Enhancing the aqueous solubility of curcumin at acidic condition through the complexation with whey protein nanofibrils

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.

Construction of quaternary ammonium chitosan-coated protein nanoparticles as novel delivery system for curcumin: Characterization, stability, antioxidant activity and bio-accessibility

This research aimed to develop a novel, effective, and stable delivery system based on zein (ZE), sodium caseinate (SC), and quaternary ammonium chitosan (HACC) for curcumin (CUR). The pH-driven self-assembly combined with electrostatic deposition methods were employed to construct CUR-loaded ZE-SC nanoparticles with HACC coating (ZE-SC@HACC). The optimized nanocomposite was prepared at ZE:SC:HACC:CUR mass ratios of 1:1:2:0.1, and it had encapsulation efficiency of 89.3%, average diameter of 218.2 nm, and ζ-potential of 40.7 mV. The assembly of composites and encapsulation of CUR were facilitated primarily by hydrophobic, hydrogen-bonding, and electrostatic interactions. Physicochemical stability analysis revealed that HACC coating dramatically enhanced ZE-SC nanoparticles' colloidal stability and CUR's resistance to chemical degradation. Additionally, antioxidant activity and simulated digestion results indicated that CUR-ZE-SC@HACC nanoparticles showed higher free radical scavenging capacity and bio-accessibility of CUR than CUR-ZE-SC nanoparticles and free CUR. Therefore, the ZE-SC@HACC nanocomposite is an effective and viable delivery system for CUR.

Structural characterization and binding interaction of rice glutelin fibrils complexing with curcumin

The rice glutelin (RG), the separated retentate (RGFs) and filtrate (FGFs) fractions from total glutelin fibrils (TGFs) at pH 3.5 were used as carrier for curcumin in this test. The solubility and antioxidant activities of curcumin were improved after binding with protein and fibrils. Compared to other complexes, the RGFs-curcumin complex exhibited a highest curcumin solubility (48.05%) and a superior sustained release property, probably owing to the stable hydrogen bond between the surface groups of fibrils and hydroxyl groups of polyphenols. In addition, thermodynamic parameters revealed that the RG/TGFs/RGFs-curcumin complexes were stabilized by hydrogen bonds and van der Waals forces, whereas FGFs interacted with curcumin through specific electrostatic interaction. Besides, after interacting with curcumin, the fibrils gathered into coarsened and agglutinated fibrillar aggregates, relating to the increment of a-helix and β-sheet structure. These results suggested that RGFs could be a good alternative for curcumin delivery in food industry.

Unveiling the critical pH values triggering the unfolding of soy 7S and 11S globulins and enhancing their encapsulation efficiency

The pH-shifting process is an effective encapsulation method, and it is typically performed at extreme alkaline pH, which severely limits the application. In this study, we found that there were critical pH for the unfolding proteins during pH-shifting from 7 to 12, and upon the critical pH, physiochemical characteristics of protein greatly changed, leading to a sharp increase of encapsulation of hydrophobic actives. Firstly, the critical pH for β-conglycinin (7S) or Glycinin (11S) unfolding was determined by multispectral technology. The critical pH for 7S and 11S were 10.5 and 10.3, respectively. The encapsulation efficiency (EE) obtained by β-conglycinin-curcumin nanocomposite (7S-Cur) (88.80 %) and Glycinin-curcumin nanocomposite (11S-Cur) (88.38 %) at critical pH was significantly higher than that obtained by pH 7 (7S-Cur = 16.66 % and 11S-Cur = 15.78 %), and both values were close to EE obtained by at 12 (7S-Cur = 95.16 % and 11S-Cur = 94.63 %). The large-scale application of hydrophobic functional compounds will be enhanced by the experimental results.

Mussel-inspired protein-based nanoparticles for curcumin encapsulation and promoting antitumor efficiency

Curcumin demonstrated therapeutic potential for cancer. However, its medical application is limited due to low solubility, poor stability and low absorption rate. Here, we used the mussel-inspired functional protein (MPKE) to fabricate the curcumin-carrying nanoparticle (Cur-MPKE) for encapsulating and delivering curcumin. The protein MPKE is composed of the mussel module and zwitterionic peptide. The Dopa group bonding characteristic of the mussel module was leveraged for the self-assembly of nanoparticles, while the superhydrophilic property of the zwitterionic peptide was utilized to enhance the stability of nanoparticles. As expected, MPKE and Cur are tightly bound through hydrogen bonds and dynamic imide bonds to form nanoparticles. Cur-MPKE showed improved solubility and stability in aqueous solutions as well as excellent biocompatibility. Besides, Cur-MPKE also exhibited pH-triggered release and enhanced uptake of curcumin by tumor cells, promoting the antioxidant activity and antitumor effect of curcumin. Moreover, systemic experiments of Cur-MPKE to rats demonstrated that Cur-MPKE significantly inhibited tumor tissue growth and proliferation without causing obvious systemic toxicity. This work provides a new strategy for fabricating the delivery system of curcumin with improved stability, sustainability and bioavailability.

In Situ Nanoencapsulation of Curcumin in Soy Protein Isolate Amyloid-like Aggregates for Enhanced Wound Healing

The importance of amyloid nanofibrils made from food proteins is rising in diverse fields, such as biomedicine and food science. These protein nanofibrils (PNFs) serve as versatile and sustainable building blocks for biomaterials, characterized by their high β-sheet content and an ordered hydrogen bond network. These properties offer both stability and flexibility, along with an extreme aspect ratio and reactive functional groups. Plant-derived amyloid nanofibrils, such as soy protein isolate (SPI) PNFs, are increasingly favored due to their affordability and sustainability compared with animal proteins. This study aimed to explore the formation and application of SPI amyloid-like aggregates (SPIA) and their nanoencapsulation of curcumin (Cur) for biomedical purposes, particularly in wound healing. Under specific conditions of low pH and high temperature, SPIA formed, exhibited an amyloid nature, and successfully encapsulated Cur, thereby enhancing its stability and availability. Spectroscopic and microscopic analyses confirmed structural changes in SPIA upon the incorporation of Cur and the fabrication of SPIA@Cur. The obtained results indicate that in the presence of Cur, SPIA forms faster, attributed to accelerated SPI denaturation, an increased nucleation rate, and enhanced self-assembly facilitated by Cur's hydrophobic interactions and π-π stacking with SPI peptides. In vitro studies demonstrated the biocompatibility, biodegradability, and antioxidant properties of SPIA@Cur along with controlled release behavior. In vivo experiments in male Wistar rats revealed that both SPIA and SPIA@Cur significantly accelerate wound closure compared with untreated wounds, with SPIA@Cur showing slightly better efficacy. The histological analysis supported enhanced wound healing, indicating the potential of SPIA@Cur for biomedical applications.

Preparation and drug release performance of different gelation type polysaccharide/β-lactoglobulin fiber composite gels

Self-assembled protein fibers have attracted much attention in the fields of medicine and food because of their high aspect ratio, polymorphic structure and strong surface hydrophobicity. In this study, three different gelation types of polysaccharides/β-lactoglobulin fiber (Fblg) composite gels, including ionic alginate-Fblg gels, synergistic xanthan-Fblg gels, and double network agar-Fblg gels, were first prepared. The interactions between the polysaccharides and the Fblgs, the microstructure and mechanical properties of the composite gels were investigated using the light scattering, scanning electron microscopy, rheology and texture analysis in order to reveal their formation mechanisms. Then the loading and release properties of the water-soluble drug 5-fluorouracil (5-FU) and the hydrophobic drug curcumin (Cur) through these composite gels were further studied with release mechanisms determined by fitting different release models. It was found that the mechanical properties of the composite gels were determined by the mesh density of the three-dimensional networks formed inside the gels. The network structure and mechanical strength of the alginate-Fblg gels became weaker with the increase of Fblg content at pH 4 due to their attractive interaction which hindered the binding of Ca2+ to ALG, while the network and the strength of the alginate-Fblg gels didn't change much at pH 7 due to the repulsion between Alg and Fblg. The xanthan-Fblg gels formed lamellar structures with enhanced gel network and mechanical strength due to the hydrogen bonding and the electrostatic interaction with Fblg. The Agar-Fblg composite gel formed at 60 °C (above the gelation temperature of agar of 40 °C) had a denser double network structure and higher mechanical strength than that formed at 0 °C due to inhibition of diffusion of Ca2+ as salt bridges for Fblg. The hydrophilic drugs were loaded in the meshes of the composite gels and their release was determined by the structure of the composite gel networks, whereas the hydrophobic drugs were loaded by attaching to the Fblgs in the composite gels and their release was determined by the loading ability and strength of the gels. The study not only provided a new idea for the preparation and application of polysaccharide-protein fiber composite hydrogels, but also provided insights for improving the efficiency of drug carriers.

Molecular Dynamics Insights into the Aggregation Behavior of N-Terminal β-Lactoglobulin Peptides

β-lactoglobulin (BLG) forms amyloid-like aggregates at high temperatures, low pH, and low ionic strengths. At a pH below 2, BLG undergoes hydrolysis into peptides, with N-terminal peptides 1-33 and 1-52 being prone to fibrillization, forming amyloid-like fibrils. Due to their good mechanical properties, BLG amyloids demonstrate great potential for diverse applications, including biosensors, nanocomposites, and catalysts. Consequently, further studies are essential to comprehensively understand the factors governing the formation of BLG amyloid-like morphologies. In this study, all-atom molecular dynamics simulations were employed to explore the aggregation of N-terminal 1-33 and 1-52 BLG peptides under conditions of pH 2 and at 10 mM NaCl concentration. The simulations revealed that the peptides spontaneously assembled into aggregates of varying sizes. The aggregation process was enabled by the low charge of peptides and the presence of hydrophobic residues within them. As the peptides associated into aggregates, there was a concurrent increase in β-sheet structures and the establishment of hydrogen bonds, enhancing the stability of the aggregates. Notably, on average, 1-33 peptides formed larger aggregates compared to their 1-52 counterparts, while the latter exhibited a slightly higher content of β-sheets and higher cluster orderliness. The applied approach facilitated insights into the early stages of amyloid-like aggregation and molecular-level insight into the formation of β-sheets, which serve as nucleation points for further fibril growth.

Fibrous whey protein mediated homogeneous and soft-textured emulsion gels for elderly: Enhancement of bioaccessibility for curcumin

Homogeneous and soft-textured food gels are critical for designing precise and personalized nutrient food for elderly. Effects of whey protein morphology (fibrous and granular) with/without NaCl addition on oil-water state and texture properties of protein emulsion gels were investigated, to explore the feasibility of developing homogeneous and soft-textured food for elderly. Lower gelation temperature and higher stability of its emulsion droplets, resulted in fibrous whey protein emulsion gels (FWPG) had even distribution of embedded oil droplets, compared to native whey protein emulsion gels. FWPG had the lowest hardness and chewiness, and exhibited better tolerance to the harden effects of NaCl on emulsion gels. FWPG can deliver curcumin more effectively during simulated gastrointestinal digestion, as evidenced by higher retention ratio and enhancement of bioaccessibility (increased by ∼ 20 %). This study provided new strategy to fabricate a homogenous emulsion gel using fibrous whey protein and to design multi-nutrient food gels for elderly.

Stability of a novel glycosylated peanut protein isolate delivery system loaded with gallic acid

To overcome the shortcomings of gallic acid (GA) application, a novel glycosylated PPI delivery system was prepared for the first time in this study using the interaction between peanut protein isolate (PPI) and GA. The effects of glycosylation on the structural and functional properties of PPI and the functional properties of nanoparticles were investigated. The optimal nanoparticles were prepared at a mass ratio 1:3 of glycosylated PPI to GA with a particle size of 338.351 ± 18.823 nm and a PDI of 0.222 ± 0.039. Hydrophobic interactions were the main force maintaining the nanoparticle structure. The nanoparticles remained stable when exposed to different environmental factors. In addition, the DPPH and ABTS radical scavenging activities of nanoparticle-embedded GA were 35.94 ± 3.24 % and 62.59 ± 5.07 % after 108 h, which were significantly higher than those of the free GA group (P < 0.05). This study is important for developing GA and hydrophilic polyphenol delivery systems.

Undenatured type II collagen nanofibrils with sodium alginate coating: Structural characterization, physicochemical properties and capability to load curcumin

In this study, the structural design and physicochemical property enhancement of undenatured type II collagen (UC-II) nanofibrils with sodium alginate (SA) coating induced by calcium ions (Ca2+) were investigated. The research aimed to elucidate the impact of Ca2+ concentration on the morphology, thermal stability, and digestive resistance, as well as to assess the potential of UC-II/SA nanofibrils as a delivery system for curcumin (Cur). A series of Ca2+ concentrations (1-9 mM) were methodically applied to optimize the condition that maintains the triple-helical structure of UC-II, thereby enhancing its functional properties. It was found that the Ca2+ level up to 5 mM effectively preserved the structural integrity and improved thermal stability of UC-II, with the added benefit of ensuring the substantial delivery of active fragment to small intestine (70.7 %), which was 3.43 times greater than that of uncoated UC-II. Moreover, incorporating Cur into the UC-II/SA nanofibrils resulted in a 300 times increase in Cur solubility and showcased the superior dispersion stability, antioxidant activity, and sustained release profile during simulated digestion. These findings underscored the dual functionality of the UC-II/SA system as both a stabilizing agent for UC-II nanofibrils and an efficient carrier for Cur delivery.

Application of electro-spraying technique and mathematical modelling for nanoencapsulation of curcumin

Electro-spraying Process (ESP) was used to coat extracted curcumin (CUR) with milk protein isolate (MPI) at equal concentration. The variables were applied voltage (AV), pumps flow rate ratio (PFRR) for coating (CUR with MPI), travelling distance (TD for coating and dehydration), ESE and MPI concentrations. They changed respectively from 7.5 to 27.5 kV, 2-10 times, and 5-25 cm, and 1.5-3.5% (w/w). When the MPI concentration, TD, PFRR, and AV of ESE reached respectively to 2.56 %, 16.64 cm, 6.77 times, and 19.06 kV; the resulting nanoparticle diameter and encapsulation efficiency of CUR coated (with MPI) became 232 nm (minimum) and 80.7% (maximum) values. The scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed that the produced nanoparticles were bead-free, homogeneous, smooth surfaces, and >50% uniformity. While the nanoparticles of CUR had >70% heat resistance (up to 10 min at 120 °C against degradation), it had more than 100% antioxidant capacity in aqueous solution than its free form (because of its appropriate and intact coating). In-vitro studies showed that the nano encapsulated particles released >80% of CUR into the intestinal tract without significant release in simulated gastric fluid.

Encapsulation of rutin in protein nanoparticles by pH-driven method: impact of rutin solubility and mechanisms

BACKGROUND

The use of rutin in the food industry is limited by its poor solubility. Encapsulation can be used as an effective way to improve polyphenol solubility. Proteins with high safety, biocompatibility and multiple binding sites are known as the most promising encapsulating carriers. Therefore, the improvement of rutin solubility by pH-driven encapsulation of rutin in soy protein isolate (SPI) nanoparticles, as well as the form of rutin after encapsulation and rutin-protein binding index were investigated.

RESULTS

SPI had a high encapsulation efficiency (87.5%) and loading amount (10.6%) for rutin. When the mass ratio of protein to rutin was 5:1, the highest concentration of rutin in solution was 3.27 g L-1 , which was a 51.57-fold increase compared to the original rutin. At this situation, rutin transformed from crystalline to amorphous form. During the formation of nanoparticles, SPI was in a dynamic change of unfolding and refolding. Rutin deprotonated in alkaline conditions increasing its solubility and bound to protein to form nanoparticles during the process of returning to neutral. Hydrophobic interactions and hydrogen bonding promoted the formation of the nanoparticles and there were at least 1-2 binding sites between rutin and each SPI molecule.

CONCLUSION

The results suggested that encapsulation of rutin in protein nanoparticles can effectively increase the solubility of rutin. This study may provide important information for the effective utilization of polyphenol functional foods. © 2023 Society of Chemical Industry.

Effect of gum arabic and thermal modification of whey protein isolate on the characteristics of Cornus officinalis flavonoid microcapsules

Whey protein isolates (WPIs) were treated at 50, 60, 70, and 80°C to obtain thermally modified WPI. Gum arabic (GA) and thermal modification of WPI were used as novel wall materials to improve the quality of Cornus officinalis flavonoid (COF) microcapsules using microwave freeze-drying technique in this study. Results showed that all the thermal modification treatment decreased emulsifying activity index of WPI, whereas the solubility and emulsifying stability index (ESI) of WPI gradually increased with the increase of heating temperature. Compared to the untreated protein, the thermal modification treatment at 70°C increased the solubility and ESI of WPI by 14.91% ± 0.71% and 26.70% ± 0.94%, respectively. The microcapsules prepared with the modified protein at 60°C had the highest encapsulation efficiency (95.13% ± 2.36%), the lowest moisture content (1.42% ± 0.34%), and the highest solubility (84.41% ± 0.91). Scanning electron microscopy images showed that COF microcapsules were uniformly spherical, and the sizes of the microcapsules were in the following order: 12.42 ± 0.37 µm (80°C) > 11.7 ± 0.23 µm (untreated group) > 9.44 ± 0.33 µm (60°C) > 9.24 ± 0.14 µm (50°C) > 7.69 ± 0.29 µm (70°C). In the simulated in vitro digestion experiments, the release rate of COF microcapsules in the gastric digestion phase was less than that in the intestinal digestion phase, and it reached 66.46% at intestinal digestion phase. These results suggested that heated WPI and GA could be an effective nanocarrier to enhance the stability of COF.

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

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

A double-layer cellulose/pectin-soy protein isolate-pomegranate peel extract micro/nanofiber dressing for acceleration of wound healing

Multi-layered wound dressings can closely mimic the hierarchical structure of the skin. Herein, a double-layer dressing material is fabricated through electrospinning, comprised of a nanofibrous structure as a healing-support layer or the bottom layer (BL) containing pectin (Pec), soy protein isolate (SPI), pomegranate peel extract (P), and a cellulose (Cel) microfiber layer as a protective/monitoring layer or top layer (TL). The formation of a fine bilayer structure was confirmed using scanning electron microscopy. Cel/Pec-SPI-P dressing showed a 60.05 % weight loss during 7 days of immersion in phosphate buffered solution. The ultimate tensile strength, elastic modulus, and elongation at break for different dressings were within the range of 3.14-3.57 MPa, 32.26-36.58 MPa, and 59.04-63.19 %, respectively. The release of SPI and phenolic compounds from dressings were measured and their antibacterial activity was evaluated. The fabricated dressing was non-cytotoxic following exposure to human keratinocyte cells. The Cel/Pec-SPI-P dressing exhibited excellent cell adhesion and migration as well as angiogenesis. More importantly, in vivo experiments on Cel/Pec-SPI-P dressings showed faster epidermal layer formation, blood vessel generation, collagen deposition, and a faster wound healing rate. Overall, it is anticipated that the Cel/Pec-SPI-P bilayer dressing facilitates wound treatment and can be a promising approach for clinical use.

Wheat gluten amyloid fibrils: Conditions, mechanism, characterization, application, and future perspectives

Amyloid fibrils have excellent structural characteristics, such as a high aspect ratio, excellent stiffness, and a wide availability of functional groups on the surface. More studies are now focusing on the formation of amyloid fibrils using food proteins. Protein fibrillation is now becoming recognized as a promising strategy for enhancing the function of food proteins and expanding their range of applications. Wheat gluten is rich in glutamine (Q), hydrophobic amino acids, and the α-helix structure with high β-sheet tendency. These characteristics make it very easy for wheat gluten to form amyloid fibrils. The conditions, formation mechanism, characterization methods, and application of amyloid fibrils formed by wheat gluten are summarized in this review. Further exploration of amyloid fibrils formed by wheat gluten will reveal how they can play a significant role in food, biology, and other fields, especially in medicine.

Determination of the critical pH for unfolding water-soluble cod protein and its effect on encapsulation capacities

Hydrophobic polyphenols, with a variety of physiological activities, are often practically limited due to their low water solubility and chemical instability, among which curcumin (Cur) is a representative hydrophobic polyphenol. To improve Cur, the cod protein (CP)-Cur composite particles (CP-Cur) were successfully prepared using the pH-shift method, but this pH-shift method (7-12-7) required a higher pH, which limited application and increased cost. The critical pH of CP structure unfolding during pH-shift and its encapsulation effect on Cur were investigated in this paper. During the pH-shift process, the critical pH of the structural unfolding of CP was pH 10, and the degree of protein structure unfolding was higher, which was attributed to the increasing electrostatic repulsion, and the weakened hydrogen bond and hydrophobic interaction. The encapsulation efficiency of CP-Cur formed after pH 10-shift was higher than that formed after pH 9.8-shift, which increased by 22.17 %. At pH 9.8, the binding sites in CP reached saturation at the molar ratio of 10, while at pH 10 and 10.2, the binding sites in CP both reached saturation at the molar ratio of 14, also indicating that the protein treated with critical pH could bind more Cur. The binding between Cur and CP was mostly hydrophobic interaction, accompanied by hydrogen bonding and electrostatic interactions. The above results verified the necessity of critical pH in the experiment, indicating that critical pH could indeed improve the encapsulation effect and obtain a higher encapsulation efficiency. This work will help improve the large-scale application of hydrophobic functional substances in production.

Construction of curcumin-fortified juices using their self-derived extracellular vesicles as natural delivery systems: grape, tomato, and orange juices

Different fruit and vegetable juices were first used to encapsulate curcumin to improve its solubility, stability, and bioaccessibility, which is expected to enable designing of polyphenol-enriched beverages and impact human health and well-being. Briefly, fruit and vegetable-derived extracellular vesicles usually serve as transport and communication tools between different cells, which means they also may be utilized as delivery carriers for other bioactive agents. Curcumin, as a model polyphenol with many physiological activities, typically has low water-solubility, stability, and bioaccessibility. Therefore, extracellular vesicles were applied to load curcumin to overcome these challenges and to facilitate its incorporation into fruit and vegetable juices. Three kinds of curcumin-loaded fruit and vegetable juices, including curcumin-loaded grape (Cur-G), tomato (Cur-T), and orange (Cur-O) juices, exhibited higher encapsulation efficiency (>80%) than others. The patterns of XRD and FTIR confirmed that curcumin moved into extracellular vesicles in the amorphous form and that the hydrogen bonding force was found between them. Three kinds of fruit and vegetable juices can significantly enhance the solubility, stability and bioavailability of curcumin, but the degrees of improvement are different. For instance, Cur-O exhibited the highest encapsulation efficiency, chemical stability, and effective bioaccessibility than Cur-G and Cur-T. In summary, this study shows that natural fruit and vegetable juices can effectively improve the solubility, stability and bioaccessibility of active polyphenols, which is expected to enable successful designing of nutrient-enriched beverages with a simple method according to various needs of people and be directly applied to food processing and home production.

Valorization of pistachio industrial waste: Simultaneous recovery of pectin and phenolics, and their application in low-phenylalanine cookies for phenylketonuria

This study introduces a sustainable approach to simultaneously produce pectin and phenolic compounds from pistachio industrial waste and applies them in the formulation of low-phenylalanine cookies. The co-optimization process was performed using the microwave-assisted technique and a Box-Behnken design, considering four variables and two responses: pectin yield and total phenolic content (TPC). The co-optimized condition (microwave power of 700 W, irradiation time of 210 s, pH level of 1.02, and LSR of 20 mL/g) resulted in a pectin yield of 15.85 % and a TPC of 10.12 %. The pectin obtained under co-optimized condition was evaluated for its physicochemical, structural, and thermal properties and the phenolic extract for its antiradical activity. Characterization of the pectin sample revealed a high degree of esterification (44.21 %) and a galacturonic acid-rich composition (69.55 %). The average molecular weight of the pectin was determined to be 640.236 kDa. FTIR and 1H NMR spectroscopies confirmed the structure of pectin, with an amorphous nature and high thermal stability observed through XRD and DSC analysis. Additionally, the extract exhibited significant antiradical activity comparable to butylated hydroxyanisole and ascorbic acid. The isolated ingredients were used to formulate low-protein, low-phenylalanine cookies for phenylketonuria patients. The addition of 0.5 % pectin and 1 mL/g extract led to increased moisture content (from 9.05 to 12.89 %) and specific volume (from 7.28 to 9.90 mL/g), decreased hardness (from 19.44 to 10.39 N × 102), and improved antioxidant properties (from 5.15 % to 44.60 % inhibition) of the cookies. Importantly, there was no significant increase observed in the phenylalanine content of the samples with pectin and extract addition. Furthermore, sensory evaluation scores demonstrated significantly higher scores for taste, odor, texture, and overall acceptability in cookies enriched with 0.5 % pectin and 1 mL/g extract, with scores of 4.53, 3.93, 4.40, and 4.60, respectively.

Nano techniques: an updated review focused on anthocyanin stability

Anthocyanins (ACNs) are one of the subgroups of flavonoids and getting intensive attraction due to the nutritional values. However, their application of ACNs is limited due to their poor stability and bioavailability. Accordingly, nanoencapsulation has been developed to enhance its stability and bio-efficacy. This review focuses on the nano-technique applications of delivery systems that be used for ACNs stabilization, with an emphasis on physicochemical stability and health benefits. ACNs incorporated with delivery systems in forms of nano-particles and fibrils can achieve advanced functions, such as improved stability, enhanced bioavailability, and controlled release. Also, the toxicological evaluation of nano delivery systems is summarized. Additionally, this review summarizes the challenges and suggests the further perspectives for the further application of ACNs delivery systems in food and medical fields.

Recent developments in natural biopolymer based drug delivery systems

Targeted delivery of drug molecules to diseased sites is a great challenge in pharmaceutical and biomedical sciences. Fabrication of drug delivery systems (DDS) to target and/or diagnose sick cells is an effective means to achieve good therapeutic results along with a minimal toxicological impact on healthy cells. Biopolymers are becoming an important class of materials owing to their biodegradability, good compatibility, non-toxicity, non-immunogenicity, and long blood circulation time and high drug loading ratio for both macros as well as micro-sized drug molecules. This review summarizes the recent trends in biopolymer-based DDS, forecasting their broad future clinical applications. Cellulose chitosan, starch, silk fibroins, collagen, albumin, gelatin, alginate, agar, proteins and peptides have shown potential applications in DDS. A range of synthetic techniques have been reported to design the DDS and are discussed in the current study which is being successfully employed in ocular, dental, transdermal and intranasal delivery systems. Different formulations of DDS are also overviewed in this review article along with synthesis techniques employed for designing the DDS. The possibility of these biopolymer applications points to a new route for creating unique DDS with enhanced therapeutic qualities for scaling up creative formulations up to the clinical level.

Laccase-Induced Gelation of Sugar Beet Pectin-Curcumin Nanocomplexes Enhanced by Genipin Crosslinking

Research on the use of polysaccharides as hydrophobic bioactive carriers instead of proteins is still scarce. Sugar beet pectin (SBP) contains a small amount of protein and is a potential carrier for loading curcumin. In this work, SBP encapsulation, genipin crosslinking, and laccase-induced gelation were used to develop novel jelly food and improve the stability of curcumin without the incorporation of oil. By mixing the SBP solution (40 mg/mL) with curcumin powder (25 mg/mL SBP solution), an SBP-curcumin complex (SBP-Cur) was fabricated with a loading amount of 32 mg/g SBP, and the solubility of curcumin improved 116,000-fold. Fluorescence spectroscopy revealed that hydrophobic interactions drove the complexation of curcumin and SBP. Crosslinked by genipin (10 mM), SBP-Cur showed a dark blue color, and the gel strength of laccase-catalyzed gels was enhanced. Heating and UV radiation tests suggested that the genipin crosslinking and gelation strategies substantially improved the stability of curcumin. Because of the unique UV-blocking capacity of blue pigment, crosslinked samples retained 20% more curcumin than control samples. With the enhanced stability of curcumin, the crosslinked SBP-curcumin complexes could be a functional food ingredient used in functional drinks, baked food, and jelly food.

Formation, stability and in vitro digestion of curcumin loaded whey protein/ hyaluronic acid nanoparticles: Ethanol desolvation vs. pH-shifting method

Curcumin (CUR) was encapsulated in whey protein isolate/hyaluronic acid (WPI/HA) electrostatic nanoparticles at pH 5.4, 4.4, 3.4 and 2.4 using ethanol desolvation (DNP) or pH-shifting (PSNP) method. The prepared nanoparticles were characterized and compared for physiochemical properties, structure, stability, and in vitro digestion. PSNPs had smaller particle size, more uniform distribution, and higher encapsulation efficiency than DNPs. Main driving forces involved for fabricating the nanoparticles were electrostatic forces, hydrophobic forces, and hydrogen bonds. PSNP exhibited better resistance towards salt, thermal treatment, and long-term storage while DNPs showed stronger protection for CUR against thermal degradation and photodegradation. Stability of nanoparticles increased with decreasing pH values. In vitro simulated digestion exhibited that DNPs had lower release rate of CUR in SGF and higher antioxidant activity of its digestion products. Data may provide a comprehensive reference for selection of loading approach when constructing nanoparticles based on proteins/polysaccharides electrostatic complexes.

Hofmeister anion effects synergize with microbial transglutaminase to enhance the techno-functional properties of pea protein

Pea protein are emerging as the most potential alternative for meat products, but its application was hindered by their weaker gelling properties. Here, the feasibility of combining the Hofmeister anion (CO₃^2-, Citrate^3-, and SO₄^2-) effect with microbial transglutaminase (MTG) cross-linking strategy to improve the techno-functional properties of pea protein was studied. Hofmeister anions or/and MTG treatment of pea protein caused a clear shift in far-UV CD spectra towards β-turn and random coil structures. Furthermore, Hofmeister anion and MTG-induced crosslinking caused a reduction of surface hydrophobicity in contrast with anions-treated. Compared to CO₃^2- and SO₄^2-, Citrate^3- treatment can better improve the efficiency of MTG-crosslinking, as demonstrated by a reduction in free amino group contents and an increase in mean diameter size. Using MTG in combination with Hofmeister anions showed significantly improved foam property and gel hardness as well as decrease gelation temperature of pea protein, specifically Citrate^3- treatment. Thus, this research provides a novel and effective method to improve the effect of MTG-cross-linked pea protein, which will play an essential role in future food production.

Effects of curcumin, phycocyanin, or modified lycopene colorants on the physicochemical and sensory properties of whey protein-cellulose nanocrystal packaging films

To utilize natural hydrophobic/hydrophilic colorants to manufacture good quality and attractive packaging films, we investigated the effects of natural colorants (curcumin, phycocyanin, modified lycopene, and their mixed colorants) on the physicochemical and sensory properties of whey protein isolate-cellulose nanocrystal packaging film. Owing to the improvement in hydrophobicity and spatial density, moisture content (MC) and water vapor permeability (WVP) of films containing curcumin were reduced by 16.91% and 8.49%, respectively, in contrast to that, MC and WVP increased by 10.75% and 4.09%, respectively, in film containing modified lycopene. Mechanical testing, infrared spectra, and X-ray diffraction revealed the retention of structural properties of protein matrix. Rate-All-That-Apply evaluation indicated that films containing colorants enriched tactile and visual sensory characteristics. The eye tracking testing of packed foods showed that preferential attraction depends on the color of the food itself. Thus, a consumer-oriented multi-colored packaging film with good performance was achieved.

Development, Characterization and Resveratrol Delivery of Hollow Gliadin Nanoparticles: Advantages over Solid Gliadin Nanoparticles

Hollow nanoparticles have attracted extensive attention due to their advantages such as high loading capacity and superior stability. However, the complexity of the preparation process and harmfulness of the used raw materials have limited their application in the food field. Based on this, hollow gliadin nanoparticles (HGNPs) were developed using a Na₂CO₃ sacrificial template method. The findings of this study suggested that HGNPs could be regarded as a delivery system for resveratrol (Res) and they exhibited excellent delivery performance. Compared with solid gliadin nanoparticles (SGNPs), the HGNPs displayed smaller particle sizes, better physical stability, higher encapsulation efficiency, stronger resistance to ultraviolet light and a more sustained release of Res in the gastrointestinal tract. This work is of practical significance for the development and utilization of protein-based nanoparticles with hollow structures as a delivery system for sensitive bioactives.

Efficient encapsulation of fat-soluble food-derived biofunctional substances (curcumin as an example) in dual-modified starch-based nanoparticles containing large conjugated systems

Acid-ethanol hydrolysis and subsequent cinnamic acid (CA) esterification were employed to prepare a series of dual-modified starches efficiently loaded with curcumin (Cur) utilizing large conjugation systems provided by CA. Structures of the dual-modified starches were confirmed by IR and NMR, and their physicochemical properties were characterized by SEM, XRD and TGA. The nanoparticles fabricated from the dual-modified starch have perfect spherical shape (250.7-448.5 nm, polydispersity index <0.3), excellent biosafety (no hematotoxicity, no cytotoxicity, no mutagenicity) and high loading of Cur (up to 26.7 % loading). By XPS analysis, this high loading is believed to be supported by the synergistic effect of hydrogen bonding (provided by hydroxyl groups) and π-π interactions (provided by large conjugation system). In addition, the encapsulation of dual-modified starch nanoparticles effectively enhanced the water solubility (18-fold) and physical stability (6-8-fold) of free Cur. In vitro gastrointestinal release showed that Cur-encapsulated dual-modified starch nanoparticles were released more preferably than free Cur and that the Korsmeyer-Peppas model was the most suitable release model. These studies suggest that dual-modified starches containing large conjugation systems would be a better alternative for encapsulating fat-soluble food-derived biofunctional substances in functional food and pharmaceutical applications.

Fabrication and characterization of self-assembled whey protein isolate/short linear glucan core-shell nanoparticles for sustained release of curcumin

The aim of this research was to prepare a bistratal nanocomplex with a high loading capacity (LC) and harsh environment stability for controlled release of curcumin (Cur) in gastrointestinal conditions. Whey protein isolate (WPI)/short linear glucan (SLG) core-shell nanoparticles were fabricated by self-assembly for the delivery of Cur. The results showed that Cur@WPI@SLG nanoparticles had a relatively high LC (12.89 %) and small particle size (89.4 nm). The nanocomplex remained relatively stable in extreme pH conditions (2-4 and 8-10), high temperatures (60-70 °C), and ionic strength (<400 mM). Core-shell nanostructures facilitated the sustained release of Cur in simulated gastrointestinal conditions. In addition, the nanocomplex had little cytotoxicity at high concentrations, yet significantly enhanced the DPPH scavenging activity and reducing power of Cur. This delivery system will significantly improve the sustained release effect of Cur and broaden the application of hydrophobic nutrients in foods.

Fibrillation modification to improve the viscosity, emulsifying, and foaming properties of rice protein

Fibrillation of food proteins has attracted considerable attention as it can improve and broaden the functionality of proteins. In this study, we prepared three kinds of rice protein (RP) fibrils with different structural characteristics by the regulation of NaCl and explored the effect of protein structure on viscosity, emulsifying, and foaming properties. AFM results showed fibrils formed at 0 and 100 mM NaCl were mainly in the range of 50-150 nm and 150-250 nm, respectively. Fibrils formed at 200 mM NaCl were in the range of 50-500 nm and protein fibrils longer than 500 nm increased. There was no significant difference between their height and periodicity. Fibrils formed at 0 and 100 mM NaCl were more flexible and unordered than those formed at 200 mM NaCl. The viscosity consistency index K of native RP and fibrils formed at 0, 100, and 200 mM NaCl were determined. The K value of fibrils was higher than that of native RP. The emulsifying activity index, foam capacity and foam stability were enhanced by fibrillation, while longer fibrils exhibited lower emulsifying stability index, which may be because long fibrils resulted in difficulty of cover of emulsion droplets. In summary, our work provided a valuable reference for improving the functionality of rice protein and facilitated the development of protein-based foaming agents, thickeners, and emulsifiers.

Fabrication of glycated yeast cell protein via Maillard reaction for delivery of curcumin: improved environmental stability, antioxidant activity, and bioaccessibility

BACKGROUND

The application of curcumin (CUR) in the food industry is limited by its instability, hydrophobicity and low bioavailability. Yeast cell protein (YCP) is a by-product of spent brewer's yeast, which has the potential to deliver bioactive substances. However, the environmental stresses such as pH, salt and heat treatment has restricted its application in the food industry. Maillard reaction as a non-enzymatic browning reaction can improve protein stability under environmental stress.

RESULTS

The CUR was successfully encapsulated into the hydrophobic core of YCP/glycated YCP (GYCP) and enhanced by hydrogen bonding, resulting in static fluorescence quenching of YCP/GYCP. The average diameter and dispersibility of GYPC-CUR nanocomplex were significantly improved after glucose glycation (121.40 nm versus 139.70 nm). Moreover, the encapsulation capacity of CUR was not influenced by glucose glycation. The oxidative stability and bioaccessibility of CUR in nanocomplexes were increased compared with free CUR, especially complexed with GYCP conjugates.

CONCLUSION

Steric hindrance provided by glucose conjugation improved the enviriomental stability, oxidative activity and bioaccessibility of CUR in nanocomplexes. Thus, glucose-glycated YCP has potential application as a delivery carrier for hydrophobic compounds in functional foods. © 2022 Society of Chemical Industry.

Co-encapsulation of resveratrol in fish oil microcapsules optimally stabilized by enzyme-crosslinked whey protein with gum Arabic

O/W emulsion and its spray-dried microcapsule contain the oil phase and the protein matrix, providing the potential to co-encapsulate different antioxidants. However, antioxidants were generally encapsulated in the oil phase of microcapsule, its protein matrix is rarely used. It is first to prove the possibility to encapsulate resveratrol in the emulsified oil droplets at high wall/core ratios. The optimal microcapsule with 1.75% surface oil was fabricated with 15% transglutaminase-crosslinked WPI (TGase-WPI) and 5% gum Arabic (GA). Resveratrol mainly located in the protein matrix of initial emulsion and reconstituted microcapsule. The effects of TGase-WPI/GA microcapsule and resveratrol co-encapsulation on DHA/EPA and lipid hydroperoxides/TBARS were different. The interfacial protein, the partition of resveratrol in the emulsified oil droplets and its storage stability and inhibitory effect on size change of reconstituted microcapsules increased as the polyphenol increased. These results expand the potential use of spray-dried microcapsules as co-encapsulation carriers.

Effect of Different Seed Crystals on the Supersaturation State of Ritonavir Tablets Prepared by Hot-Melt Extrusion

Hot-melt extrusion (HME) is a technology increasingly common for the commercial production of pharmaceutical amorphous solid dispersions (ASDs), especially for poorly water-soluble active pharmaceutical ingredients (APIs). However, recrystallization of the APIs during dissolution must be prevented to maintain the supersaturation state enabled by ASD. Unfortunately, the amorphous formulation may be contaminated by seed crystals during the HME manufacturing process, which could lead to undesirable crystal growth during the dissolution process. In this study, the dissolution behavior of ritonavir ASD tablets prepared using both Form I and Form II polymorphs was examined, and the effects of different seed crystals on crystal growth rates were investigated. The aim was to understand how the presence of seed crystals can impact the dissolution of ritonavir, and to determine the optimal polymorph and seeding conditions for the production of ASDs. The results showed that both Form I and Form II ritonavir tablets had similar dissolution profiles, which were also similar to the reference listed drug (RLD). However, it was observed that the presence of seed crystals, particularly the metastable Form I seed, led to more precipitation compared to the stable Form II seed in all formulations. The Form I crystals that precipitated from the supersaturated solution were easily dispersed in the solution and could serve as seeds to facilitate crystal growth. On the other hand, Form II crystals tended to grow more slowly and presented as aggregates. The addition of both Form I and Form II seeds could affect their precipitation behaviors, and the amount and form of the seeds had significant effects on the precipitation process of the RLD tablets, as are the tablets prepared with different polymorphs. In conclusion, the study highlights the importance of minimizing the contamination risk of seed crystals during the manufacturing process and selecting the appropriate polymorph for the production of ASDs.

Reducing disulfide bonds as a robust strategy to facilitate the self-assembly of cod protein fabricating potential active ingredients-nanocarrier

In this study, a novel method was developed to encapsulate hydrophobic compounds by self-assembly of cod protein (CP) triggered by breaking disulfide bonds. Curcumin (Cur), a representative lipid-soluble polyphenol, was selected as a model to evaluate the potential of CP nanoparticles as novel and accessible nanocarriers. Results showed that the protein structure gradually unfolded with increasing dithiothreitol (DTT) concentration, indicating that S-S cleavage was conducive to forming a looser structure. The resultant unfolded CP exposed more hydrophobic sites, facilitating its interaction with hydrophobic compounds. The encapsulation efficiency (EE) of formed CP-Cur nanoparticles was relatively high, reaching 99.09%, 98.8%, and 89.77% when the mass ratios of CP to Cur were 20:1, 10:1, and 5:1 (w/v), respectively. The hydrophobic interaction, weak van der Waals, and hydrogen bond were the forces contributing to the formation of CP-Cur nanoparticles, whereas the hydrophobic interaction played a crucial role. The CP-Cur complex exhibited increased stability and a homogeneous-stable structural phase. Thus, this research not only proposed a novel and simple encapsulation method of hydrophobic bioactive compounds but also provided a theoretical reference for the application of reductants in food or pharmacy system.

Curcumin-infused xerogel-based nutraceutical development and its 4D shape-shifting behavior

Cereal-based functional foods with shape-changing (four-dimensional [4D]) properties is a novel approach in the current scenario. The main objective of the research is to develop a bioactive compound incorporated in flat two-dimensional xerogel and its hydromorphic three-dimensional shape transformation. The spray-dried curcumin at three different concentrations was incorporated with hydrogel (wheat-barley flour 8%), and flat xerogel was formed by sessile drop drying at 30°C and 78% relative humidity. The top smooth and rough bottom surface of xerogel provided anisotropic swelling properties during the shape transformation. The antimicrobial and antioxidant properties of xerogel were examined, and the retention of curcumin during the shape transformation was also examined during the research. The porous structure of barley-wheat xerogel has enhanced the incorporation of water-insoluble bioactive components like curcumin. The diffusion properties of curcumin xerogel provided an antimicrobial effect against gram-negative pathogenic bacteria. The optimum temperature (70°C) during the shape-shifting provides the retention of bioavailability and functional properties of curcumin. The work describes the opportunities for developing xerogel incorporated with more bioactive and functional components and study its stability and hydromorphic 4D shape-changing behavior. PRACTICAL APPLICATION: Xerogel is a good carrier for different bioactive components. The development of curcumin-infused biodegrade, non-toxic, and cereal-based xerogel provide an excellent opportunity for the delivery of curcumin in a cost-effective way. The shape-changing easily consumable forms of xerogel will attract more consumers, and it retains the bioavailability of infused compounds during processing.

Validation of Layer-By-Layer Coating as a Procedure to Enhance Lactobacillus plantarum Survival during In Vitro Digestion, Storage, and Fermentation

Probiotics are sensitive to phenolic antibacterial components and the extremely acidic environment of blueberry juices. Layer-by-layer (LbL) coating using whey protein isolate fibrils (WPIFs) and sodium alginate (ALG), carboxymethyl cellulose (CMC), or xanthan gum (XG) was developed to improve the survival rate of Lactobacillus plantarum 90 (LP90) in simulated digestion, storage, and fermented blueberry juices. The LbL-coated LP90 remained at 6.65 log CFU/mL after 48 h of fermentation. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) indicated that dense and rough wall networks were formed on the surface of LP90, maintaining the integrity of LP90 cells after the coating. Stability evaluation showed that the LbL-coated LP90 had a much higher survival rate in the processes of simulated gastrointestinal digestion and storage. The formation mechanism of the LbL coating process was further explored, which indicated that electrostatic interactions and hydrogen bonding were involved. The LbL coating approach has great potential to protect and deliver probiotics in food systems.

Research progress on albumin-based hydrogels: Properties, preparation methods, types and its application for antitumor-drug delivery and tissue engineering

Albumin is derived from blood plasma and is the most abundant protein in blood plasma, which has good mechanical properties, biocompatibility and degradability, so albumin is an ideal biomaterial for biomedical applications, and drug-carriers based on albumin can better reduce the cytotoxicity of drug. Currently, there are numerous reviews summarizing the research progress on drug-loaded albumin molecules or nanoparticles. In comparison, the study of albumin-based hydrogels is a relatively small area of research, and few articles have systematically summarized the research progress of albumin-based hydrogels, especially for drug delivery and tissue engineering. Thus, this review summarizes the functional features and preparation methods of albumin-based hydrogels, different types of albumin-based hydrogels and their applications in antitumor drugs, tissue regeneration engineering, etc. Also, potential directions for future research on albumin-based hydrogels are discussed.

Incorporation of silver nanoparticles/curcumin/clay minerals into chitosan film for enhancing mechanical properties, antioxidant and antibacterial activity

It is popular that natural organics are served as green reducing and end-capping reagent for synthesis of functional nanoparticles. In this study, curcumin, a natural pigment, was employed to prepare silver nanoparticles (AgNPs) as a coloring, reducing and end-capping agent by an eco-friendly, economic and facile approach in the presence of different clay minerals, including palygorskite, montmorillonite and mixed-dimensional palygorskite clay. It was found that the phenolic hydroxyl groups or carbonyl groups of curcumin played a crucial role to reduce silver ions into AgNPs with the ginger color. Meanwhile, incorporation of clay minerals could induce the in-situ heterogeneous nucleation of AgNPs on the surface or/and interlayer of the involved clay minerals. It effectively prevented from the aggregations and resulted in uniform dispersion of AgNPs with a diameter of 30-40 nm. Furthermore, the as-prepared nanocomposites exhibited a higher antioxidant (>90%) and antibacterial activity. Due to the synergistic effect of each component among the nanocompositions, the nanocomposites derived from different clay minerals were employed as multifunctional nanofillers to design functional chitosan composite films. By contrast, the chitosan composite films containing curcumin-capped AgNPs/mixed-dimensional palygorskite clay nanocomposites exhibited the best mechanical properties, antioxidant and antibacterial activities. Compared with the chitosan films, the tensile strength and elongation at break of composite films increased by 15.90 MPa and 27.27%, respectively. The inactivation rate of the composite films against Escherichia coli and Staphylococcus aureus had reached 100%. Therefore, the obtained composite film with the ginger color exhibited excellent mechanical, water resistance, antioxidant and antibacterial properties, and it was expected to develop a great potential functional packaging materials.

Nanofibrils of food-grade proteins: Formation mechanism, delivery systems, and application evaluation

Due to the high aspect ratio, appealing mechanical characteristics, and various adjustable functional groups on the surface proteins, food-grade protein nanofibrils have attracted great research interest in the field of food science. Fibrillation, known as a process of peptide self-assembly, is recognized as a common attribute for food-grade proteins. Converting food-grade proteins into nanofibrils is a promising strategy to broaden their functionality and applications, such as improvement of the properties of gelling and emulsifying, especially for constructing various delivery systems for bioactive compounds. Protein source and processing conditions have a great impact on the size, structure, and morphology of nanofibrils, resulting in extreme differences in functionality. With this feature, it is possible to engineer nanofibrils into four different delivery systems, including gels, microcapsules, emulsions, and complexes. Construction of nanofibril-based gels via multiple cross-linking methods can endow gels with special network structures to efficiently capture bioactive compounds and extra mechanical behavior. The adsorption behavior of nanofibrils at the interface is highly complex due to the influence of several intrinsic factors, which makes it challenging to form stabilized nanofibril-based emulsion systems. Based on electrostatic interactions, microcapsules and complexes prepared using nanofibrils and polysaccharides have combined functional properties, resulting in adjustable release behavior and higher encapsulation efficiency. The bioactive compounds delivery system based on nanofibrils is a potential solution to enhance their absorption in the gastrointestinal tract, improve their bioavailability, and deliver them to target organs. Although food-grade protein nanofibrils show unknown toxicity to humans, further research can contribute to broadening the application of nanofibrils in delivery systems.

Strategies for Improving Bioavailability, Bioactivity, and Physical-Chemical Behavior of Curcumin

Curcumin (CCM) is one of the most frequently explored plant compounds with various biological actions such as antibacterial, antiviral, antifungal, antineoplastic, and antioxidant/anti-inflammatory properties. The laboratory data and clinical trials have demonstrated that the bioavailability and bioactivity of curcumin are influenced by the feature of the curcumin molecular complex types. Curcumin has a high capacity to form molecular complexes with proteins (such as whey proteins, bovine serum albumin, β-lactoglobulin), carbohydrates, lipids, and natural compounds (e.g., resveratrol, piperine, quercetin). These complexes increase the bioactivity and bioavailability of curcumin. The current review provides these derivatization strategies for curcumin in terms of biological and physico-chemical aspects with a strong focus on different type of proteins, characterization methods, and thermodynamic features of protein–curcumin complexes, and with the aim of evaluating the best performances. The current literature review offers, taking into consideration various biological effects of the CCM, a whole approach for CCM-biomolecules interactions such as CCM-proteins, CCM-nanomaterials, and CCM-natural compounds regarding molecular strategies to improve the bioactivity as well as the bioavailability of curcumin in biological systems.

Curcumin-loaded complex coacervate made of mung bean protein isolate and succinylated chitosan as a novel medium for curcumin encapsulation

A novel complex coacervate based on mung bean protein (MBP) and succinylated chitosan (SC) was developed in order to encapsulate curcumin to enhance its antioxidant and release properties. The optimum pH and MBP/SC ratio for fabrication of the complex coacervate were determined as 5.5 and 3:1, respectively. The MBP/SC complexes exhibited high affinity toward curcumin with encapsulation efficiency of 89.65%. The curcumin-loaded MBP with succinyl chitosan (c-MBP/SC) exhibited antioxidant properties investigated by DPPH and reducing power assays. c-MBP/SC also showed significant photo stability and acceptable controlled release behavior in simulated gastrointestinal conditions. Fluorescence results indicated that curcumin interacted with the hydrophobic areas available in c-MBP/SC. FTIR results showed the successful encapsulation of curcumin in the hydrophobic core of the complex, followed by minor changes in MBP conformation. Analysis of zeta potential revealed that MBP/SC particles were synthesized successfully at the pH value of 5.5 due to conformational changes of MBP. The conformational changes in protein structure were confirmed by Nile Red fluorescence anisotropy. As a result, c-MBP/SC could be considered as a promising carrier for curcumin encapsulation in food formulations with enhanced dispersity characteristic.