Development of pH-driven zein/tea saponin composite nanoparticles for encapsulation and oral delivery of curcumin

Tea saponin-Zein binary complex as a quercetin delivery vehicle: preparation, characterization, and functional evaluation

In this study, in order to solve the application problems of poor water solubility and low bioavailability of quercetin, we prepared a nano-delivery system with core-shell structure by anti-solvent method, including a hydrophilic shell composed of tea saponin and a hydrophobic core composed of Zein, which was used to improve the delivery efficiency and biological activity of quercetin. Through the optimal experiments, the loading rate and encapsulation rate of nanoparticles reached 89.41 % and 7.94 % respectively. And the water solubility of quercetin is improved by 30.16 times. At the same time, the quercetin acted with Zein through non-covalent interaction and destroyed its spatial network through structural characterization, while tea saponin covered the surface of Zein through electrostatic interaction, making it change into amorphous state. In addition, the addition of tea saponin makes the nanoparticles remain stable under the changes of external environment. During simulating gastrointestinal digestion procedure, ZQTNPs has higher release rate and bioavailability than free quercetin. Importantly, ZQTNPs can overcome the limitations of a single substance through synergy. These results will promote the innovative development of quercetin precision nutrition delivery system.

Encapsulation of polyphenols in protein-based nanoparticles: Preparation, properties, and applications

Polyphenols have a variety of physiological activities, including antioxidant, antimicrobial, and anti-inflammatory properties. However, their applications are often limited because due to the instability of polyphenols. Encapsulation technologies can be employed to overcome these problems and increase the utilization of polyphenols. In this article, the utilization of protein-based nanoparticles for encapsulating polyphenols is reviewed due to their good biocompatibility, biodegradability, and functional attributes. Initially, the various kinds of animal and plant proteins available for forming protein nanoparticles are discussed, as well as the fabrication methods that can be used to assemble these nanoparticles. The molecular interaction mechanisms between proteins and polyphenols are then summarized. Applications of protein-based nanoparticles for encapsulating polyphenols are then discussed, including as nutrient delivery systems, in food packaging materials, and in the creation of functional foods. Finally, areas where further research is need on the development, characterization, and application of protein-based polyphenol-loaded nanoparticles are highlighted.

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.

Development of pea protein nanoparticle/hydrolyzed rice glutelin fibril emulsion gels for encapsulation of curcumin

The potential of using emulsion gels stabilized by binary plant protein nanoparticle mixtures for the encapsulation and delivery of lipophilic nutraceuticals was evaluated. The particle characteristics, physical stability, water diffusivity, microrheology, large amplitude oscillating shear (LAOS) properties, and in vitro digestion of emulsion gels prepared by different ratios of hydrolyzed rice glutelin fibrils (HRGFs) and pea protein nanoparticle (PNP) were characterized. The emulsion gel with P/H = 2:1 (0.84 μm) exhibited the best storage stability and freeze-thaw stability, as seen by the smaller oil droplet size (1.02 and 1.42 μm, respectively). Low-field pulsed NMR indicated that the majority of water in samples was highly mobile. All the samples were predominantly elastic-like materials. The P/H 2:1 emulsion gel had the lowest FI value (6.21 × 10-4 Hz), the highest MVI value (5.57 s/nm2), G'/ G″ values and enclosed area, showing that it had denser 3D network structures, higher stiffness values, and a high sensitivity to changes in strain. Additionally, P/H 2:1 emulsion gel had a relatively high lipid digestibility (96.1 %), curcumin bioaccessibility (58.9 %), and curcumin stability (94.2 %). This study showed that emulsion gels stabilized by binary protein nanoparticle mixtures (PNP/HRGF) have potential as edible delivery systems for lipophilic nutraceuticals.

Fabrication of polysaccharide-coated oleanolic acid-curcumin-coassembled nanoparticles (OA/Cur NPs): Enhancement of colloidal stability and water solubility

Natural terpenoid carriers, such as oleanolic acid (OA), can enhance the water solubility and stability of hydrophobic compounds such as curcumin (Cur). However, improving the colloidal stability of nanoparticle emulsions and resolving the redispersion problem of freeze-dried nanoparticle powders remain significant challenges. In this study, we fabricated coassembled oleanolic acid-curcumin nanoparticles (OA/Cur NPs) and applied a polysaccharide surface coating method to improve their colloidal stability and water solubility. The results showed that the optimal ratio of Cur/OA for preparing OA/Cur NPs was 4:10, resulting in a high encapsulation efficiency (EE) of Cur (75.2%). Additionally, TEM, contact angle tests, Turbiscan TOWER optical stability analysis of the polysaccharide-coated OA/Cur NP emulsions and redispersion tests of their lyophilized powders verified the advantages of carboxymethyl chitosan/β-cyclodextrin (CMC/β-CD) coating over other polysaccharides. This study indicated that polysaccharide coating is an effective method for enhancing the colloidal stability, water solubility, and redispersibility of OA/Cur NPs.

Interaction between lactic acid bacteria and Polygonatum sibiricum saponins and its application to microencapsulated co-delivery

This study aimed to investigate the interaction between L.casei and L.bulgaricus with Polygonatum sibiricum saponins (PSS) and to explore the co-microencapsulation to reduce their loss rate during storage and consumption. 1% PSS was added to the culture broth, and it was found that the growth and metabolism of the strains were accelerated, especially in the compound probiotic group, indicating that PSS has potential for prebiotics. LC-MS observed significant differences in the composition and content of saponins in PSS. The metabolomics results suggest that the addition of PSS resulted in significant changes in the metabolites of probiotics. In addition, it was found that the combination of probiotics and PSS may have stronger hypoglycemic ability (ɑ-glucosidase, HepG2). Finally, a co-microencapsulated delivery system was constructed using zein and isomaltooligosaccharide. This system can achieve more excellent resistance of probiotics and PSS in gastrointestinal fluids, effectively transporting both to the small intestine.

Stabilization of zein nanoparticles with tween-80 and fucoidan for encapsulation of eugenol via a nozzle simulation chip

Eugenol (EU), a natural bioactive compound found in various plants, offers numerous health benefits, but its application in the food and pharmaceutical industry is limited by its high volatility, instability, and low water solubility. Therefore, this study aimed to utilize the surface coating technique to develop zein-tween-80-fucoidan (Z-T-FD) composite nanoparticles for encapsulating eugenol using a nozzle simulation chip. The physicochemical characteristics of the composite nanoparticles were examined by varying the weight ratios of Z, T, and FD. Results showed that the Z-T-FD weight ratio of 5:1:15 exhibited excellent colloidal stability under a range of conditions, including pH (2-8), salt concentrations (10-500 mmol/L), heating (80 °C), and storage (30 days). Encapsulation of EU into Z-T-FD nanoparticles (0.5:5:1:15) resulted in an encapsulation efficiency of 49.29 ± 1.00%, loading capacity of 0.46 ± 0.05%, particle size of 205.01 ± 3.25 nm, PDI of 0.179 ± 0.006, and zeta-potential of 37.12 ± 1.87 mV. Spherical structures were formed through hydrophobic interaction and hydrogen bonding, as confirmed by Fourier transform infrared spectroscopy and molecular docking. Furthermore, the EU-Z-T-FD (0.5:5:1:15) nanoparticles displayed higher in vitro antioxidant properties (with DPPH and ABTS radical scavenging properties at 75.28 ± 0.16% and 39.13 ± 1.22%, respectively), in vitro bioaccessibility (64.78 ± 1.37%), and retention rates under thermal and storage conditions for EU compared to other formulations. These findings demonstrate that the Z-T-FD nanoparticle system can effectively encapsulate, protect, and deliver eugenol, making it a promising option for applications in the food and pharmaceutical industries.

Fabrication, Functional Properties, and Potential Applications of Mixed Gellan-Polysaccharide Systems: A Review

Gellan, an anionic heteropolysaccharide synthesized by Sphingomonas elodea, is an excellent gelling agent. However, its poor mechanical strength and high gelling temperature limit its application. Recent studies have reported that combining gellan with other polysaccharides achieves desirable properties for food- and biomaterial-related applications. This review summarizes the fabrication methods, functional properties, and potential applications of gellan-polysaccharide systems. Starch, pectin, xanthan gum, and konjac glucomannan are the most widely used polysaccharides in these composite systems. Heating-cooling and ionic-induced cross-linking approaches have been used in the fabrication of these systems. Composite gels fabricated using gellan and various polysaccharides exhibit different functional properties, possibly because of their distinct molecular interactions. In terms of applications, mixed gellan-polysaccharide systems have been extensively used in texture modification, edible coatings and films, bioactive component delivery, and tissue-engineering applications. Further scientific studies, including structural determinations of mixed systems, optimization of processing methods, and expansion of applications in food-related fields, are needed.

Enhanced bioavailability of curcumin amorphous nanocomposite prepared by a green process using modified starch

Curcumin (Cur), a bioactive compound extracted from plants, has attracted widespread attention due to its multiple pharmacological activities. However, the low bioavailability due to the inherent limitations in water solubility, chemical stability, and permeability poses great challenges for realizing its clinical potentials. In the current study, octenyl succinic anhydride-modified starch (OSA-S), a renewable and biodegradable biopolymer, was employed to fabricate Cur amorphous composite nanoparticles (Cur/OSA-S NPs) through a solvent-free pH-driven method with the aim to enhance Cur's bioavailability by improving its solubility and stability. Cur/OSA-S NPs, with mean sizes of about 128.9 ± 8.6 nm, encapsulation efficiencies of about 90.0 %, and the drug loading capacities around 51.0 ± 0.2 %, were successfully prepared. Cur was found to be dispersed within the composite nanoparticles in amorphous state as confirmed by the XRD and DSC characterizations. In addition, Cur/OSA-S NPs offers excellent storage, thermal and light stability, excellent re-dispersibility, and approximately 92 times better solubility than the original Cur. Furthermore, studies of dissolution and the parallel artificial membrane permeability assay (PAMPA) confirmed enhanced dissolution rates and in vitro permeabilities of Cur/OSA-S NPs. Cancer cell viability and uptake experiments revealed that Cur/OSA-S NPs possessed more potent inhibitory effects on cancer cell proliferation compared to the raw Cur. The results obtained from the current study demonstrated the effectiveness of OSA-S for manufacturing Cur amorphous composite nanoparticles with enhanced solubility, stability, and permeability, which might be valuable for further development of Cur based products for treatment of various diseases.

Research advances in Zein-based nano-delivery systems

Zein is the main vegetable protein from maize. In recent years, Zein has been widely used in pharmaceutical, agriculture, food, environmental protection, and other fields because it has excellent biocompatibility and biosafety. However, there is still a lack of systematic review and research on Zein-based nano-delivery systems. This paper systematically reviews preparation and modification methods of Zein-based nano-delivery systems, based on the basic properties of Zein. It discusses the preparation of Zein nanoparticles and the influencing factors in detail, as well as analyzing the advantages and disadvantages of different preparation methods and summarizing modification methods of Zein nanoparticles. This study provides a new idea for the research of Zein-based nano-delivery system and promotes its application.

Revolutionizing Cancer Treatment: The Promising Horizon of Zein Nanosystems

Various nanomaterials have recently become fascinating tools in cancer diagnostic applications because of their multifunctional and inherent molecular characteristics that support efficient diagnosis and image-guided therapy. Zein nanoparticles are a protein derived from maize. It belongs to the class of prolamins possessing a spherical structure with conformational properties similar to those of conventional globular proteins like ribonuclease and insulin. Zein nanoparticles have gained massive interest over the past couple of years owing to their natural hydrophilicity, ease of functionalization, biodegradability, and biocompatibility, thereby improving oral bioavailability, nanoparticle targeting, and prolonged drug administration. Thus, zein nanoparticles are becoming a promising candidate for precision cancer drug delivery. This review highlights the clinical significance of applying zein nanosystems for cancer theragnostic─moreover, the role of zein nanosystems for cancer drug delivery, anticancer agents, and gene therapy. Finally, the difficulties and potential uses of these NPs in cancer treatment and detection are discussed. This review will pave the way for researchers to develop theranostic strategies for precision medicine utilizing zein nanosystems.

Nanoencapsulation and delivery of bioactive ingredients using zein nanocarriers: approaches, characterization, applications, and perspectives

Zein has garnered widespread attention as a versatile material for nanosized delivery systems due to its unique self-assembly properties, amphiphilicity, and biocompatibility characteristics. This review provides an overview of current approaches, characterizations, applications, and perspectives of nanoencapsulation and delivery of bioactive ingredients within zein-based nanocarriers. Various nanoencapsulation strategies for bioactive ingredients using various types of zein-based nanocarrier structures, including nanoparticles, nanofibers, nanoemulsions, and nanogels, are discussed in detail. Factors affecting the stability of zein nanocarriers and characterization methods of bioactive-loaded zein nanocarrier structures are highlighted. Additionally, current applications of zein nanocarriers loaded with bioactive ingredients are summarized. This review will serve as a guide for the selection of appropriate nanoencapsulation techniques within zein nanocarriers and a comprehensive understanding of zein-based nanocarriers for specific applications in the food, pharmaceutical, cosmetic, and agricultural industries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01489-6.

Improved bioavailability and antioxidation of β-carotene-loaded biopolymeric nanoparticles stabilized by glycosylated oat protein isolate

The limited bioavailability of β-carotene hinders its potential application in functional foods, despite its excellent antioxidant properties. Protein-based nanoparticles have been widely used for the delivery of β-carotene to overcome this limitation. However, these nanoparticles are susceptible to environmental stress. In this study, we utilized glycosylated oat protein isolate to prepare nanoparticles loaded with β-carotene through the emulsification-evaporation method, aiming to address this challenge. The results showed that β-carotene was embedded into the spherical nanoparticles, exhibiting relatively high encapsulation efficiency (86.21 %) and loading capacity (5.43 %). The stability of the nanoparticles loaded with β-carotene was enhanced in acidic environments and under high ionic strength. The nanoparticles offered protection to β-carotene against gastric digestion and facilitated its controlled release (95.76 % within 6 h) in the small intestine, thereby leading to an improved in vitro bioavailability (65.06 %) of β-carotene. This improvement conferred the benefits on β-carotene nanoparticles to alleviate tert-butyl hydroperoxide-induced oxidative stress through the upregulation of heme oxygenase-1 and NAD(P)H quinone dehydrogenase 1 expression, as well as the promotion of nuclear translocation of nuclear factor-erythroid 2-related factor 2. Our study suggests the potential for the industry application of nanoparticles based on glycosylated proteins to effectively deliver hydrophobic nutrients and enhance their application.

Stability and encapsulation properties of daidzein in zein/carrageenan/sodium alginate nanoparticles with ultrasound treatment

This study aimed to prepare carrageenan/sodium alginate double-stabilized layers of zein nanoparticles loaded with daidzein using ultrasound technology to investigate the effect of ultrasound treatment on the stability of composite nanoparticles and encapsulation of daidzein. Compared with composite nanoparticles without ultrasound treatment, the encapsulation efficiency of nanoparticles was increased (90.36 %) after ultrasound treatment (320 W, 15 min). Ultrasound treatment reduced the particle size and PDI of nanoparticles and improved the stability and solubility of nanoparticles. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed that the nanoparticles treated with ultrasound were smooth spherical and uniformly distributed. Fourier transform infrared spectroscopy (FTIR) results showed that the main forces that form nanoparticles are hydrogen bonding, electrostatic interactions and hydrophobic interactions. Fluorescence and CD chromatography showed that ultrasound treatment alters the secondary structure of zein and maintains nanoparticle stability. Encapsulation of daidzein in nanocarriers with ultrasound treatment can effectively scavenge DPPH and ABTS free radicals, improve antioxidant activity, and realize the slow release of daidzein in the gastrointestinal tract. The results showed that ultrasonication helps the construction of hydrophobic bioactives delivery carriers and provides better protection for unstable bioactives.

Preparation and characterization of dextran-zein-curcumin nanoconjugate for enhancement of curcumin bioactivity

Curcumin is one of the most important polyphenolic nutrients in pharmaceutical industries. Unfortunately, its poor solubility and bioavailability have hampered its clinical application. To improve curcumin solubility and bioavailability, a natural nanocarrier made from protein-polysaccharide conjugate has been developed. Following antisolvent precipitation method, zein (Z) nanoparticles coated with dextran sulphate (DS) have been fabricated as curcumin (C) nanocarrier (DSZCNPs). The physicochemical properties of the nanoconjugate were measured using different techniques. Morphologically, DSZCNPs appeared spherical and monodispersed in scanning electron microscope (SEM) and transmission electron microscope (TEM) images. Curcumin encapsulation efficiency was ≈ 96%. DSZCNPs size was 180 nm and the polydispersity index value (PDI) 0.28. Zeta potential for DSZCNPs was -28.5 mV. DSZCNPs showed stability either for shelf storage (100 days) or at different pHs. Furthermore, DSZCNPs protected zein nanoparticles degradation in gastric environment and achieved controlled curcumin release in intestinal environment. DSZCNPs greatly enhanced the antioxidant activity of curcumin as demonstrated by DPPH assay. DSZCNPs had significant results in the reduction of colony forming unit (CFU%) against the tested microbes when compared with free curcumin. Also, the anticancer activity of DSZCNPs and free curcumin against hepatocellular carcinoma cells (HepG2) were assessed by MTT assay. IC50 for DSZCNPs was 13 µg/ml compared to 50 µg/ml for free curcumin indicating the therapeutic impact of DSZCNPs over free curcumin.Based on the above results, the developed zein-dextran nanocomplex exhibited high stability and improved the efficacy and bioactivity of curcumin suggesting its potential utility as nanovehicle for the hydrophobic drug curcumin.

An overview of tea saponin as a surfactant in food applications

The residue of Camellia seeds after oil extraction contains many bioactive ingredients, including tea saponin. Tea saponin has many pharmacological effects and is an excellent nonionic surfactant. The development of natural surfactants has become a hot topic in food research. This review gathers the applications of tea saponin as a surfactant in food. It focuses on the application of tea saponin in emulsions, delivery systems, extraction and fermentation, as well as the challenges and development prospects in food applications. Tea saponin shows great potential as a surfactant in food applications, which can replace some synthetic surfactants. The full utilization of tea saponin improves the comprehensive utilization value of Camellia seed residue, contributes to the sustainable development of Camellia industry and avoids resource waste.

Construction of a Ternary Composite Colloidal Structure of Zein/Soy Protein Isolate/Sodium Carboxymethyl Cellulose to Deliver Curcumin and Improve Its Bioavailability

This work presents the fabrication of ternary nanoparticles (Z/S/C NPs) comprising zein (Z), soy protein isolate (SPI) and carboxymethylcellulose sodium (CMC-Na) through a pH-driven method. The results showed that the smallest particle size (71.41 nm) and the most stable zeta potential, measuring -49.97 mV, were achieved with the following ratio of ternary nanoparticles Z/SPI/CMC-Na (2:3:3). The surface morphology of the nanoparticles was further analyzed using transmission electron microscopy, and the synthesized nanoparticles were utilized to encapsulate curcumin (Cur), a hydrophobic, bioactive compound. The nanoparticles were characterized using a particle size analyzer, infrared spectroscopy, and X-ray diffraction (XRD) techniques. The results revealed that the formation of nanoparticles and the encapsulation of Cur were driven by electrostatic, hydrogen-bonding and hydrophobic interactions. The drug loading efficiency (EE%) of Z/S/C-cur nanoparticles reached 90.90%. The Z/S/C ternary nanoparticles demonstrated enhanced storage stability, photostability and simulated the gastrointestinal digestion of Cur. The release of Cur and variations in the particle size of nanoparticles were investigated across different stages of digestion. The biocompatibility of the Z/S/C ternary nanoparticles was assessed by conducting cell viability assays on HepG2 and L-O2 cells, which showed no signs of cytotoxicity. These results suggested that the ternary composite nanoparticles have potential in delivering nutritional foods and health-promoting bioactive substances.

Characterization, stability and antioxidant activity of curcumin nanocomplexes with soy protein isolate and pectin

Curcumin (Cur) has antioxidant, anti-inflammatory and other biological activities, but its poor stability, low water solubility and other defects limit the application. Herein, Cur was nanocomposited with soy isolate protein (SPI) and pectin (PE) for the first time and its characterization, bioavailability and antioxidant activity were discussed. The optimal encapsulation process of SPI-Cur-PE was as follow: the addition amount of PE was 4 mg, Cur was 0.6 mg and at pH of 7. It was observed by SEM that SPI-Cur-PE were partially aggregated. The average particle size of SPI-Cur-PE was 210.1 nm and the zeta potential was -31.99 mV. Through XRD, FT-IR and DSC analysis, the SPI-Cur-PE was formed through hydrophobic interaction and electrostatic interaction. The SPI-Cur-PE released more slowly in simulated gastrointestinal treatment and displayed higher photostability and thermal stability. SPI-Cur-PE, SPI-Cur and free Cur had scavenging activities for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals.

A review of curcumin in food preservation: Delivery system and photosensitization

As a natural polyphenol, curcumin has been used as an alternative to synthetic preservatives in food preservation. Different from previous reviews that mainly focus on the pH-responsive discoloration of curcumin to detect changes in food quality in real time, this paper focuses on the perspective of the delivery system and photosensitization of curcumin for food preservation. The delivery system is an effective means to overcome the challenges of curcumin like instability, hydrophobicity, and low bioavailability. Curcumin as a photosensitizer can effectively sterilize to preserve food. The practical fresh-keeping effects of the delivery system and photosensitization of curcumin on foods (fruits/vegetables, animal-derived food, and grain) were summarized comprehensively, including shelf-life extension, maintenance of physicochemical properties, nutritional quality, and sensory. Future research should focus on the development of novel curcumin-loaded materials used for food preservation, and most importantly, the biosafety and accumulation toxicity associated with these materials should be explored.

Food emulsifier based on the interaction of casein and butyrylated dextrin for improving stability and emulsifying properties

Green hydrophobically modified butyrylated dextrin (BD) was used to modulate casein (CN). The CN/BD complex nanoparticles were formed at different CN-to-BD mass ratios based on a pH-driven technology. The interaction force, stability, and emulsifying properties of complex nanoparticles were investigated. The nanoparticles had a negative charge and a small particle size (160.03, 152.6, 155.9, 206.13, and 231.67 nm) as well as excellent thermal stability and environmental stability (pH 4.5, 5.5, 6.6, 7.5, 8.5, and 9.5; ionic strength, 50, 100, 200, and 500 mM). Transmission electron microscopy demonstrated the successful preparation of complex nanoparticles and their spherical shape. Fourier transform infrared spectroscopy, fluorescence spectroscopy, and dissociation analysis results showed that the main driving forces of formed CN/BD nanoparticles were hydrogen bonding and hydrophobic interaction. Furthermore, the CN/BD nanoparticles (CN/BD mass ratio, 1:1; weight/weight) exhibited the lowest creaming index, and optical microscopy showed that it has the most evenly dispersed droplets after 7 d of storage, which indicates that the CN/BD nanoparticles had excellent emulsifying properties. Butyrylated dextrin forms complex nanoparticles with CN through hydrogen bonding and hydrophobic interaction to endow CN with superior properties. The results showed that it is possible to use pH-driven technology to form protein-polysaccharide complex nanoparticles, which provides some information on the development of novel food emulsifiers based on protein-polysaccharide nanoparticles. The study provided significant information on the improvement of CN properties and the development of emulsions based on CN.

Curcumin encapsulated zein/caseinate-alginate nanoparticles: Release and antioxidant activity under in vitro simulated gastrointestinal digestion

Curcumin-loaded zein/sodium caseinate-alginate nanoparticles were successfully fabricated using a pH-shift method/electrostatic deposition method. These nanoparticles produced were spheroids with a mean diameter of 177 nm and a zeta-potential of -39.9 mV at pH 7.3. The curcumin was an amorphous, and the content in the nanoparticles was around 4.9% (w/w) and the encapsulation efficiency was around 83.1%. Aqueous dispersions of the curcumin-loaded nanoparticles were resistant to aggregation when subjected to pH changes (pH 7.3 to 2.0) and sodium chloride addition (1.6 M), which was mainly attributed to the strong steric and electrostatic repulsion provided by the outer alginate layer. An in vitro simulated digestion study showed that the curcumin was mainly released during the small intestine phase and that its bioaccessibility was relatively high (80.3%), which was around 5.7-fold higher than that of non-encapsulated curcumin mixed with curcumin-free nanoparticles. In the cell culture assay, the curcumin reduced reactive oxygen species (ROS), increased superoxide dismutase (SOD) and catalase (CAT) activity, and reduced malondialdehyde (MDA) accumulation in hydrogen peroxide-treated HepG2 cells. The results suggested that nanoparticles prepared by pH shift/electrostatic deposition method are effective at delivering curcumin and may be utilized as nutraceutical delivery systems in food and drug industry.

Zein-based nanoparticles: Preparation, characterization, and pharmaceutical application

Zein, as one of the natural and GRAS proteins in plant, is renewable, nontoxic, biocompatible and biodegradable. Over the past decade, many research efforts have been devoted to zein-based biomaterials for several industrial applications. Combining with research experiences in our research group, the preparation methods, characterizations and pharmaceutical applications of zein-based nanoparticles were summarized in this review. Zein NPs with different particle nanostructures have been prepared by chemical crosslinking, desolvating, dispersing and micromixing strategies. The pharmaceutical applications of zein NPs are mainly focus on the drug delivery. Zein NPs can improve the drug stability, increase the oral bioavailability, control the drug release and enhance the drug targeting, thereby improving the pharmaceutical effect effectively. More efforts are required to analyze the relationship among preparation methods, particle nanostructures and pharmaceutical properties in virtue of quality by design approach, and further promote the scale-up production and clinical application of zein NPs.

Fabrication, Evaluation, and Antioxidant Properties of Carrier-Free Curcumin Nanoparticles

Curcumin (Cur), a natural hydrophobic polyphenolic compound, exhibits multiple beneficial biological activities. However, low water solubility and relative instability hinder its application in food fields. In this study, carrier-free curcumin nanoparticles (CFC NPs) were prepared by adding the DMSO solution of Cur into DI water under continuous rapid stirring. The morphology of CFC NPs was a spherical shape with a diameter of 65.25 ± 2.09 nm (PDI = 0.229 ± 0.107), and the loading capacity (LC) of CFC NPs was as high as 96.68 ± 0.03%. The thermal property and crystallinity of CFC NPs were investigated by XRD. Furthermore, the CFC NPs significantly accelerated the release of Cur in vitro owing to its improved water dispersibility. Importantly, CFC NPs displayed significantly improved DPPH radical scavenging activity. Overall, all these results suggested that CFC NPs would be a promising vehicle to widen the applications of Cur in food fields.

Efficient Utilization of Tea Resources through Encapsulation: Dual Perspectives from Core Material to Wall Material

With the high production and consumption of tea around the world, efficient utilization of tea byproducts (tea pruning, tea residues after production, and drinking) is the focus of improving the economy of the tea industry. This review comprehensively discusses the efficient utilization of tea resources by encapsulation from the dual perspectives of core material and wall material. The core material is mainly tea polyphenols, followed by tea oils. The encapsulation system for tea polyphenols includes microcapsules, nanoparticles, emulsions, gels, conjugates, metal-organic frameworks, liposomes, and nanofibers. In addition, it is also diversified for the encapsulation of tea oils. Tea resources as wall materials refer to tea saponins, tea polyphenols, tea proteins, and tea polysaccharides. The application of the tea-based delivery system widely involves functionally fortified food, meat preservation, film, medical treatment, wastewater treatment, and plant protection. In the future, the coencapsulation of tea resources as core materials and other functional ingredients, the precise targeting of these tea resources, and the wide application of tea resources in wall materials need to be focused on. In conclusion, the described technofunctional properties and future research challenges in this review should be followed.

Protective Effect of Tea Saponins on Alcohol-Induced Gastric Mucosal Injury in Mice

Excessive alcohol consumption harms the human body, particularly the digestive system, by causing damage to the gastric mucosa. Tea saponin is a natural active substance extracted from tea tree seeds that has gastroprotective potential against alcohol-induced mucosal damage. However, the protective mechanism of tea saponins is not fully understood. The current study aimed to explore the protective mechanism of tea saponins against alcohol-induced gastric mucosal injury in mice. Histopathological changes, immunohistochemistry, immunoblotting, and gastric mucosa-related cytokine levels were analyzed in three groups of male mice: model, control, and tea saponin-treated. Compared to the model group, the tea saponin group prominently ameliorated alcohol-induced gastric mucosal injury by improving cell necrosis, inflammatory cell infiltration, and edema. Downregulation of inflammation-related factors cluster of differentiation 68 (CD68), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) was also found in the tea saponin group. These results suggest that tea saponins have a protective effect against alcohol-induced gastric mucosal damage in mice. Therefore, tea saponin may serve as a food additive for gastric mucosal protection.

Delivery of curcumin by shellac encapsulation: Stability, bioaccessibility, freeze-dried redispersibility, and solubilization

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Shellac can nano-encapsulate curcumin by pH cycle.

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The starting point of the design is economy, simplicity, energy saving and safety.

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High loading capacity of curcumin is the unique advantage of shellac nanoparticles.

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The nanoparticles had good physicochemical stability and bioaccessibility.

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The redispersibility is proportional to the mass ratio of shellac-to-curcumin.

Curcumin is an active ingredient with multiple functions, however, its application is limited by its low stability, bioaccessibility, freeze-dried redispersibility, and solubilization. The work aims to improve the application of curcumin (Cur) by encapsulation. Shellac was the wall material inspired by its pH-dependent deprotonation and amphiphilic nature to form nanoparticles. The curcumin/shellac nanoparticles (S/Cur) exhibited a bright spot of high loading capacity (the maximum of higher than 70 %), while still having high encapsulation efficiency (the minimum of higher than 85 %). Transmission electron microscopy showed that S/Cur was a spherical structure. It exhibited good physical stability, including pH (4.0–8.0), ionic strength (NaCl, < 900 mM), thermo stability (80 ℃, 180 min), and storage stability (light and dark, 4 and 25 ℃, 20 days). Meanwhile, the chemical stability was increased by encapsulation. Furthermore, the bioaccessibility of Cur was improved to 75.95 %, which is attributed to the pH response of shellac. Additionally, S/Cur had freeze-dried redispersibility and solubilization, which is proportional to the mass ratio of shellac-to-Cur. The mechanism of S/Cur formation involved hydrophobic interaction and hydrogen bonds, and the nanoconfined Cur was amorphous.

Fabrication, Characterization, and Antimicrobial Activity of Carvacrol-Loaded Zein Nanoparticles Using the pH-Driven Method

To reduce the application of synthetic additives in the field of food preservation, this study utilized carvacrol as an antibacterial agent, and zein and sodium caseinate as carriers, to prepare composite nanoparticles loaded with carvacrol by the pH-driven method. The composite nanoparticles of zein/sodium caseinate had an excellent encapsulation efficiency (77.96~82.19%) for carvacrol, and it had remarkable redispersibility. The results of Fourier transform infrared spectroscopy showed that the formation of the composite nanoparticles mainly depended on the hydrogen bond and the hydrophobic zone force, and thermal gravimetric analysis showed that carvacrol was loaded successfully into nanoparticles, and loading efficiency reached 24.9%. Scanning electron microscopy showed that the composite nanoparticles were spherical, with a particle size range of 50~200 nm, and through the free radical scavenging method and the plate counting method to confirm the particle has stronger antioxidant and antibacterial properties, and with the composite nanoparticles with poly (vinyl alcohol) film applied to the preservation of banana together, it was found that PVA film containing 5 wt% CA-loaded composite NPs can significantly extend the storage period of banana. Therefore, when the composite nanoparticles were applied to food packaging, they could effectively inhibit food spoilage and lengthen the shelf life of food, which displays potential application prospects in the food industry.

pH-driven self-assembly of alcohol-free curcumin-loaded zein-propylene glycol alginate complex nanoparticles

This study aimed to prepare alcohol-free curcumin-loaded zein-propylene glycol alginate (zein-PGA-Cur) nanoparticles using the pH-driven method to enhance the bioavailability and physicochemical stability of curcumin. The prepared zein-PGA-Cur nanoparticles exhibited a small size (360 nm) and negative zeta-potential (-5.8 mV), as well as excellent physical stability, under storage conditions of pH 4.0 and temperature at 4 °C for 30 days. In addition, the Fourier transform infrared spectroscopy results demonstrated that the main interactions of pH-driven for the formation of zein-PGA-Cur nanoparticles were hydrogen bonding, hydrophobic, and electrostatic interactions. Fluorescence spectroscopy revealed that the curcumin-induced fluorescence quenching of zein was static. Circular Dichroism spectroscopy demonstrated that the pH-driven method mainly decreased the β-sheet structure of zein from 3.9 % to 1.4 %. Furthermore, the HT-29 colorectal adenocarcinoma cells viability experiments revealed that the prepared zein-PGA-Cur nanoparticles exhibited excellent biocompatibility. In vivo rat experiments also demonstrated that the prepared nanoparticles resulted in a higher plasma concentration of curcumin, representing a 7.2-fold enhancement in bioavailability compared with pure curcumin crystals. The findings of this study will provide a green and energy-saving method for the development of insoluble drug self-assembly systems and promote their wider applications in drug delivery.

Efficient encapsulation of curcumin into spent brewer's yeast using a pH-driven method

Curcumin (CUR) was encapsulated into yeast cells (YCs) through a pH-driven method with a 5.04-fold increase in loading capacity and a 43.63-fold reduction in incubation time compared to the conventional diffusion method. Optimal encapsulation was obtained when the mass ratio of CUR to YCs was 0.1, and the loading capacity and encapsulation efficiency were 8.07% and 80.66%, respectively. Encapsulation of CUR into YCs was confirmed by fluorescence microscopy, differential scanning calorimetry, and thermogravimetric analysis. Fourier transform infrared spectroscopy and X-ray diffraction further demonstrated that the encapsulated CUR was interacted with mannoprotein and β-glucan of the cell wall network through hydrophobic interaction and hydrogen bond in amorphous state. The in vitro bioaccessibility of YCs-loaded CUR was significantly increased by 6.05-fold. The enhanced encapsulation efficiency and rapid encapsulation process proposed in this study could facilitate YCs-based microcarriers to encapsulate bioactive substances with higher bioaccessibility.

Zein Microparticles and Nanoparticles as Drug Delivery Systems

Zein is a natural, biocompatible, and biodegradable polymer widely used in the pharmaceutical, biomedical, and packaging fields because of its low water vapor permeability, antibacterial activity, and hydrophobicity. It is a vegetal protein extracted from renewable resources (it is the major storage protein from corn). There has been growing attention to producing zein-based drug delivery systems in the recent years. Being a hydrophobic biopolymer, it is used in the controlled and targeted delivery of active principles. This review examines the present-day landscape of zein-based microparticles and nanoparticles, focusing on the different techniques used to obtain particles, the optimization of process parameters, advantages, disadvantages, and final applications.

Properties of selenium nanoparticles stabilized by Lycium barbarum polysaccharide-protein conjugates obtained with subcritical water

Selenium nanoparticles (SeNPs) in an aqueous solution have poor stability and tend to aggregate when stored for a long time. In the present study, SeNPs were stabilized by using Lycium barbarum polysaccharide (LBP) and Lycium barbarum protein (LBPr) conjugates (LBPP) as a stabilizer and dispersing agent. Particularly, the LBPP₁ was obtained with subcritical water treatment. In addition, the physical stability, re-dispersity and antitumor activity of LBPP₁-SeNPs were investigated. The results showed the particle size of LBPP₁-SeNPs was maintained at 111.5-117 nm, which was stable at PH 6, 4 °C and darkness for at least 40 days. Besides, the result of TEM showed that the dispersion of LBPP₁-SeNPs had more clear layers and smoother surfaces. Moreover, LBPP₁-SeNPs had excellent re-dispersibility and exhibited a significant inhibitory effect on HepG-2 cells and Caco-2 cells, respectively (p < 0.05). Therefore, LBPP₁-SeNPs can be used as potential selenium nutritional supplements for food and medical applications.

A review of factors affecting the stability of zein-based nanoparticles loaded with bioactive compounds: from construction to application

Zein-based nanoparticles loaded with bioactive compounds have positive prospects in the food industry, but an important limiting factor for development is colloidal instability. Currently, extensive researches are focused on solving the instability of zein nanoparticles, but since the beginning of the studies, there has not been a summary of the factors affecting the stability of zein-based nanoparticles. In the present work, the factors were reviewed comprehensively from the perspective of carrier construction and application evaluation. The former mainly includes type, quantity, and characteristics of biopolymer, the mass ratio of biopolymer/bioactive compound to zein, blending sequence of biopolymer, and location of encapsulated bioactive compounds. The latter mainly includes pH, heating, ionic strength, storage, freeze-drying, and gastrointestinal digestion. The former is the prerequisite for the success of the latter. The challenge is that stability research is limited to the laboratory level, and it is difficult to ensure that the stability results are suitable for commercial food matrices due to their complexity. At the laboratory level, the future trends are the influence of external energy and the cross-complexity and uniformity of stability research. The review is expected to provide systematic understanding and guidance for the development of zein-based nanoparticles stability.

Fabrication and characterization of core-shell gliadin/tremella polysaccharide nanoparticles for curcumin delivery: Encapsulation efficiency, physicochemical stability and bioaccessibility

The objectives of the present study were to synthesize gliadin/tremella polysaccharide nanoparticles (Gli/TP NPs) as well as curcumin-loaded gliadin/tremella polysaccharide nanoparticles (Cur-Gli/TP NPs) and evaluate the encapsulation efficiency (EE), physicochemical stability and bioaccessibility of Cur-Gli/TP NPs. The physicochemical properties of the nanoparticles depended on the mass ratio of Gli to TP and pH values. The characterization of the Gli/TP NPs indicated that the prepared nanoparticles were the most stable when the Gli/TP mass ratio was 1:1 and pH was at 4.0-7.0. Afterward, prepared Cur-Gli/TP NPs at different pH values were studied. Compared with the EE of Cur (58.2%) in Cur-Gli NPs at pH 5.0, the EE of Cur (90.6%) in Cur-Gli/TP NPs at pH 5.0 was increased by 32.4%. Besides, the Cur-Gli/TP NPs possessed excellent physical stability, photostability, thermal stability and re-dispersibility than Cur-Gli NPs. Furthermore, the bioaccessibility of Cur reached 83.5% after encapsulation of Cur into Gli/TP NPs after in vitro digestion, indicating that Cur-Gli/TP NPs could improve curcumin bioaccessibility significantly. In summary, this study demonstrates that the new food-grade Gli/TP NPs possess high encapsulation efficiency, excellent stability and prominent nutraceutical bioaccessibility. Meanwhile, it contributes to expanding the application of TP in food-grade delivery systems.

pH-driven self-assembly of alcohol-free curcumin-loaded propylene glycol alginate nanoparticles

The purpose of this paper was to explore the application of propylene glycol alginate (PGA) alone in alcohol-free curcumin-loaded nanoparticles (PGA/Cur) prepared by a pH-driven method to solve the curcumin shortcomings of low water solubility, stability and bioavailability. One of the bright spots of PGA/Cur was its extremely high loading capacity. PGA/Cur formed a spherical structure mainly by hydrophobic interaction and hydrogen bonding, making curcumin amorphous. PGA/Cur exhibited stability at pH 4.0-8.0 due to its high surface charges. PGA/Cur still showed a unimodal size distribution even under 3000 mM ionic strength. Heating caused uneven size distribution, but the smaller size still presented its thermostability. PGA/Cur exhibited good physical stability and slowed down the curcumin degradation with t_1/2 of 37.47 days during storage. PGA/Cur could maintain structural integrity in gastric acid and released curcumin in the intestine, thus improving the bioaccessibility of curcumin. Additionally, PGA/Cur displayed the solubilization after lyophilization.

Nanoencapsulation of apigenin with whey protein isolate: physicochemical properties, in vitro activity against colorectal cancer cells, and bioavailability

Incorporating lipophilic phytochemicals with anti-cancer activities in functional beverages requires an appropriate nanoencapsulation technology. The present objective was to encapsulate apigenin with whey protein isolate (WPI) utilizing a pH-cycle method and subsequently characterize physicochemical properties, the in vitro anticancer activities against human colorectal HCT-116 and HT-29 cancer cells, and the in vivo bioavailability. Up to 2.0 mg/mL of apigenin was nanoencapsulated with 1.0 mg/mL WPI, with an encapsulation efficiency of up to 98.15% and loading capacity of up to 196.21 mg/g-WPI. Nanodispersions were stable during storage, and apigenin became amorphous after encapsulation. Nanoencapsulation and in vitro digestion did not reduce the anti-proliferative activity of apigenin. Nanoencapsulation of apigenin enhanced the cellular uptake, the pro-apoptotic effects, and the bioavailability in the mice's blood and colon mucosa when comparing to the unencapsulated apigenin. Therefore, the present work may be significant to incorporate lipophilic phytochemicals in functional beverages for disease prevention.

Tremella polysaccharides-coated zein nanoparticles for enhancing stability and bioaccessibility of curcumin

The purpose of the present research was to examine the ability of Tremella polysaccharide (TP) to stabilize zein nanoparticles (zein NPs) and appraise the performance of zein/Tremella polysaccharide nanoparticles (zein/TP NPs) in terms of encapsulating and delivering curcumin. In this study, the zein/TP NPs were fabricated based on the anti-solvent precipitation method, which were used to protect and deliver curcumin. The results suggested that TP could be deposited on the surface of zein NPs by virtue of electrostatic interaction, so as to improve the hydrophilicity of zein, provide better protection for curcumin and assemble more stable nanoparticles. Compared with zein NPs (54.73%), the zein/TP NPs exhibited higher encapsulation efficiency of curcumin (93.34%) and excellent re-dispersibility. Furthermore, the retention rate of curcumin encapsulated in zein/TP NPs reached 80.78% and 90.74% after UV irradiation and 80 °C heat treatment for 2 h, respectively, which proved that the addition of TP significantly improved the stability of curcumin. Meanwhile, in vitro digestion study demonstrated that the bioaccessibility of curcumin encapsulated in zein/TP NPs increased by 37.36% compared with in zein NPs. Therefore, the zein/TP NPs may be served as an effective and potential carrier for the delivery of nutraceuticals.

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Zein/tremella polysaccharide nanoparticles (zein/TP NPs) were fabricated via anti-solvent deposition method.

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Deposition of TP on zein nanoparticles improved the encapsulation efficiency of curcumin.

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The mass ratio of zein to TP influenced physicochemical stabilities of nanoparticles.

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Curcumin loaded in zein/TP NPs showed superior photostability and thermal stability.

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Zein/TP NPs enhanced the bioaccessibility of curcumin in vitro gastrointestinal fluids.

Construction of biopolymer-based nanoencapsulation of functional food ingredients using the pH-driven method: a review

Biopolymer-based nanoencapsulation presents great performance in the delivery of functional food ingredients. In recent years, the pH-driven method has received considerable attention due to its unique characteristics of low energy and organic solvent-free during the construction of biopolymer-based nanoencapsulation. This review summarized the fundamental knowledge of pH-driven biopolymer-based nanoencapsulation. The principle of the pH-driven method is the protonation reaction of functional food ingredients that change with pH. The stability of functional food ingredients in an alkaline environment is a prerequisite for the adoption of this method. pH regulator is also an important influencing factor. Different coating materials used to the pH-driven nanoencapsulation were discussed, including single and composite materials, mainly focusing on proteins. Besides, the application evaluations of pH-driven nanoencapsulation in food were analyzed. The future development trends will be the influence of pH regulators on the carrier, the design of new non-protein-based carriers, the quantification of driving forces, the absorption mechanism of encapsulated nutrients, and the molecular interaction between the wall material and the intestinal mucosa. In conclusion, pH-driven biopolymer-based nanoencapsulation of functional food ingredients will have broad prospects for development.

Formation and Physical Stability of Zanthoxylum bungeanum Essential Oil Based Nanoemulsions Co-Stabilized with Tea Saponin and Synthetic Surfactant

The purpose of this work was to evaluate the possibility of adding tea saponin (TS) to reduce the synthetic surfactant concentration, and maintain or improve the shelf stability of nanoemulsions. The Zanthoxylum bungeanum essential oil (2.5 wt%) loaded oil-in-water nanoemulsions were co-stabilized by Tween 40 (0.5–2.5 wt%) and TS (0.1–5 wt%). A combination of several analytical techniques, such as dynamic laser scattering, interfacial tension, zeta potential, and transmission electron microscope, were used for the characterization of nanoemulsions. Low levels of TS (0.1–0.5 wt%) with Tween 40 had significant effects on the emulsification, and a nanoemulsion with the smallest droplet diameter of 89.63 ± 0.67 nm was obtained. However, in the presence of high TS concentration (0.5–5 wt%), micelles generated by the non-adsorbed surfactants in the aqueous lead to droplets growth. In addition, the combinations of Tween 40 and TS at the high level (>3.5 wt%) exerted a synergistic effect on stabilizing the nanoemulsions and preventing both Ostwald ripening and coalescence. The negative charged TS endowed the droplets with electrostatic repulsion and steric hinderance appeared to prevent flocculation and coalescence. These results would provide a potential application of natural TS in the preparation and stabilization of nanoemulsions containing essential oil.

Self-coacervation of carboxymethyl chitosan as a pH-responsive encapsulation and delivery strategy

Carboxymethyl chitosan (CMCS)-based complex coacervate has attracted much attention in drug oral delivery due to its pH-responsive property. As a unique ampholyte polymer, the self-coacervation of CMCS has great research potential. In this work, CMCS self-coacervates were prepared by adjusting the pH of the CMCS aqueous solution close to its isoelectric point. The Fourier-transformed infrared spectroscopy (FTIR) results revealed that electrostatic interactions, hydrogen bonding, and hydrophobic interactions were involved in the self-coacervation of CMCS. The obtained self-coacervates presented a dense surface structure, and were stable at a wide pH range of 3.0-6.0, and gradually dissolved under basic conditions. Although self-coacervation decreased the crystallinity and thermal stability of CMCS, the obtained coacervates showed excellent pH-responsive properties and ionic strength stability. We also investigated its potential in lactoferrin (LF) encapsulation and oral delivery. The CMCS self-coacervates exhibited a high encapsulation efficiency (EE) of 94.79 ± 0.49% and loading capacity (LC) of 26.29 ± 0.52% when the addition amount of LF was 2 mg. The simulated gastric digestion results demonstrated that CMCS self-coacervates could protect more than 80% of LF from hydrolysis and maintain the bioactivities of LF. Accordingly, the self-coacervation of CMCS could be used as a pH-responsive encapsulation and delivery strategy.

Encapsulation of phenolic compounds within food-grade carriers and delivery systems by pH-driven method: a systematic review

In comparison to conventional encapsulation methods of phenolic compounds (PCs), pH-driven method is green, simple and requires low energy consumption. It has a huge potential for industrial applications, and can overcome more effectively the aqueous solubility, stability and bioavailability issues related to PCs by changing pH to induce the encapsulation of PCs. This review aims to shed light on the use of pH-driven method for encapsulating PCs. The preparation steps and principles governing pH-driven method using various carriers and delivery systems are provided. A comparison of pH-driven with other methods is also presented. To circumvent the drawbacks of pH-driven method, improvement strategies are proposed. The essence of pH-driven method relies simultaneously on alkalization and acidification to bind PCs and carriers. It is used for the development of nanoemulsions, liposomes, edible films, nanoparticles, nanogels and functional foods. As a result of pH-driven method, PCs-loaded carriers may have smaller size, high encapsulation efficiency, more sustained-release and good bioavailability, due mainly to effects of pH change on the structure and properties of PCs as well as carriers. Finally, modification of wall materials and type of acidifier are considered as efficient approaches to improve the pH-driven method.