Protein Isolate Nanoparticles Research Articles

Fabrication and characterization of novel TGase-mediated glycosylated whey protein isolate nanoparticles for curcumin delivery

The aim of this study was to fabricate novel transglutaminase (TGase)-mediated glycosylated whey protein isolate (WPI) nanoparticles for the encapsulation and delivery of curcumin. The influences of glycosylation on the physiochemical properties, stability, bioavailability, and antioxidant properties of WPI nanoparticles loaded with curcumin were investigated. Composite nanoparticles exhibited uniform distribution and small particle sizes. The main driving forces for the formation of curcumin nanoparticles were electrostatic interactions, hydrogen bonding, and hydrophobic interactions. The encapsulation and loading efficiency of curcumin after TGase-type glycosylation were significantly increased in comparison to WPI-curcumin nanoparticles. Glycosylated WPI-curcumin nanoparticles had stronger antioxidant properties and stability to resist external environmental changes than WPI-curcumin nanoparticles. In addition, glycosylated WPI-curcumin nanoparticles showed a controlled release and enhanced curcumin bioavailability in vitro gastrointestinal digestion. This study provides novel insights for self-assembled glycosylated protein nanoparticles as delivery systems for protecting hydrophobic nutrients.

Preparation of pumpkin seed protein isolate nanoparticles by heat-assisted pH-shifting: Enhanced emulsification performance and dispersibility

A food-grade Pickering emulsifier was fabricated using heat-assisted pH-shifting (HP) method for enhancing the emulsion stability. The emulsification performance of the modified pumpkin seed protein isolate (PSPI) nanoparticles was initially tested. The results showed that the modified PSPI had substantially improved emulsifying capacity, with the internal oil phase volume fraction reaching up to 80%, and the emulsion remaining stable after centrifugation at 10,000 g for 60 min and 30 days of storage. The data from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), UV–visible, intrinsic fluorescence and fourier transform infrared spectroscopy (FTIR) indicated that the primary, secondary and tertiary structures of PSPI were disrupted, resulting in changes in interfacial tension, wettability, particle size, and dispersibility of the protein, which promoted the adsorption of modified PSPI nanoparticles to the surface of oil droplets and improved the emulsion stability. Overall, the HP modified PSPI is a promising Pickering emulsifier for various applications.

Preparation and characterization of vitamin E/calcium/soy protein isolate nanoparticles for soybean milk beverage fortification.

Soybean milk is a rich plant-based source of protein, and phenolic compounds. This study compared the nutritional value of soybean milk, flour, soy protein isolate (SPI) and evaluated the impact of prepared vitamin E/calcium salt/soy protein isolate nanoparticles (ECSPI-NPs) on fortification of developed soybean milk formulations. Results indicated that soybean flour protein content was 40.50 g/100 g, that fulfills 81% of the daily requirement (DV%), the unsaturated fatty acids (USFs), oleic and linoleic content was 21.98 and 56.7%, respectively, of total fatty acids content. In soybean milk, essential amino acids, threonine, leucine, lysine achieved 92.70, 90.81, 77.42% of amino acid scores (AAS) requirement values respectively. Ferulic acid was the main phenolic compound in soybean flour, milk and SPI (508.74, 13.28, 491.78 µg/g). Due to the moisture content of soybean milk (88.50%) against (7.10%) in soybean flour, the latest showed higher nutrients concentrations. The prepared calcium (20 mM/10 g SPI) and vitamin E (100 mg/g SPI) nanoparticles (ECSPI-NPs) exhibited that they were effectively synthesized under transmission electron microscope (TEM), stability in the zeta sizer analysis and safety up to IC50 value (202 ug/mL) on vero cell line. ECSPI-NPs fortification (NECM) enhanced significantly phenolic content (149.49 mg/mL), taste (6.10), texture (6.70) and consumer overall acceptance (6.54). Obtained results encourage the application of the prepared ECSPI-NPs for further functional foods applications.

Ultrasonic enhancement of structural and emulsifying properties of heat-treated soy protein isolate nanoparticles to fabricate flaxseed-derived diglyceride-based pickering emulsions

Flaxseed-derived diglyceride (DAG)-based Pickering emulsions were fabricated using soy protein isolate (SPI) nanoparticles as stabilizer. The SPI nanoparticles were prepared under the combined action of heating and ultrasound treatment. The SPI nanoparticles exposed to 600 W power exhibited the smallest particle size (133.36 nm) and zeta potential (-34.77 mV). Ultrasonic treatment did not significantly impact the polypeptide chain's primary structure but induced changes in the secondary structure. The Pickering emulsions stabilized with ultrasound-treated SPI nanoparticles showed smaller particle size, lower zeta potential, and improved emulsifying properties. Notably, at 450 W power, these emulsions showed a higher solid–liquid balance, reduced mean square displacement, backscattering fluctuations, and turbiscan stability index. Besides, they displayed a more compact microstructure with smaller droplets. In conclusion, SPI subjected to heating and 450 W ultrasound power resulted in the fabrication of DAG-based Pickering emulsions with enhanced microstructure and stability.

Comparative study on encapsulation of four different flavonoids into pea protein isolate nanoparticles: The impact of glycosylation

In this study, aglycone-type flavonoids (hesperitin and naringenin) and glycoside-type flavonoids (hesperidin and naringin) were encapsulated into pea protein isolate (PPI) nanoparticles by the pH-shifted method. The effect of glycosylation of flavonoids on their encapsulation efficiency in PPI carrier and their interaction with carrier molecules was explored by molecular docking along with other traditional experiments. The results showed that all flavonoids were well encapsulated in PPI nanoparticles, and hydrophobic interactions and hydrogen bonds were the important driving forces contributing to the formation of flavonoids-loaded PPI nanoparticles. However, flavonoid aglycone molecules encapsulated into nanoparticles were more than their glycoside counterparts, and flavonoid aglycones preferred to reduce fluorescence intensity and storage stability of PPI nanoparticles compared with their glycosides. Additionally, flavonoid aglycones formed less hydrogen bonds with protein compared with their corresponding glycosides. Altogether, this study can be meaningful for the selection of flavonoids more suitable for encapsulation into delivery carriers.

General liquid vegetable oil structuring via high internal phase Pickering emulsion stabilized by soy protein isolate nanoparticles

Oil structuring has attracted immense interest in the last decades because it can transform liquid oils into elastic semi-solids, which has been widely used in material science, pharmaceutical industry, and food processing. However, the facile conversion of liquid vegetable oils into soft matters without changing their intrinsic nature is challenging. Here we report a general approach for structuring liquid vegetable oils by a high internal phase Pickering emulsion (HIPPE) stabilized by edible soy protein isolate (SPI) nanoparticles. SPI nanoparticles with moderate amphipathy (θ = 90.7°) and size (∼187 nm) were obtained via the heat-induced aggregation of native SPI. These SPI nanoparticles possessed excellent interfacial activity and emulsion stabilization ability and thus were suitable for preparing edible HIPPEs from diverse liquid vegetable oils. The effect of internal volume fraction (ϕ) and particle concentration, stability, and rheology of Pickering emulsions were studied. Particularly, the role of intrinsic surfactants (e.g., lecithin) in vegetable oils on the interfacial and macro rheology of the system was highlighted. Compared with native SPI, SPI nanoparticles endowed the HIPPEs with improved stability (>14 days), high interfacial pressure (>2 mN/m), and high elastic modulus (>900 Pa). Moreover, the HIPPEs stabilized by SPI nanoparticles exhibited a good ability to structure various vegetable oils, depending on oil types and ϕ. We envisage that this biomass-mediated HIPPE system provides a promising strategy to structure various liquid vegetable oils, significantly facilitating sustainable development.

Modulation of pea protein isolate nanoparticles by interaction with OSA-corn starch: Enhancing the stability of the constructed Pickering emulsions

The impact of particle concentration (0.5–2.5%) on the stability of Pickering emulsions was investigated in this work. Pickering emulsion was prepared using pea protein isolate (PPI)/octenyl succinic anhydrate corn starch (OSA-CS) composite nanoparticles (PPI/OSA-CS) as stabilizers. PPI/OSA-CS was prepared with pH adjustment and ultrasonic treatment, and the particle size was 100.05 ± 0.46 nm. The formation of PPI/OSA-CS through hydrophobic interaction and hydrogen bond was confirmed by Fourier transform infrared spectroscopy, intrinsic fluorescence spectroscopy and dissociation analysis. The results indicated that the emulsion stabilized with composite nanoparticles at 1.5% particle concentration had smaller particle size and better stability than at other concentrations. This could be attributed to the presence of sufficient composite nanoparticles wrapped around the surface of oil droplets. At high temperature (100 °C) and high ionic strength (500 mM), the emulsion remained stable. These results provide a potential method for preparing a novel and stable Pickering emulsion, which could have important applications in various fields.

Structure and characterization of Tremella fuciformis polysaccharides/whey protein isolate nanoparticles for sustained release of curcumin.

Whey protein isolate (WPI) nanoparticles can be used in a strategy to improve the bioavailability of curcumin (CUR) although they are generally not stable. Previous studies have indicated that Tremella fuciformis polysaccharides (TFPs) can increase the stability of WPI. This work investigated systematically the characterization and structure of TFP/WPI nanoparticles with differing CUR content. The highest encapsulation efficiency of CUR was 98.8% and the highest loading content was 47.88%. The TFP-WPI-CUR with 20 mg mL-1 of CUR had the largest particle size (653.67 ± 21.50 nm) and lowest zeta potential (-38.97 ± 2.51 mV), and the capacity to retain stability across a variety of salt ion and pH conditions for 21 days. According to the findings of the structural analysis, the addition of TFPs and CUR rendered the structure of WPI amorphous, and the β-sheet was reduced. Finally, in vitro release indicated that the TFP-WPI-CUR combination could regulate the sustained release behavior of CUR. In summary, TFP-WPI nanoparticles can be used as carriers for the delivery of CUR, and can expand applications of CUR in the functional food, dietary supplement, pharmaceutical, and beverage industries. © 2023 Society of Chemical Industry.

Enhanced encapsulation of lutein using soy protein isolate nanoparticles prepared by pulsed electric field and pH shifting treatment.

In this study, soy protein isolate (SPI) was modified by a pulsed electric field (PEF) combined with pH shifting treatment (10kV/cm, pH 11) to prepare SPI nanoparticles (PSPI11) for efficient loading of lutein. The results showed that when the mass ratio of SPI to lutein was 25:1, the encapsulation efficiency of lutein in PSPI11 increased from 54% to 77%, and the loading capacity increased by 41% compared to the original SPI. The formed SPI-lutein composite nanoparticles (PSPI11-LUTNPs) had smaller, more homogeneous sizes and larger negative charges than SPI7-LUTNPs. The combined treatment favored the unfolding of the SPI structure and could expose its interior hydrophobic groups to bind with lutein. Nanocomplexation with SPIs significantly improved the solubility and stability of lutein, with PSPI11 showing the greatest improvement. As a result, PEF combined with pH shifting pretreatment is an effective method for developing SPI nanoparticles loaded and protected with lutein.

Hydroxypropyl methyl cellulose/soybean protein isolate nanoparticles incorporated broccoli leaf polyphenol to effectively improve the stability of Pickering emulsions

This study prepared SPI-Pol-HPMC (SPH) nanoparticles from soybean protein isolate (SPI), hydroxypropyl methyl cellulose (HPMC), and broccoli leaf polyphenol (Pol) and used them as a stabilizer for the Pickering emulsion. The SPH (2:1) nanoparticles have the best ability to encapsulate broccoli leaf polyphenols, with uniform particle size distribution, and a more dense and stable structure. The chemical and hydrogen bonding forces between the SPH nanoparticle components were enhanced. Additionally, the 1.5 % SPH nanoparticle-stabilized emulsions exhibited good physical stability, manifesting as small particle droplets with good rheological properties and uniform dispersion. The volume fraction of the emulsified phase of the 1.5 % SPH nanoparticle-stabilized emulsions was the greatest after 21 days of storage. Interestingly, SPH nanoparticles also improved the oxidative stability of the emulsions, as evidenced through their lower peroxide values and thiobarbituric acid active substances. The aforementioned results suggest that SPH nanoparticles may be used as food-grade emulsifiers that stabilize emulsions and inhibit their lipid oxidation.

Development and Characterization of Pickering Emulsion Stabilized by Walnut Protein Isolate Nanoparticles.

This study was conducted to prepare walnut protein isolate nanoparticles (nano-WalPI) by pH-cycling, combined with the ultrasound method, to investigate the impact of various nano-WalPI concentrations (0.5~2.5%) and oil volume fractions (20~70%) on the stability of Pickering emulsion, and to improve the comprehensive utilization of walnut residue. The nano-WalPI was uniform in size (average size of 108 nm) with good emulsification properties (emulsifying activity index and stability index of 32.79 m2/g and 1423.94 min, respectively), and it could form a stable O/W-type Pickering emulsion. When the nano-WalPI concentration was 2.0% and the oil volume fraction was 60%, the best stability of Pickering emulsions was achieved with an average size of 3.33 μm, and an elastic weak gel network structure with good thermal stability and storage stability was formed. In addition, the emulsion creaming index value of the Pickering emulsion was 4.67% after 15 days of storage. This study provides unique ideas and a practical framework for the development and application of stabilizers for food-grade Pickering emulsions.

Effect of soy protein isolate nanoparticles loaded with litsea cubeba essential oil on performance of lentinan edible films

Environmental issues caused by plastic packaging materials have gotten increasingly severe, and substantial research has been conducted on environmentally friendly active packaging materials. In this study, the Litsea cubeba essential oil loaded soy protein isolate nanoparticles (LSNPs) with appropriate particle size, high storage stability and salt solution stability were fabricated. The LSNPs with the highest encapsulation efficiency of 81.76 % were added into the lentinan edible film. The microstructures of the films were observed by scanning electron microscopy. The physical properties of the films were measured. The results show that the lentinan film with LSNPs in the volume ratio of 4:1 (LF-4) had the highest elongation at break of 196 %, the lowest oxygen permeability of 12 meq/kg, and good tensile strength, water vapor barrier property, antibacterial property, oxidation resistance and thermal stability. The study suggested that LF-4 film could inhibit the growth of bacteria and delay the oxidation of lipid and protein on beef surface for 7 d.

4D printing system stimulated by curcumin/whey protein isolate nanoparticles: A comparative study of sensitive color change and post-processing

In order to provide a more reliable curcumin stabilization scheme and efficient post-treatment process in food 4D printing system, this study innovatively introduced nano-embedding technology and catalytic infrared drying (CID) method to develop interesting color-changing materials for 4D printing based on thermal response stimuli. Firstly, curcumin (C) was encapsulated into whey protein isolate (WPI) to form nanoparticles (C-WPI-NPs), which were further added to potato starch-xanthan gum base to fabricate printing ink. The effects of C-WPI-NPs addition on the rheological properties, moisture distribution, and FTIR spectra of printing ink were investigated. It was demonstrated that the addition of C-WPI-NPs increase water-holding capacity and viscosity of the printing ink, and formation of a dense gel network while reducing water molecule movement. This resulted in excellent elastic solid-like behavior and mechanical strength against compression deformation of the printing ink. Subsequently, the effects of three drying post-treatment methods were compared, including catalytic infrared drying (CID), microwave drying (MD) and hot air drying (HAD). Compared with MD and HAD, CID showed a more uniform color change. The retention rate of curcumin under CID treatment reached 62.17%, which avoiding significant degradation of nutrients. Moreover, CID also showed great advantages in antioxidant capacity. The scavenging rate of DPPH radical was 52.69%, which was much higher than that of HAD (38.99%) and MD (36.04%). In addition, the appearance of the printed product was better preserved, and the dimensional offset rate was only 7.64%. • Curcumin/whey protein isolate nanoparticles (C-WPI-NPs) are fabricated successfully. • The 3D printing ink show preferable printability after addition of C-WPI-NPs. • The color change is achieved by heating the 3D printing product with C-WPI-NPs. • Catalytic infrared drying (CID) technology exhibit excellent post-treatment effects.

Functional, structural properties and interaction mechanism of soy protein isolate nanoparticles modified by high-performance protein-glutaminase

Investigating the changes in the structural and functional properties of soy protein isolate (SPI) modified by high-performance protein-glutaminase (PG) and understanding their interactions are crucial for the application of SPI nanoparticles. Herein, the thermal stability and activity of PG were evolved by computer-assisted rational design strategy, generating the best variant Z15 (N16M/N20L/Q21H/K48R/S81E/T113E) with a 4.65-fold improved activity (75.57 U/mg) and increased thermal stability (ΔTm = 4.6 °C), one of the best performing PG. SPI treated with Z15 showed better solubility, foaming, and emulsifying properties than the wild type PG-deamidation, which were increased by 1.25-fold, 45.45%, and 38.95%, respectively. Furthermore, SPI treated with Z15 exhibited lower hardness and higher cohesiveness. By systematically analyzing the structural characteristics, SPI nanoparticles possessed a coarse, loose, and porous microstructure. Molecular dynamics simulations suggested that the Glu81 and Glu113 residues of Z15 contributed the most to the stabilization interaction in β-conglycinin-Z15 complexes. These results could provide theoretical guidance for the potential application of SPI nanoparticles in sustainable green plant-based foods industries.

Formation mechanism and functional properties of walnut protein isolate and soy protein isolate nanoparticles using the pH-cycle technology.

Walnut protein isolate (WPI) is a nutritious protein with poor solubility, which severely limits its application. In this study, composite nanoparticles were prepared from WPI and soy protein isolate (SPI) using the pH-cycle technology. The WPI solubility increased from 12.64 to 88.53% with a WPI: SPI ratio increased from 1: 0.01 to 1: 1. Morphological and structural analyses illustrated that interaction forces with hydrogen bonding as the main effect jointly drive the binding of WPI to SPI and that protein co-folding occurs during the neutralization process, resulting in a hydrophilic rigid structure. In addition, the interfacial characterization showed that the composite nanoparticle with a large surface charge enhanced the affinity with water molecules, prevented protein aggregation, and protected the new hydrophilic structure from damage. All these parameters helped to maintain the stability of the composite nanoparticles in a neutral environment. Amino acid analysis, emulsification capacity, foaming, and stability analysis showed that the prepared WPI-based nanoparticles exhibited good nutritional and functional properties. Overall, this study could provide a technical reference for the value-added use of WPI and an alternative strategy for delivering natural food ingredients.

Pickering high internal phase emulsions with excellent UV protection property stabilized by Spirulina protein isolate nanoparticles

Herein, we reported the use of natural, renewable, and food-grade Spirulina protein isolate nanoparticles (SPI NPs) as effective particle stabilizers for Pickering high internal phase emulsions (Pickering-HIPEs). SPI NPs were prepared using a straightforward antisolvent technique and characterized using dynamic light scattering (DLS), and zeta potential measurement as well as scanning electron microscopy (SEM). SPI NPs were afterward used as sole stabilizers to prepare the oil-in-water (O/W) HIPEs, the effects of oil content, particle concentration, and pH of aqueous phase on the microstructure, stability, and rheological behaviors of the resulting Pickering-HIPEs were investigated. The Pickering-HIPEs generated showed a self-supporting gel network, a high oil content (up to 85 vol%), and extraordinary storage stability after prolonged storage and UV exposure. Concurrently, the Pickering-HIPEs provided good UV protection for a variety of photosensitive compounds, including β-carotene, vitamin E, and limonene. These findings would not only advance the development of biocompatible particle stabilizers for Pickering-HIPEs in cosmetic, food, and pharmaceutical industries, but they would also provide a guidance for the protection of photosensitive compounds.

Fabrication and Characterization of Chitosan-Pea Protein Isolate Nanoparticles.

Chitosan (CS) and pea protein isolate (PPI) were used as raw materials to prepare nanoparticles. The structures and functional properties of the nanoparticles with three ratios (1:1, 1:2 1:3, CS:PPI) were evaluated. The particle sizes of chitosan–pea protein isolate (CS–PPI) nanoparticles with the ratios of 1:1, 1:2, and 1:3 were 802.95 ± 71.94, 807.10 ± 86.22, and 767.75 ± 110.10 nm, respectively, and there were no significant differences. Through the analysis of turbidity, endogenous fluorescence spectroscopy and Fourier transform infrared spectroscopy, the interaction between CS and PPI was mainly caused by electrostatic mutual attraction and hydrogen bonding. In terms of interface properties, the contact angles of nanoparticles with the ratio of 1:1, 1:2, and 1:3 were 119.2°, 112.3°, and 107.0°, respectively. The emulsifying activity (EAI) of the nanoparticles was related to the proportion of protein. The nanoparticle with the ratio of 1:1 had the highest potential and the best thermal stability. From the observation of their morphology by transmission electron microscopy, it could be seen that the nanoparticles with a ratio of 1:3 were the closest to spherical. This study provides a theoretical basis for the design of CS–PPI nanoparticles and their applications in promoting emulsion stabilization and the delivery of active substances using emulsions.

OSA-linear dextrin enhances the compactness of pea protein isolate nanoparticles: Increase of high internal phase emulsions stability

The pea protein isolate nanoparticles/octenyl succinic anhydride linear dextrin (PPINs/OSA-LD) composite particles were fabricated by heating at acidic condition. Heating treatment not only made OSA-LD dissolve, but also promoted the hydrophobic interactions between PPINs and OSA-LD. With the increase of OSA-LD content, the average diameter of composite particles decreased due to the avoidance of hydrophobic aggregation between PPINs during heating, and the composite particles became more compact and regular. The high internal phase emulsions (HIPEs) stabilized by composite particles exhibited smaller droplet size, higher viscosity and modulus attributing to the formation of denser interfacial layer. The results of low field nuclear magnetic resonance proved that the HIPEs stabilized by composite particles showed more uniform distribution of water and oil. This work provided a facile method to fabricate composite particles, which had excellent capacity to stabilize the HIPEs.

Emulsions co-stabilized by soy protein nanoparticles and tea saponin: Physical stability, rheological properties, oxidative stability, and lipid digestion

Herein, the effects of the concentration (0.1%–1.0%, w/v) and addition sequence of tea saponin (TS) on the physical stability, oxidative stability, rheological properties, and in vitro digestion of the emulsions stabilized by heat-induced soy protein isolate nanoparticles (SPs) were investigated. The results revealed that the concentration and addition sequence of TS have significant impact on the microstructure, stability, rheological properties, and in vitro digestion of the emulsions. TS was shown to not only fill the interfacial gaps but also adsorb on the particle surfaces, contributing to interfacial wettability. With increasing TS concentration, interfacial tension decay is clearly observed. Further, TS endows the droplets with electrostatic repulsion and steric resistance, preventing their flocculation, coalescence, and oxidation. Finally, in vitro digestion experiments demonstrated that the presence of TS delayed the lipid digestion of the emulsions.

Nanoencapsulation of essential oils from industrial hemp (Cannabis sativa L.) by-products into alfalfa protein nanoparticles

Essential oils of industrial hemp (Cannabis sativa L.) by-products (HBEO) were characterized by gas chromatography-mass spectrometry (GC–MS); then, encapsulated in alfalfa protein isolate nanoparticles (API-NPs) as a novel nanocarrier. A desirable retention (45.5–63.4%) of HBEO within API-NPs was confirmed. These nanoparticles exhibited a shrunk and globular shape with a size range of 156.9–325.9 nm as indicated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Furthermore, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermal analyses corroborated that HBEO was successfully encapsulated within API NPs in an amorphous form without specific chemical interaction with the carrier matrix. The antioxidant activity of loaded HBEO into API-NPs was higher than free HBEO implying that encapsulation of HBEO in API-NPs was an efficient strategy for improving its stability and functionality. HBEO-loaded API-NPs is a promising candidate to be used in future foods and supplements for novel applications.