Encapsulation, protection, and release of hydrophilic active components: potential and limitations of colloidal delivery systems

Nanoencapsulation of Thyme Essential Oils: Formulation, Characterization, Storage Stability, and Biological Activity

This study aimed to improve the effectiveness of Thymus capitatus and Thymus algeriensis essential oils (EOs), as food preservatives, through their encapsulation in different delivery systems (DSs), namely nanoemulsions and biopolymeric nanoparticles. DSs’ preparation is tailored to enhance not only physical stability but also resulting Eos’ antioxidant and antibacterial activities through different fabrication methods (high-pressure homogenization emulsification or antisolvent precipitation) and using different emulsifiers and stabilizers. DSs are characterized in terms of droplet size distribution, ζ-potential, and stability over time, as well as antioxidant and antibacterial activities of encapsulated EOs. The antioxidant activity was studied by the FRAP assay; the antibacterial activity was evaluated by the well diffusion method. EOs of different compositions were tested, namely two EOs extracted from Thymus capitatus, harvested from Tunisia during different periods of the year (TC1 and TC2), and one EO extracted from Thymus algeriensis (TA). The composition of TC1 was significantly richer in carvacrol than TC2 and TA. The most stable formulation was the zein-based nanoparticles prepared with TC1 and stabilized with maltodextrins, which exhibit droplet size, polydispersity index, ζ-potential, and encapsulation efficiency of 74.7 nm, 0.14, 38.7 mV, and 99.66%, respectively. This formulation led also to an improvement in the resulting antioxidant (60.69 µg/mg vs. 57.67 µg/mg for non-encapsulated TC1) and antibacterial (inhibition diameters varying between 12 and 33 mm vs. a range between 12 and 28 mm for non-encapsulated TC1) activities of EO. This formulation offers a promising option for the effective use of natural antibacterial bioactive molecules in the food industry against pathogenic and spoilage bacteria.

Advances in Protein-Based Nanocarriers of Bioactive Compounds: From Microscopic Molecular Principles to Macroscopical Structural and Functional Attributes

Many proteins can be used to fabricate nanocarriers for encapsulation, protection, and controlled release of nutraceuticals. This review examined the protein-based nanocarriers from microscopic molecular characteristics to the macroscopical structural and functional attributes. Structural, physical, and chemical properties of protein-based nanocarriers were introduced in detail. The spatial size, shape, water dispersibility, colloidal stability, etc. of protein-based nanocarriers were largely determined by the molecular physicochemical principles of protein. Different preparative techniques, including antisolvent precipitation, pH-driven, electrospray, and gelation methods, among others, can be used to fabricate different protein-based nanocarriers. Various modifications based on physical, chemical, and enzymatic approaches can be used to improve the functional performance of these nanocarriers. Protein is a natural resource with a wide range of sources, including plant, animal, and microbial, which are usually used to fabricate the nanocarriers. Protein-based nanocarriers have many advantages in aid of the application of bioactive ingredients to the medical, food, and cosmetic industries.

Formation and stabilization of multiple w/o/w emulsions encapsulating catechin, by mechanical and microfluidic methods using a single pH-sensitive copolymer: effect of copolymer/drug interaction

Multiple w/o/w emulsions (MEs) are promising systems for protecting fragile hydrophilic drugs and controlling their release. We explore the capacity of a single pH-sensitive copolymer, PDMS₆₀-b-PDMAEMA₅₀, and salts, to form and stabilize MEs loaded with sucrose or catechin by a one-step mechanical process or a microfluidic method. ME cytotoxicity was evaluated in various conditions of pH. Using the mechanical process, the most stable emulsions were obtained with Miglyol®812N and isopropyl myristate in a final pH range of 8-12 and [0.3 M-1 M] NaCl concentrations. Conversely, with the microfluidic method, isopropyl myristate at pH 3 without salt was more efficient. Catechin strongly affected the formation of droplets by the mechanical process but did not modify the conditions of stability of MEs obtained by the microfluidic method. The antioxidant power of catechin was preserved in the inner droplets, even in emulsions prepared by the mechanical method at pH 8. An incomplete release of sucrose and catechin from the emulsions was observed and attributed to the interaction of molecules with the copolymer through hydrogen bonding. This study highlights some of the barriers to break to formulate multiple emulsions stabilized by a PDMS-b-PDMAEMA copolymer or other polymers which can form hydrogen bonds interaction with encapsulated drugs.

Engineering Emulsion Gels as Functional Colloids Emphasizing Food Applications: A Review

Gels are functional materials with well-defined structures (three-dimensional networks) assembled from the dispersed colloids, and capable of containing a large amount of water, oil, or air (by replacing the liquid within the gel pores), known as a hydrogel, oleogel, and aerogel, respectively. An emulsion gel is a gelled matrix filled with emulsion dispersion in which at least one phase, either continuous phase or dispersed phase forms spatial networks leading to the formation of a semisolid texture. Recently, the interest in the application of gels as functional colloids has attracted great attention in the food industry due to their tunable morphology and microstructure, promising physicochemical, mechanical, and functional properties, and superior stability, as well as controlled release, features for the encapsulated bioactive compounds. This article covers recent research progress on functional colloids (emulsion gels), including their fabrication, classification (protein-, polysaccharide-, and mixed emulsion gels), and properties specifically those related to the gel-body interactions (texture perception, digestion, and absorption), and industrial applications. The emerging applications, including encapsulation and controlled release, texture design and modification, fat replacement, and probiotics delivery are summarized. A summary of future perspectives to promote emulsion gels' use as functional colloids and delivery systems for scouting potential new applications in the food industry is also proposed. Emulsion gels are promising colloids being used to tailor breakdown behavior and sensory perception of food, as well as for the processing, transportation, and targeted release of food additives, functional ingredients, and bioactive substances with flexibility in designing structural and functional parameters.

Microencapsulation of Natural Food Antimicrobials: Methods and Applications

The global demand for safe and healthy food with minimal synthetic preservatives is continuously increasing. Some natural food antimicrobials with strong antimicrobial activity and low toxicity have been considered as alternatives for current commercial food preservatives. Nonetheless, these natural food antimicrobials are hardly applied directly to food products due to issues such as food flavor or bioavailability. Recent advances in microencapsulation technology have the potential to provide stable systems for these natural antibacterials, which can then be used directly in food matrices. In this review, we focus on the application of encapsulated natural antimicrobial agents, such as essential oils, plant extracts, bacteriocins, etc., as potential food preservatives to extend the shelf-life of food products. The advantages and drawbacks of the mainly used encapsulation methods, such as molecular inclusion, spray drying, coacervation, emulsification, supercritical antisolvent precipitation and liposome and alginate microbeads, are discussed. Meanwhile, the main current applications of encapsulated antimicrobials in various food products, such as meat, dairy and cereal products for controlling microbial growth, are presented.

Nanoencapsulated Extract of a Red Seaweed (Rhodophyta) Species as a Promising Source of Natural Antioxidants

Marine seaweed species represent an important source of bioactive compounds possessing antioxidant activity. This study aimed at evaluating the antioxidant capacity of the Jania rubens algal extract by means of two antioxidant assays, i.e., 2,2-diphenyl-1-picrylhydrazyl and ferric-reducing antioxidant power. The seaweeds' total phenolic and flavonoid contents were also assayed as markers of antioxidant activity. To identify active agents responsible for the antioxidant activity, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry were used for comprehensive metabolites characterization. To enhance the Jania rubens efficacy, the extract was nanoencapsulated using an ionic gelation method by means of high-pressure homogenization. The optimum nanoformulation had a particle size of 161 nm, a ζ potential of 31.2 mV, a polydispersity index of 0.211, and entrapment efficiency of 99.7%. The in vitro phytochemicals' release profiles of Jania rubens chitosan nanoparticles in comparison to the concentration of the raw algal extract were studied by the dialysis bag diffusion method revealing that the extract was released in a controlled pattern. The results indicated the potential advantages of the encapsulated Jania rubens extract, with its potent antioxidant activity, for use in different applications where sustained release is useful.

Cubosomes and Hexosomes as Novel Nanocarriers for Bioactive Compounds

Cubosomes and hexosomes are nanostructured liquid crystalline particles, known as biocompatible nanocarriers for drug delivery. In recent years, there has been good interest in using cubosomes and hexosomes for the delivery of bioactive compounds in functional foods. These systems feature thermodynamic stability, encapsulate both hydrophobic and hydrophilic substances, and have a high tolerance to environmental stresses and potential for controlled release. This review outlines the recent advances in cubosomes and hexosomes in the food industry, focusing on their structure, composition, formation mechanisms, and factors influencing phase transformation between cubosomes and hexosomes. The potential applications especially for the bioactive delivery are presented. The integration of cubosomes and hexosomes with other emerging encapsulation technologies such as surface coating, gelation, and incorporation of polymers are also discussed.

Recent progress in oil-in-water-in-oil (O/W/O) double emulsions

Oil-in-water-in-oil (O/W/O) double emulsions are recognized as an advanced design route for oil structuring that shows promising applications in the pharmaceutical, cosmetic, and food fields. This review summarizes the main research advances of O/W/O double emulsions over the past two decades. It mainly focuses on understanding the preparation strategies, stabilization mechanism, and potential applications of O/W/O double emulsions. Several emulsification strategies are discussed, including traditional two-step emulsification method, phase-inversion approach, membrane emulsification, and microfluidic emulsification. Further, the role of interfacial stabilizers and viscosity in the stability of O/W/O double emulsions will be discussed with a focus on synthetic emulsifiers, natural biopolymer sand solid particles for achieving this purpose. Additionally, analytical methods for evaluating the stability of O/W/O double emulsions, such as advanced microscopy, rheology, and labeling assay are reviewed taking into account potential limitations of these characterization techniques. Moreover, possible innovative food applications are highlighted, such as simulating fat substitutes to decrease the trans- or saturated fatty acid content and developing novel delivery and encapsulation systems. This review paves a solid way for the exploration of O/W/O double emulsions toward large-scale implementation within the food industry.

Preparation of Water-in-Oil Nanoemulsions Loaded with Phenolic-Rich Olive Cake Extract Using Response Surface Methodology Approach

In this study, we aimed to prepare stable water-in-oil (W/O) nanoemulsions loaded with a phenolic-rich aqueous phase from olive cake extract by applying the response surface methodology and using two methods: rotor-stator mixing and ultrasonic homogenization. The optimal nanoemulsion formulation was 7.4% (w/w) of olive cake extract as the dispersed phase, and 11.2% (w/w) of a surfactant mixture of polyglycerol polyricinoleate (97%) and Tween 80 (3%) in Miglyol oil as the continuous phase. Optimum results were obtained by ultrasonication for 15 min at 20% amplitude, yielding W/O nanoemulsion droplets of 104.9 ± 6.7 nm in diameter and with a polydispersity index (PDI) of 0.156 ± 0.085. Furthermore, an optimal nanoemulsion with a droplet size of 105.8 ± 10.3 nm and a PDI of 0.255 ± 0.045 was prepared using a rotor-stator mixer for 10.1 min at 20,000 rpm. High levels of retention of antioxidant activity (90.2%) and phenolics (83.1-87.2%) were reached after 30 days of storage at room temperature. Both W/O nanoemulsions showed good physical stability during this storage period.

Novel glass capillary microfluidic devices for the flexible and simple production of multi-cored double emulsions

HYPOTHESIS

Double emulsions with many monodispersed internal droplets are required for the fabrication of multicompartment microcapsules and tissue-like synthetic materials. These double emulsions can also help to optically resolve different coalescence mechanisms contributing to double emulsion destabilization. Up to date microfluidic double emulsions are limited to either core-shell droplets or droplets with eight or less inner droplets. By applying a two-step jet break-up within one setup, double emulsion droplets filled with up to several hundred monodispersed inner droplets can be achieved.

EXPERIMENTS

Modular interconnected CNC-milled Lego®-inspired blocks were used to create two separated droplet break-up points within coaxial glass capillaries. Inner droplets were formed by countercurrent flow focusing within a small inner capillary, while outer droplets were formed by co-flow in an outer capillary. The size of inner and outer droplets was independently controlled since the two droplet break-up processes were decoupled.

FINDINGS

With the developed setup W/O/W and O/W/O double emulsions were produced with different surfactants, oils, and viscosity modifiers to encapsulate 25-400 inner droplets in each outer drop with a volume percentage of inner phase between 7% and 50%. From these emulsions monodispersed multicompartment microcapsules were obtained. The report offers insights on the relationship between the coalescence of internal droplets and their release.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

Preparation of ultra-long stable ovalbumin/sodium carboxymethylcellulose nanoparticle and loading properties of curcumin

OVA (ovalbumin)/CMC (sodium carboxymethylcellulose) nanoparticles are prepared by combining complex coacervation and thermal induction. The effect of different parameters on stability of OVA/CMC nanoparticles (different ratios, pH, temperature, salt concentration and storage time) is investigated. And then the loading and stabilizing mechanism of particles on curcumin are further analyzed. After heating, OVA and CMC in particle could further cross-linking and a highly salt-tolerant and ultra-long stable nanoparticle can be formed. OVA/CMC nanoparticle with the loose structure of wool ball could effectively load curcumin with the loading content and loading efficiency of 36.40 and 95.40%, 36.30 and 92.82%, 36.0 and 94.48% for the ratios of 1:2, 1:1 and 2:1, respectively. Curcumin-loaded of OVA/CMC nanoparticles show good DPPH· scavenging activity, Ferric-reducing ability and ABTS⁺ scavenging activity compared with curcumin/water. The results can be useful for designing food and beverage particle with improving bioactive substances functional properties.

Co-encapsulation of (-)-epigallocatechin-3-gallate and quercetin in double emulsion hydrogel beads: Microstructures, functional properties, and digestion behaviors

Co-loaded (-)-epigallocatechin-3-gallate (EGCG) and quercetin double emulsions and hydrogel beads were prepared, and their structure, functions, and digestion characteristics were investigated. The double emulsion particles were adsorbed by the cross-linked chains of the hydrogel beads. The encapsulation efficiencies of EGCG and quercetin within the hydrogel beads were higher than those within the double emulsion, while the antioxidant activities of the double emulsions were higher than those of the hydrogel beads. A lower amount of free fatty acids (FFAs) was released from the hydrogel beads than that released from the double emulsions. The bioavailability of EGCG was higher in the hydrogel beads than those in the double emulsions, while the quercetin bioavailability was not significantly different expect for the ratio of 3:7. The hydrogel beads remained intact in the stomach; however, numerous oil spills occurred in the small intestine. These data may improve double-emulsion-based delivery systems for controlled lipolysis and the release of co-encapsulated hydrophilic and lipophilic bioactive compounds.

Phenolic compounds as antidiabetic, anti-inflammatory, and anticancer agents and improvement of their bioavailability by liposomes

Phenolic compounds, widespread in plants, are a necessary part of the human regimen due to their antioxidant and pro-oxidative properties. Naturally, phenolics structurally range from a very simple phenolic molecule moiety to an intricate polymer. For decades, phenolic compounds have gained pronounced attention because of their protective effects against degenerative disorders such as inflammation, diabetes and cancer. Physico-chemical properties (eg, solubility) restricted their bioactivity and also limited their usage as nutraceutical ingredients. However, encapsulation technology like liposomal formulations has been developed for the delivery of phenolic compounds without affecting their original aesthetic and organoleptic property. Hence, this review outlines the antioxidant and pro-oxidative properties of phenolic compounds and focuses on biological activity reports of flavonoids and phenolic acids as antidiabetic, anti-inflammatory and anticancer agents. Also, the delivery applications of phenolic compounds as liposomes are discussed with few examples.

Effects of a Nanoencapsulated Moringa Leaf Ethanolic Extract on the Physiology, Metabolism and Reproductive Performance of Rabbit Does during Summer

This study investigated the effect of Moringa leaf ethanolic extract (MLEE) on heat-tolerance variables and the reproductive performance of rabbit does bred under hot climate conditions. Additionally, the effect of nanoencapsulation technology on the biological efficiency of MLEE was considered. A total of 56 rabbit does were randomly divided into four experimental groups and treated with 50 mg/kg body weight (BW) nonencapsulated MLEE, 25 or 10 mg/kg BW nanoencapsulated MLEE, or not treated (Control, C). The treatments continued for 50 days, including mating and pregnancy times. Physiological and hematochemical variables, hormonal profiles, and reproductive performance (kindling rate and litter characteristics) were determined. The active components of MLEE were identified. The results indicated that MLEE has 30 active components. All MLEE-based treatments reduced heat-stress-related indicators, such as rectal temperatures, respiratory rates and heart rate; improved hematochemical attributes, redox status, and hormones (progesterone and prolactin); and increased the total litter size, the kindling rate, litter size at birth and litter weight at birth. Adding MLEE can alleviate the negative impacts of heat stress by improving metabolism, redox status, and hormonal balance during pregnancy. These effects were seen whether MLLE was in free or encapsulated forms. However, the use of nanoencapsulated MLEE allowed 80% reduction (10 mg/kg BW) in the optimal dose (50 mg/kg BW) without affecting the efficiency of the treatment. These results support the importance of nanoencapsulation technology in improving the bioavailability of active components when they are orally administered.

Influence of Sodium Alginate Concentration on Microcapsules Properties Foreseeing the Protection and Controlled Release of Bioactive Substances

To understand the abilities of Ca-alginate microcapsules and their specific applications in different fields, it is necessary to determine the physicochemical and structural properties of those formulated microcapsules. In this work, we aimed to study the effect of alginate concentration in the improvement of the encapsulation efficiency (EE) and on the release of phenolic and flavonoid substances. The relationship between the structure of the encapsulated bioactive substance and Ca-alginate network and their effect on the EE and release kinetics have been investigated. The incorporation, structure, morphology, and phase properties of all elaborated materials were characterized by UV-spectroscopy, Fourier transform infrared (ATR-FTIR), scanning electron microscope (SEM), and X-ray diffraction (DRX). The results indicate that increasing the polymer concentration increases the EE and decreases the loading capacity (LC), whereas the effect of alginate polymer concentration on the release was not observed. The release study of bioactive substances showed that the release kinetics is relatively dependent on the structure and the physicochemical characteristics of the bioactive substance, which became clear when the encapsulated compounds were released from the core of calcium alginate microcapsules. Thus, it could be concluded that the pores size of the Ca-alginate network is smaller than the volume of the crocin molecule (2794.926 Å3) and higher than the volume of the gallic acid molecule (527.659 Å3). For the same microcapsules system, the release mechanism is affected by the structure and physicochemical properties of the encapsulated molecules.

Towards the systematic design of multilayer O/W emulsions with tannic acid as an interfacial antioxidant

This work discusses the possibility of designing multilayer oil-in-water emulsions to introduce the maximum possible amount of an antioxidant at the droplet interfaces for the optimal protection of a linseed oil core against oxidation, using a systematic three-step colloidal procedure. An antioxidant (here Tannic Acid - TA) is chosen and its interactions with a primary emulsifier (here Bovine Serum Albumin - BSA) and several polysaccharides are first examined in solution using turbidity measurements. As a second step, LbL deposition on solid surfaces is used to determine which of the polysaccharides to combine with BSA and tannic acid in a multilayer system to ensure maximum presence of tannic acid in the films. From UV-vis and polarization modulation infrared reflection-absorption (PM-IRRAS) spectroscopic measurements it is suggested that the best components to use in a multilayer emulsion droplet, together with BSA and TA, are chitosan and pectin. BSA, chitosan and pectin are subsequently used for the formation of three-layer linseed oil emulsions, and tannic acid is introduced into any of the three layers as an antioxidant. The effect of the exact placement of tannic acid on the oxidative stabilization of linseed oil is assessed by monitoring the fluorescence of Nile red, dissolved in the oil droplets, under the attack of radicals generated in the aqueous phase of the emulsion. From the results it appears that the three-stage procedure presented here can serve to identify successful combinations of interfacial components of multilayer emulsions. It is also concluded that the exact interfacial placement of the antioxidant plays an important role in the oxidative stabilization of the valuable oil core.

Combination of copigmentation and encapsulation strategies for the synergistic stabilization of anthocyanins

Copigmentation and encapsulation are the two most commonly used techniques for anthocyanin stabilization. However, each of these techniques by itself suffers from many challenges associated with the simultaneous achievement of color intensification and high stability of anthocyanins. Integrating copigmentation and encapsulation may overcome the limitation of usage of a single technique. This review summarizes the most recent studies and their challenges aiming at combining copigmentation and encapsulation techniques. The effective approaches for encapsulating copigmented anthocyanins are described, including spray/freeze-drying, emulsification, gelation, polyelectrolyte complexation, and their combinations. Other emerging approaches, such as layer-by-layer deposition and ultrasonication, are also reviewed. The physicochemical principles underlying the combined strategies for the fabrication of various delivery systems are discussed. Particular emphasis is directed toward the synergistic effects of copigmentation and encapsulation, for example, modulating roles of copigments in the processes of gelation and complexation. Finally, some of the major challenges and opportunities for future studies are highlighted. The trend of integrating copigmentation and encapsulation has been just started to develop. The information in this review should facilitate the exploration of the combination of multistrategy and the fabrication of robust delivery systems for copigmented anthocyanins.

Chlorogenic acid sustained-release gel for treatment of glioma and hepatocellular carcinoma

Chlorogenic acid (CGA) may provide an effective and safe option for tumor treatment. However, its application is limited because of short residence time in vivo and repeated administration required. A phospholipid-based in situ gel containing chlorogenic acid (CGA PG) was prepared via a simple way. The CGA PG exhibited good fluidity, easy injectability, high-drug-loading capacity, and suitable sustained-release behavior whether in vitro or in vivo. Furthermore, CGA PG could suppress tumor growth with no significant side effects. Overall, CGA PG may be a promising sustained drug delivery system with excellent therapeutic effect on glioma and hepatocellular carcinoma.

Partition and stability of folic acid and caffeic acid in hollow zein particles coated with chitosan

The carriers for hydrophobic bioactives have been extensively studied, while those for hydrophilic bioactives are still challenging. The partition of bioactives in the particles depends greatly on their solubility, interaction with carrier materials, as well as structure of carriers. In this study, chitosan-coated hollow zein particles using calcium phosphate as a sacrificing template (CS-HZ) were fabricated to co-encapsulate folic acid (FA) and caffeic acid (CA). Partition, photostability, and antioxidant capacity of bioactive compounds were also studied. The size, polydispersity index and ζ-potential of optimized CS-HZ were 176.3 nm, 0.14 and +39.3 mV, respectively, indicating their small and uniform dimension with excellent colloidal stability. FA interacted with chitosan to form complexes and then coated on the zein particles where CA was encapsulated. After co-encapsulation in CS-HZ, the photostability of both FA and CA was improved in comparison with encapsulation of single compound, with 85% of FA remaining after 240 min of UVA irradiation, and 90% of CA remaining after 80 min. Antioxidant activity of CA decreased upon encapsulation, but significantly increased after irradiation. Findings in this study shed some light on the design of carriers for co-delivery of hydrophilic compounds in acidic condition.

Preparation and evaluation of lecithin/zein hybrid nanoparticles for the oral delivery of Panax notoginseng saponins

Panax Notoginseng Saponins (PNS) has been widely used in the prevention and treatment of cardiovascular and cerebrovascular diseases such as myocardial infarction, heart failure and cerebral infarction. However, oral administration of PNS showed low bioavailability because of its instability and poor membrane permeability in the gastrointestinal tract. Here, lipoprotein-inspired hybrid nanoparticles of PNS-Lecithin-Zein (PLZ-NPs) were prepared by using a simple phase separation method, which possessed a core-shell structure, where zein was used as protein part to replace the animal origin protein to increase the resistance to acid and enzymes while lecithin was used as the lipid composition to improve the oral absorption of PNS as well as to increase the drug loading capacity of PNS into the nanocarriers. The results of stability test showed that PLZ-NPs had robust enzymolysis resistance ability for acid and digestive enzymes of gastrointestinal environments. The fluorescent resonance energy transfer (FRET) assay confirmed the ability of LZ-NPs to be intactly absorbed by Caco-2 cell monolayer. Cell transport studies demonstrated that the permeability of PLZ-NPs in Caco-2/HT29-MTX co-culture cell model was 1.5-fold that of PNS. Meanwhile, the single-pass intestinal perfusion assay proved the absorption parameter Peff of PLZ-NPs was 1.75 and 1.80 times higher than that of PNS in the ileum and jejunum, respectively. Finally, the in vivo pharmacokinetic experiment showed that the relative oral bioavailability of PLZ-NPs was 1.71-fold that of free PNS in SD rat. In summary, the employment of the Lecithin/Zein hybrid nanoparticles could be considered as a promising approach for PNS analogues.

Combining edible coatings technology and nanoencapsulation for food application: A brief review with an emphasis on nanoliposomes

The use of bioactive compounds within the biopolymer-based Edible Coatings (EC) matrices has certain limitations for their application at the food industry level. Encapsulation has been considered as a strategy that enables protecting and improving the physical and chemical characteristics of the compounds; as a result, it extends the shelf life of coated foods. This review discusses recent progress in combining edible coatings with nanoencapsulation technology. We also described and discussed various works, in which nanoliposomes are used as encapsulation systems to prepare, and subsequently apply the edible coatings in plant products and meat products. The use of nanoliposomes for the encapsulation of phenolic compounds and essential oils provides an improvement in the antioxidant and antimicrobial properties of coatings by extending the shelf life of food matrices. However, when liposomes are stored for a long period of time, they may present some degree of instability manifested by an increase in size, polydispersity index, and zeta potential. This is reflected in an aggregation, fusion, and rupture of the vesicles. This investigation can help researchers and industries to select an appropriate and efficient biopolymer to form EC containing nanoencapsulated active compounds. This work also addresses the use of nanoliposomes to create EC extending markedly the shelf life of fruit, reducing the weight loss, and deterioration due to the action of microorganisms.

Formulation and characterization of zein/gum arabic nanoparticles for the encapsulation of a rutin-rich extract from Ruta chalepensis L

Rutin, a plant flavonol characterized by a wide range of biological effects, has limited application in foods because of its low water solubility and scarce bioavailability. This work aimed to investigate the encapsulation of a rutin-rich extract (200.6 ± 1.5 mg/g of rutin) from Ruta chalepensis L. in zein nanoparticles (hydrodynamic diameter of 80-170 nm) prepared by antisolvent precipitation and stabilized by gum arabic (GA). The addition of GA (1:1 mass ratio with zein) significantly reduced the instability phenomena of zein nanoparticles through the deposition of a negatively charged layer as evidenced by the zeta potential and the UV-visible measurement, suggesting an electrostatic interaction between zein and GA. It also contributed to enhancing the encapsulation efficiency of rutin and inducing a rapid release during simulated digestion. These findings show that zein/GA nanoparticles represent a promising delivery system for natural extracts, fabricated through a facile and versatile process.

Influence of Hydrophilic Surfactants on the W1–W2 Coalescence in Double Emulsion Systems Investigated by Single Droplet Experiments

Double emulsions are a promising formulation for encapsulation and targeted release in pharmaceutics, cosmetics and food. An inner water phase is dispersed in an oil phase, which is again emulsified in a second water phase. The encapsulated inner water phase can be released via diffusion or via coalescence, neither of which is desired during storage but might be intended during application. The two interfaces in a double emulsion are stabilized by a hydrophilic and a lipophilic surfactant, to prevent the coalescence of the outer and the inner emulsion, respectively. This study focuses on the influence of the hydrophilic surfactant on the release of inner water or actives encapsulated therein via coalescence of the inner water droplet with the outer O–W2 interface. Since coalescence and diffusion are difficult to distinguish in double emulsions, single-droplet experiments were used to quantify differences in the stability of inner droplets. Different lipophilic (PGPH and PEG-30 dipolyhydroxylstearate) and hydrophilic surfactants (ethoxylates, SDS and polymeric) were used and resulted in huge differences in stability. A drastic decrease in stability was found for some combinations, while other combinations resulted in inner droplets that could withstand coalescence longer. The destabilization effect of some hydrophilic surfactants depended on their concentration, but was still present at very low concentrations. A huge spread of the coalescence time for multiple determinations was observed for all formulations and the necessary statistical analysis is discussed in this work. The measured stabilities of single droplets are in good accordance with the stability of double emulsions for similar surfactant combinations found in literature. Therefore, single droplet experiments are suggested for a fast evaluation of potentially suitable surfactant combinations for future studies on double-emulsion stability.

Influence of food matrix and food processing on the chemical interaction and bioaccessibility of dietary phytochemicals: A review

Consumption of phytochemicals-rich foods shows the health effect on some chronic diseases. However, the bioaccessibility of these phytochemicals is extremely low, and they are often consumed in the diet along with the food matrix. The food matrix can be described as a complex assembly of various physical and chemical interactions that take place between the compounds present in the food. Some studies indicated that the physiological response and the health benefits of phytochemicals are resultant in these interactions. Some food substrates inhibit the absorption of phytochemicals via this interaction. Moreover, processing technologies have been developed to facilitate the release and/or to increase the accessibility of phytochemicals in plants or breakdown of the food matrix. Food processing processes may disrupt the activity of phytochemicals or reduce bioaccessibility. Enhancement of functional and sensorial attributes of phytochemicals in the daily diet may be achieved by modifying the food matrix and food processing in appropriate ways. Therefore, this review concisely elaborated on the mechanism and the influence of food matrix in different parts of the digestive tract in the human body, the chemical interaction between phytochemicals and other compounds in a food matrix, and the various food processing technologies on the bioaccessibility and chemical interaction of dietary phytochemicals. Moreover, the enhancing of phytochemical bioaccessibility through food matrix design and the positive/negative of food processing for dietary phytochemicals was also discussed in this study.

Development of nanoparticle-delivery systems for antiviral agents: A review

The COVID-19 pandemic has resulted in unprecedented increases in sickness, death, economic disruption, and social disturbances globally. However, the virus (SARS-CoV-2) that caused this pandemic is only one of many viruses threatening public health. Consequently, it is important to have effective means of preventing viral transmission and reducing its devastating effects on human and animal health. Although many antivirals are already available, their efficacy is often limited because of factors such as poor solubility, low permeability, poor bioavailability, un-targeted release, adverse side effects, and antiviral resistance. Many of these problems can be overcome using advanced antiviral delivery systems constructed using nanotechnology principles. These delivery systems consist of antivirals loaded into nanoparticles, which may be fabricated from either synthetic or natural materials. Nevertheless, there is increasing emphasis on the development of antiviral delivery systems from natural substances, such as lipids, phospholipids, surfactants, proteins, and polysaccharides, due to health and environmental issues. The composition, morphology, dimensions, and interfacial characteristics of nanoparticles can be manipulated to improve the handling, stability, and potency of antivirals. This article outlines the major classes of antivirals, summarizes the challenges currently limiting their efficacy, and highlights how nanoparticles can be used to overcome these challenges. Recent studies on the application of antiviral nanoparticle-based delivery systems are reviewed and future directions are described.

Biopolymer-liposome hybrid systems for controlled delivery of bioactive compounds: Recent advances

Conventional liposomes still face many challenges associated with the poor physical and chemical stability, considerable loss of encapsulated cargo, lack of stimulus responsiveness, and rapid elimination from blood circulation. Integration of versatile functional biopolymers has emerged as an attractive strategy to overcome the limitation of usage of liposomes. This review comprehensively summarizes the most recent studies (2015-2020) and their challenges aiming at the exploration of biopolymer-liposome hybrid systems, including surface-modified liposomes, biopolymer-incorporated liposomes, guest-in-cyclodextrin-in-liposome, liposome-in-hydrogel, liposome-in-film, and liposome-in-nanofiber. The physicochemical principles and key technical information underlying the combined strategies for the fabrication of polymeric liposomes, the advantages and limitations of each of the systems, and the stabilization mechanisms are discussed through various case studies. Special emphasis is directed toward the synergistic efficiencies of biopolymers and phospholipid bilayers on encapsulation, protection, and controlled delivery of bioactives (e.g., vitamins, carotenoids, phenolics, peptides, and other health-related compounds) for the biomedical, pharmaceutical, cosmetic, and functional food applications. The major challenges, opportunities, and possible further developments for future studies are also highlighted.

Tea polyphenols encapsulated in W/O/W emulsions with xanthan gum-locust bean gum mixture: Evaluation of their stability and protection

Herein, improvement of the stability of the water-in-oil-in-water (W/O/W) emulsions by addition of xanthan gum (XG)/locust bean gum (LBG) mixture in the inner water phase was aimed. The impact of XG/LBG mixture on the physical stability, microstructure and rheological properties of W/O/W emulsions was investigated. It was found that, compared with the control emulsions, the presence of XG/LBG mixture could improve the stability of W/O/W emulsions against coalescence. The tea polyphenols (TPPs) and XG/LBG mixture were simultaneously included in the internal aqueous phase of the double emulsion and stored at 25 and 40 °C in the dark for 28 d. The results showed that XG/LBG mixture not only had a protective role for TPPs encapsulated in the internal water phase, but also maintained more than 50% of the antioxidant capacity of TPPs.