and Food Chemistry 63(1), 297-303. DOI: 10.1021/JF5056024

Yildirim-Elikoglu, S., and Erdem, Y. K. (2017). “Interactions between milk proteins and polyphenols: Binding mechanisms, related changes, and the future trends in the dairy industry,” Food Reviews International 34(7), 665-697. DOI: 10.1080/87559129.2017.1377225

Yin, C., Yang, L., Zhao, H., and Li, C. P. (2014). “Improvement of antioxidant activity of egg white protein by phosphorylation and conjugation of epigallocatechin gallate,” Food Research International 64, 855-863. DOI: 10.1016/J.FOODRES.2014.08.020.

You, J., Luo, Y., and Wu, J. (2014). “Conjugation of ovotransferrin with catechin shows improved antioxidant activity,” Journal of Agricultural and Food Chemistry 62(12), 2581-2587. DOI: 10.1021/JF405635Q

Zhan, F., Chen, Y., Hu, J., Youssef, M., Korin, A., Li, J., and Li, B., (2020). “Combining surface dilatational rheology and quantitative proteomics as a tool for understanding microstructures of air/water interfaces stabilized by sodium caseinate/tannic acid complex,” Food Hydrocolloids 102, 1-10. DOI: 10.1016/J.FOODHYD.2019.105627

Zhang, X., Do, M. D., Casey, P., Sulistio, A., Qiao, G. G., Lundin, L., Lillford, P., and Kosaraju, S. (2010). “Chemical cross-linking gelatin with natural phenolic compounds as studied by high-resolution NMR spectroscopy,” Biomacromolecules 11(4), 1125-1132. DOI: 10.1021/BM1001284

Zhao, X., Xu, X., and Zhou, G. (2021). “Covalent chemical modification of myofibrillar proteins to improve their gelation properties: A systematic review,” Comprehensive Rev. Food Science and Food Safety 20, 924-959. DOI: 10.1111/1541-4337.12684.

Zhao, Y., and Sun, Z. (2018). “Effects of gelatin-polyphenol and gelatin-genipin cross-linking on the structure of gelatin hydrogels,” International Journal of Food Properties 20(3), S2822-2832. DOI: 10.1080/10942912.2017.1381111

Zhong, Y., Zhao, J., Dai, T., McClements, D. J., and Liu, C. (2021). “The effect of whey protein-puerarin interactions on the formation and performance of protein hydrogels,” Food Hydrocolloids 113, 1-8. DOI: 10.1016/J.FOODHYD.2020.106444

Article submitted: April 6, 2022; Peer review completed: June 11, 2022; Revised version received: July 28, 2022; Accepted: July 29, 2022; Published: August 4, 2022.

DOI: 10.15376/biores.17.4. Tazeddinova1