Soy proteins as important food ingredients exhibit a great potential to be widely applied in food formulations, due to their good nutrition, functional properties and health effects. The knowledge ...about the structure-function relationships of these proteins is crucial for their applications, but still very scant, especially that on their molecular mechanism of emulsification. The purpose of this review is to present a comprehensive summary of the knowledge about emulsifying and interfacial properties of soy proteins, achieved during the past decades, and particularly to provide an insight in understanding the role of conformational flexibility in their emulsifying properties. The interplays between the emulsifying and interfacial properties are also elucidated. For these proteins, the conformational flexibility rather than the surface hydrophobicity is the crucial parameter determining their emulsification performance. On the other hand, evidence is fast growing to indicate that because of the insoluble nature, soy proteins are a kind of unique materials to perform as food-grade Pickering stabilizers. The knowledge about the Pickering emulsion stabilization is distinctly different from that for conventional emulsions stabilized by soy proteins. Thus, different strategies should be employed to develop soy proteins into a kind of effective emulsifiers, depending on the preference of emulsification performance or emulsion stability.
Many globular proteins are good emulsifiers or stabilizers for oil-in-water emulsions. It is generally recognized in the field that globular proteins tend to undergo a structural unfolding and ...rearrangement when adsorbed at oil-water interface, and as a result, a viscoelastic interfacial film is formed. However, more evidences are fast accumulating in recent years to show that globular proteins exhibit a great potential to perform as soft particles for stabilizing emulsions. This review mainly presents the state-of-the-art knowledge about the emulsification performance and interfacial stabilization of globular proteins, achieved in the recent several years, especially by our research group. A critical summary of current understanding about the emulsification and interfacial properties of globular proteins, as well as some limitations existing for the knowledge, is first presented. Then, the concepts, structural requirements and strategies for globular proteins as soft particles for stabilizing emulsions or high internal phase emulsions (HIPEs) are introduced in details. The effective strategies include, but are not limited to, choosing native glycated globular proteins or glycation with carbohydrates, strengthening structural stability of globular proteins by polyols (dissaccharides in particular), and pH adjustment. Finally, some advantages and limitations of globular proteins as soft particles for stabilizing emulsions or HIPEs are discussed. Due to the increasing interests from food industry and health wareness from consumers in developing safe emulsifiers, this review is of crucial importance for the understanding of the role of structural characteristics in emlusification and emulsion stabilization of globular proteins, as well as their ultilization as emulsifers/stabilizers in food industry.
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•Globular proteins exhibit a great potential to act as soft particles for stabilizing emulsions.•The concepts, structural requirements and strategies of globular proteins as soft particles are discussed.•Glycated globular proteins are demonstrated to be a kind of soft Pickering particles.•The presence of dissaccharides can transform globular proteins into effective soft particles.•The formation of ‘core-shell’ nanoparticle structure is a prerequisite for globular proteins as soft particles.
Soy proteins as an important food ingredient have been widely applied in food formulations, due to their good nutritional value, high functionalities, and health-benefiting effects. Evidences have ...been fast accumulating to indicate that soy proteins are a kind of excellent building materials to be fabricated into a variety of nanostructured delivery systems for food bioactive ingredients. This review mainly presents the state-of-the-art knowledge about the fabrication of different kinds of nanostructures of soy proteins, as well as their applications to perform as nanocarriers for bioactives, achieved during the past decade. The composition, structure and physicochemical properties of soy proteins (including glycinin, β-conglycinin, and soy protein isolate) are first summarized. Then, the main strategies and techniques to fabricate a variety of nanostructured soy proteins are reviewed, including heat-induced aggregation, complexation with polysaccharides, emulsification-evaporatioin, desolvation/solvent displacement, crosslinking, self-assembly, electrospraying, nanoemulsions and interfacially nanostructured emulsions. Lastly, the feasibility of these nanostructured soy proteins (especially nanoparticles) to peroform as effective nanocarriers or delivery systems for bioactives are discussed. Due to the fast increasing interest of the food industry and consumer health awareness for the incorporation of soy proteins in functional food formulations, this review is of importance for guiding the development of novel ‘dual-function’ nanostructured soy protein-bioactive formulations.
Nanostructured Soy Proteins: Fabrication and Applications as Delivery Systems for Bioactives. Display omitted
•Soy proteins exhibit a great potential to be fabricated into a variety of nanostructures.•Soy protein nanoparticles can be fabricated via a number of strategies.•Nanostructured soy proteins can perform as effective delivery systems for bioactives.•Novel ‘dual-function’ nanostructured soy protein-bioactive formulations can be produced.•More efforts are still needed to demonstrate the effectiveness of these delivery systems.
The high incidence of chronic diseases such as cardiovascular diseases, diabetes and cancer has become one of the most challenging issues to deal with for modern society. To date, numerous ...nutraceuticals or bioactives from diets have been demonstrated to produce a variety of health-benefiting effects on many diseases. However, most of these bioactives are poorly soluble and have low bioaccessibility/bioavailability, which greatly limits their applications in food or pharmaceutical formulations. This review mainly presents a facile and effective nanoencapsulation strategy to improve water dispersibility, stability and even bioactivities of poorly soluble nutraceuticals (with an emphasis on curcumin, a typical poorly soluble nutraceutical with a lot of health effects), through nanocomplexation with food proteins. In the first part, the advances in the understanding of the interaction between proteins and curcumin, including techniques to monitor the interaction, and parameters describing the interaction between proteins and curcumin (e.g., nature and mode of interactive forces, number of binding sites and location on the surface of proteins), are comprehensively reviewed. Then, the potential and effectiveness of using nanocomplexes with proteins as nanocarriers for improving water solubility, stability and bioactivities of curcumin are critically summarized. The strategies to improve the nanocomplexation between proteins and curcumin are highlighted. Lastly, the advantages and limitations of the nanoencapsulation of curcumin by the nanocomplexation with proteins, as well as some technical considerations for spray-drying the nanocomplexes, are simply introduced. With the increasing need for the development of natural and safe functional foods for human health considerations, this review would be of vital importance for providing insights in using this nanoencapsulation to facilitate the incorporation of poorly soluble nutraceuticals in functional foods formulations.
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•Binding of curcumin to proteins is generally via hydrophobic interactions.•Curcumin complexes with native proteins tend to have a 1:1 M ratio.•Nanocomplexation with proteins is an effective and facile nanoencapsulation for curcumin.•The nanocomplexation great improves water solubility, stability and bioactivities of curcumin.•The potential of soy proteins to act as nanocarriers for curcumin is highlighted.
Incorporation of hydrophobic and poorly soluble nutraceuticals into food formulations is among the great challenges in food science and pharmaceutical fields. One effective strategy to meet this ...challenge is to develop a kind of food-compatible nanovehicles for improving water solubility, stability, bioavailability and bioactivities of these nutraceuticals. Many food protein-based nano-architectures, e.g., nanoparticles, nano-complexes, nanogels, nano-micelles, nanofibers or nanotubes, have been demonstrated to perform as outstanding nanovehicles in this regard. They are not only nutritional/digestible, safe, and easy to prepare and handle, but also have high encapsulation performance and nutraceutical loading capacity. In some cases, the encapsulation in these nanovehicles can impart an intestine-targeted and controlled delivery function to encapsulated nutraceuticals. In this paper, the assembly of milk and soy proteins into a variety of nano-architectures, as potential nanovehicles for hydrophobic nutraceuticals is critically reviewed. The strategies to trigger the assembly, or disassembly/reassembly of naturally occurring nano-architectures (e.g., native soy oligomeric globulins and casein micelles), denatured and aggregated proteins (e.g., soy protein isolate and whey protein isolate), and monomeric globular proteins (e.g., β-lactoglobulin) are highlighted. The general principles of protein self-assembly are also discussed. Due to the fast increasing interests for the incorporation of hydrophobic nutraceuticals in many novel food formulations, this review is of relevance for providing a state-of-art knowledge about the strategies and approaches to develop food protein-based nano-architectures as effective nanovehicles for nutraceuticals.
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•Food proteins exhibit a great potential in nanoencapsulation of nutraceuticals.•General principles of protein self-assembly are presented.•Soy and milk proteins can form versatile nano-architectures via different strategies.•Strategies to trigger the assembly of soy and milk proteins into nano-architectures are highlighted.•Natural architectures (casein micelles and soy globulins) can perform as nanovehicles for nutraceuticals.
In recent years, there have been increasing interests in developing food-grade Pickering stabilizers, due to their potential applications in formulations of novel functional foods. The present work ...was to investigate the potential of soy proteins to be developed into a kind of Pickering-like stabilizer for oil-in-water emulsions. The nanoparticle aggregates of soy protein isolate (SPI) were formed by sequential treatments of heating at 95 °C for 15 min and then electrostatic screening with NaCl addition. The particle size and microstructure of these aggregates were characterized using dynamic light scattering and atomic force microscopy, indicating that the fabricated nanoparticle aggregates were ∼100 nm in size with more surface hydrophobic nature (relative to unheated SPI). The influence of particle concentration (c; 0.5–6.0%, w/w) and increasing oil fraction (ϕ; in the range 0.2–0.6) on the droplet size and coalescence and/or creaming stability of the emulsions stabilized by these nanoparticle aggregates was investigated. The results showed that, at ϕ = 0.2, increasing the c resulted in a progressive but slight decrease in droplet size, and improved the stability against coalescence and creaming; at a specific c, the creaming stability was progressively increased by increasing the ϕ, with better improvement observed at a higher c (e.g., 6.0% vs 2.0%). The improvement of creaming stability was largely associated with the formation of a gel-like network that could entrap the oil droplets within the network. The observations are generally consistent with those observed for the conventional Pickering emulsions, confirming that soy proteins could be applied as a kind of effective Pickering-like stabilizer. The finding may have important implications for the design and fabrication of protein-based emulsion formulations, and even for the development of soy protein products with some unique functions. To the authors’ knowledge, this is the first work to report that heat-induced soy protein aggregates exhibit a good potential to act as Pickering-type stabilizers.
Use of protein-based nanovehicles has been well recognized to be one of the most effective strategies to improve water dispersibility, stability and bioavailability of nutraceuticals or bioactive ...ingredients. Thanks to their health-benefiting effects and unique assembly behavior, soy proteins seem to be the perfect food proteins for fabricating nanovehicles in this regard. This review presents the state-of-art knowledge about the assembly of soy proteins into nano-architectures, e. g., nanoparticles, nanocomplexes or nanogels, induced by different physicochemical strategies and approaches. The strategies to trigger the assembly of soy proteins into a variety of nano-architectures are highlighted and critically reviewed. Such strategies include heating, enzymatic hydrolysis, pH shift, urea or ethanol treatment, reduction, and static high pressure treatment. The self-assembly behavior of soy proteins (native or denatured) is also reviewed. Besides the assembly of proteins alone, soy proteins can co-assemble with polysaccharides to form versatile nano-architectures, through different processes, e.g., heating or ultrasonication. Finally, recent progress in the development of assembled soy protein nano-architectures as nanovehicles for hydrophobic nutraceuticals is briefly summarized. With the fast increasing health awareness for natural and safe functional foods, this review is of crucial relevance for providing an important strategy to develop a kind of novel soy protein-based functional foods with dual-function health effects from soy proteins and nutraceuticals.
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•Soy proteins exhibit a great potential in the nanoencapsulation of nutraceuticals.•Self-assembly of soy proteins are simply presented.•Soy proteins can form versatile nano-architectures via disassembly and reassembly strategies.•Strategies to trigger the assembly of soy proteins into nano-architectures are highlighted.•Soy protein based nano-architectures as nanovehicles for nutraceuticals are reviewed.
The development of protein-based nanovehicles to improve water solubility, stability and bioavailability of hydrophobic or poorly soluble nutraceuticals has become a subject of fast increasing ...interest in the field. This review mainly presents the state-of-art knowledge about the utilization of naturally occurring nanostructured protein architectures (casein micelles, ferritin and legume oligomeric globulins) as nanovehicles for hydrophobic nutraceuticals or drugs, through a disassembly and reassembly strategy. First, the composition and structural features of these three naturally occurring architectures are briefly summarized. Then, many strategies and techniques to mediate the disassembly and reassembly of these naturally occurring architectures are comprehensively reviewed, including pH-, urea-, alcohol-, high pressure -, and heat-mediated disassembly and reassembly (or dissociation and reassociation). Last, reassembled casein micelles, ferritin (or apoferritin) and legume oligomeric protein nanoparticles are demonstrated to perform as outstanding nanovehicles for improving water dispersion, stability and bioactivities of many nutraceuticals or drugs. Due to the rapidly increasing consumer interests for health-benefiting foods, this review is of importance for the development of a kind of outstanding nanovehicles for nutraceuticals with a great potential to be applied in functional foods or drug formulations.
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•Many naturally occurring protein architectures can act as nanovehicles for nutraceuticals or drugs.•Strategies for disassembly and reassembly of protein architectures are critically reviewed.•Reassembled protein architectures or nanoparticles as nanovehicles for nutraceuticals are reviewed.•Casein micelles are the widely investigated protein architectures to act as nanovehicles.•Reassembled legume globulin nanoparticles show a promising potential to act as nanovehicles.
The interfacial and emulsifying properties of soy protein isolate nanoparticles formed by combined treatments of heating and electrostatic screening, as affected by variation of the protein ...concentration (c) and emulsification process, were investigated. These nanoparticles (with a z-average diameter of 103 nm at c = 0.1%, w/v) tended to aggregate at higher c values, and their internal structure was mainly maintained by hydrophobic interactions and disulfide bondings. In general, increasing c progressively favored diffusion and/or adsorption at the interface and formation of finer emulsions; increasing the energy input level of emulsification improved the emulsification efficiency and extent of droplet flocculation, as well as the emulsion coalescence and creaming stability. The rheological and creaming behavior of these emulsions was predominately determined by the amount of proteins adsorbed at the interface. The results confirmed that these nanoparticles can formulate Pickering emulsions with properties tailored by selecting c and the emulsification process.
Nanoencapsulation of hydrophobic nutraceuticals with food ingredients has become one of topical research subjects in food science and pharmaceutical fields. To fabricate food protein-based ...nano-architectures as nanovehicles is one of effective strategies or approaches to improve water solubility, stability, bioavailability and bioactivities of poorly soluble or hydrophobic nutraceuticals. Milk proteins or their components exhibit a great potential to assemble or co-assemble with other components into a variety of nano-architectures (e.g., nano-micelles, nanocomplexes, nanogels, or nanoparticles) as potential nanovehicles for encapsulation and delivery of nutraceuticals. This article provides a comprehensive review about the state-of-art knowledge in utilizing milk proteins to assemble or co-assemble into a variety of nano-architectures as promising encapsulation and delivery nano-systems for hydrophobic nutraceuticals. First, a brief summary about composition, structure and physicochemical properties of milk proteins, especially caseins (or casein micelles) and whey proteins, is presented. Then, the disassembly and reassembly behavior of caseins or whey proteins into nano-architectures is critically reviewed. For caseins, casein micelles can be dissociated and further re-associated into novel micelles, through pH- or high hydrostatic pressure-mediated disassembly and reassembly strategy, or can be directly formed from caseinates through a reassembly process. In contrast, the assembly of whey protein into nano-architectures usually needs a structural unfolding and subsequent aggregation process, which can be induced by heating, enzymatic hydrolysis, high hydrostatic pressure and ethanol treatments. Third, the co-assembly of milk proteins with other components into nano-architectures is also summarized. Last, the potential and effectiveness of assembled milk protein nano-architectures, including reassembled casein micelles, thermally induced whey protein nano-aggregates, α-lactalbumin nanotubes or nanospheres, co-assembled milk protein-polysaccharide nanocomplexes or nanoparticles, as nanovehicles for nutraceuticals (especially those hydrophobic) are comprehensively reviewed. Due to the fact that milk proteins are an important part of diets for human nutrition and health, the review is of crucial importance not only for the development of novel milk protein-based functional foods enriched with hydrophobic nutraceuticals, but also for providing the newest knowledge in the utilization of food protein assembly behavior in the nanoencapsulation of nutraceuticals.
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•Milk proteins are excellent starting materials to build nutraceutical nano-architectures.•Casein micelles are natural nanovehicles for nutraceuticals.•Caseins can be utilized to form nanovehicles through different disassembly and reassembly strategies.•Whey proteins can be assembled into versatile nano-architectures through different strategies.•Milk protein based nano-architectures as nanovehicles for nutraceuticals are revieweds.
