Encapsulation of omega-3 fatty acids in nanoemulsions and microgels: Impact of delivery system type and protein addition on gastrointestinal fate

Synthesis and characterization of ion-induced sodium alginate/soy protein isolate microgels for the controlled release

In this study, sodium alginate/ soy protein isolate (SPI) microgels cross-linked by various divalent cations including Cu2+, Ba2+, Ca2+, and Zn2+ were fabricated. Cryo-scanning electron microscopy observations revealed distinctive structural variations among the microgels. In the context of gastric pH conditions, the degree of shrinkage of the microgels followed the sequence of Ca2+ > Ba2+ > Cu2+ > Zn2+. Meanwhile, under intestinal pH conditions, the degree of swelling was ranked as Zn2+ > Ca2+ > Ba2+ > Cu2+. The impact of these variations was investigated through in vitro digestion studies, revealing that all microgels successfully delayed the release of β-carotene within the stomach. Within the simulated intestinal fluid, the microgel cross-linked with Zn2+ exhibited an initial burst release, while those cross-linked with Cu2+, Ba2+, or Ca2+ displayed a sustained release pattern. This research underscores the potential of sodium alginate/SPI microgels cross-linked with different divalent cations as efficient controlled-release delivery systems.

Prevention of Hypercholesterolemia with "Liposomes in Microspheres" Composite Carriers: A Promising Approach for Intestinal-Targeted Oral Delivery of Astaxanthin

Cardiovascular diseases are caused by hypercholesterolemia. Astaxanthin (AST) has been reported to exhibit antioxidant and anti-inflammatory properties. However, its bioavailability is poor because of low solubility and instability. In order to improve the bioavailability of AST, we developed an intestinal-responsive composite carrier termed as "liposomes in micropheres" incorporating N-succinyl-chitosan (NSC)-poly(ethylene glycol) (PEG) liposomes that functionalized by neonatal Fc receptors (FcRn) into hydrogels of sodium alginate (SA) and carboxymethyl chitosan (CMCS). In the AST NSC/HSA-PEG liposomes@SA/CMCS microspheres, the AST's encapsulation efficiency (EE) was 96.26% (w/w) and its loading capacity (LC) was 6.47% (w/w). AST NSC/HSA-PEG liposomes had stability in the gastric conditions and achieved long-term release of AST in intestinal conditions. Then, AST NSC/HSA-PEG liposomes@SA/CMCS bind to intestinal epithelial cell targets by the neonatal Fc receptor. In vitro permeation studies show that there was a 4-fold increase of AST NSC/HSA-PEG liposomes@SA/CMCS in AST permeation across the intestinal epithelium. Subsequent in vivo experiments demonstrated that the composite carrier exhibited a remarkable mucoadhesive capacity, allowing for extended intestinal retention of up to 12 h, and it displayed deep penetration through the mucus layer, efficiently entering the intestinal villi epithelial cells, and enhancing the absorption of AST and its bioavailability in vivo. And oral administration of AST NSC/HSA-PEG liposomes@SA/CMCS could effectively prevent hypercholesterolemia caused by a high-fat, high-cholesterol diet (HFHCD). These advancements highlight the potential of NSC/HSA-PEG liposomes@SA/CMCS composite carriers for targeted and oral uptake of hydrophobic bioactives.

Development and characterization of antimicrobial alginate hydrogel beads filled with cinnamon essential oil nanoemulsion

The aim of the present study was to investigate the characteristics of alginate beads filled with cinnamon essential oil nanoemulsions (CEONs). The influence of the alginate and CaCl2 concentrations on their physical, antimicrobial and antioxidant properties was studied. The droplet size of CEON was 146.20 ± 39.28 nm and the zeta potential was -33.8 ± 0.72 mV demonstrating proper nanoemulsions stability. Decreasing the alginate and CaCl2 concentrations resulted in higher EOs release due to the increased pore size of the alginate beads. The scavenging activity of DPPH of beads was found to be dependent on the alginate and calcium ion concentrations which affected the pore size of the fabricated beads. The FT-IR results declared the new bands in the spectra of filled hydrogel beads, which verified the encapsulation of EOs in the beads. The surface morphology of beads was studied using SEM images which showed the spherical shape and porous structure of alginate beads. In addition, the alginate beads filled with CEO nanoemulsion demonstrated strong antibacterial activity.

Development of engineered probiotics with tailored functional properties and their application in food science

The potential health benefits of probiotics may not be cognized because of the substantial curtailment in their viability during food storage and passage through the gastrointestinal system. Intestinal flora composition, and resistance against pathogens are among the health benefits associated with probiotic consumption. In the gastric environment, pH 2.0, probiotics dramatically lose their viability during the transit through the gastrointestinal system. The challenge remains to maintain cell viability until it reaches the large intestine. In extreme conditions, such as a decrease in pH or an increase in temperature, encapsulation technology can enhance the viability of probiotics. Probiotic bacterial strains can be encapsulated in a variety of ways. The methods are broadly systematized into two categories, liquid and solid delivery systems. This review emphasizes the technology used in the research and commercial sectors to encapsulate probiotic cells while keeping them alive and the food matrix used to deliver these cells to consumers.

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Effect of gelation technique on lipid digestibility of emulsion-loaded alginate microparticles: a systematic review and meta-analysis

Alginate microparticles fabricated via calcium gelation or layer-by-layer assembly are commonly used for encapsulating emulsions. In this study, the impact of these two gelation methods on the lipid digestibility of emulsions was reviewed through a systematic screening of relevant studies. From the literature search (Scopus, PubMed, and Web of Science databases), 604 records were screened and 25 articles were included in the analysis. The fold change of free fatty acid release rate at the end of in vitro digestion process between alginate-encapsulated emulsion and emulsions not encapsulated by alginate was calculated for calcium gelation (weighted mean of response ratio 0.64, 95% CI 0.54-0.75) and layer-by-layer assembly (weighted mean of response ratio 0.89, 95% CI 0.81-0.98). Alginate-calcium hydrogels showed stronger inhibition of the extent of lipid digestion than alginate-coated multilayer emulsions. The structural and particle size differences between alginate microparticles acquired using different techniques may contribute to this phenomenon.

Producing mixed-soy protein adsorption layers on alginate microgels to controlled-release β-carotene

In this study, the effects of soy protein isolate (SPI) on the morphology, encapsulation efficiency, storage stability, swelling behavior, and in vitro digestion behavior of calcium alginate (CA) microgels were investigated. CA and calcium alginate-SPI (CAS) microgels with encapsulated β-carotene were prepared by extruding a mixture of alginate and SPI using a co-extrusion technique, followed by cross-linking with Ca²⁺. All microgels exhibited homogeneous sizes and spherical shapes, and CAS microgels showed high levels of protein loading efficiency. The encapsulation efficiency and storage stability of β-carotene within CAS microgels were higher than those within CA microgels. The introduction of SPI into CAS microgels resulted in a higher degree of gel size shrinkage in gastric fluid and a lower degree of swelling in intestinal fluid compared to CA microgels. In vitro digestion was conducted to investigate the effects of the addition of SPI on the release behavior of CA and CAS microgels. Results obtained showed that CAS microgels were more resistant to simulated gastric fluid than CA microgels. Cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) observations indicated that the release behavior was dependent on the porosity of the CA and CAS microgels, and the porosity was influenced by the concentration of SPI. This study showed that the introduction of SPI to CA microgels can lead to the development of an effective controlled release delivery system.

Recent developments in industrial applications of nanoemulsions

Nanotechnology is being utilized in various industries to increase the quality, safety, shelf-life, and functional performance of commercial products. Nanoemulsions are thermodynamically unstable colloidal dispersions that consist of at least two immiscible liquids (typically oil and water), as well as various stabilizers (including emulsifiers, texture modifiers, ripening inhibitors, and weighting agents). They have unique properties that make them particularly suitable for some applications, including their small droplet size, high surface area, good physical stability, rapid digestibility, and high bioavailability. This article reviews recent developments in the formulation, fabrication, functional performance, and gastrointestinal fate of nanoemulsions suitable for use in the pharmaceutical, cosmetic, nutraceutical, and food industries, as well as providing an overview of regulatory and health concerns. Nanoemulsion-based delivery systems can enhance the water-dispersibility, stability, and bioavailability of hydrophobic bioactive compounds. Nevertheless, they must be carefully formulated to obtain the required functional attributes. In particular, the concentration, size, charge, and physical properties of the nano-droplets must be taken into consideration for each specific application. Before launching a nanoscale product onto the market, determination of physicochemical characteristics of nanoparticles and their potential health and environmental risks should be evaluated. In addition, legal, consumer, and economic factors must also be considered when creating these systems.

Hohenbuehelia serotina polysaccharides self-assembled nanoparticles for delivery of quercetin and their anti-proliferative activities during gastrointestinal digestion in vitro

In this study, the self-assembled nanoparticles based on Hohenbuehelia serotina polysaccharides (QC-HSP NPs) were fabricated to encapsulate quercetin for improving its bioavailability. The structural characteristics, physicochemical properties as well as the cytotoxicity activities of QC-HSP NPs during gastrointestinal digestion in vitro were respectively investigated. The results showed that QC-HSP NPs possessed the spherical and smooth surface morphology, with the average particle size of 360 nm and zeta potential of -38.8 mV. Moreover, QC-HSP NPs had excellent physiochemical stabilities, and presented sustained-release characteristics during gastrointestinal digestion in vitro. Compared with undigested ones, QC-HSP NPs after gastrointestinal digestion exhibited the more significant anti-proliferative activity on HeLa cells through accumulation of intracellular ROS, arrest of cell cycle at G2/M phase by regulation of cyclin B1, CDK1, p53 and p21 and induction of apoptosis by ER apoptosis pathway. This study provides a new strategy for designing quercetin-loaded nanoparticles based on natural polysaccharides to improve the bioavailability of quercetin.

Plant-Based Colloidal Delivery Systems for Bioactives

The supplementation of plant-based foods and beverages with bioactive agents may be an important strategy for increasing human healthiness. Numerous kinds of colloidal delivery systems have been developed to encapsulate bioactives with the goal of improving their water dispersibility, chemical stability, and bioavailability. In this review, we focus on colloidal delivery systems assembled entirely from plant-based ingredients, such as lipids, proteins, polysaccharides, phospholipids, and surfactants isolated from botanical sources. In particular, the utilization of these ingredients to create plant-based nanoemulsions, nanoliposomes, nanoparticles, and microgels is covered. The utilization of these delivery systems to encapsulate, protect, and release various kinds of bioactives is highlighted, including oil-soluble vitamins (like vitamin D), ω-3 oils, carotenoids (vitamin A precursors), curcuminoids, and polyphenols. The functionality of these delivery systems can be tailored to specific applications by careful selection of ingredients and processing operations, as this enables the composition, size, shape, internal structure, surface chemistry, and electrical characteristics of the colloidal particles to be controlled. The plant-based delivery systems discussed in this article may be useful for introducing active ingredients into the next generation of plant-based foods, meat, seafood, milk, and egg analogs. Nevertheless, there is still a need to systematically compare the functional performance of different delivery systems for specific applications to establish the most appropriate one. In addition, there is a need to test their efficacy at delivering bioavailable forms of bioactives using in vivo studies.

In vitro gastrointestinal digestion impact on stability, bioaccessibility and antioxidant activity of polyphenols from wild and commercial blackberries (Rubus spp.)

Gastrointestinal digestion (GID) is a physiological process that transforms the stability, bioaccessibility and antioxidant activity (AOX) of polyphenols from blackberries (Rubus spp.). This study aimed to investigate the effect of the INFOGEST® GID protocol on the phenolic stability, bioaccessibility and AOX of Mexican wild (WB) and commercial (CB) blackberries. After GID, the total phenolic and anthocyanin contents in blackberries decreased by ≥68% and ≥74%, respectively. More than 40 phenolics were identified during GID; most of them degraded completely during digestion. GID had a negative effect on the AOX of both fruits (>50%), but WB showed the highest antioxidant activities, as assessed by the ORAC, DPPH, reducing power and β-carotene bleaching methods. In Caco-2 cells, the cell-based antioxidant activity of digested blackberries (p < 0.05) decreased by 48% in WB and by 56% in CB. The capacity to inhibit intracellular ROS decreased by 50% in WB and by up to 86% in CB, after digestion. GID is a complex process that impacts on the bioactive properties of food nutrients, especially phenolics. In vitro and cellular AOX of WB polyphenols withstood the gastrointestinal environment better than CB phenolics. The in vitro assays results suggest that phenolics from underutilized WB have a higher bioaccessibility and antioxidant capacity than the polyphenols from the most frequently consumed CB. However, whether this corresponds to a better bioaccessibility in humans remains to be determined in future work.

Co-Encapsulated Synbiotics and Immobilized Probiotics in Human Health and Gut Microbiota Modulation

Growing interest in the development of innovative functional products as ideal carriers for synbiotics, e.g., nutrient bars, yogurt, chocolate, juice, ice cream, and cheese, to ensure the daily intake of probiotics and prebiotics, which are needed to maintain a healthy gut microbiota and overall well-being, is undeniable and inevitable. This review focuses on the modern approaches that are currently being developed to modulate the gut microbiota, with an emphasis on the health benefits mediated by co-encapsulated synbiotics and immobilized probiotics. The impact of processing, storage, and simulated gastrointestinal conditions on the viability and bioactivity of probiotics together with prebiotics such as omega-3 polyunsaturated fatty acids, phytochemicals, and dietary fibers using various delivery systems are considered. Despite the proven biological properties of synbiotics, research in this area needs to be focused on the proper selection of probiotic strains, their prebiotic counterparts, and delivery systems to avoid suppression of their synergistic or complementary effect on human health. Future directions should lead to the development of functional food products containing stable synbiotics tailored for different age groups or specifically designed to fulfill the needs of adjuvant therapy.

Proteolysis of whey protein isolates in nanoemulsion systems: Impact of nanoemulsification and additional synthetic emulsifiers

Nanoemulsions are currently of interest in the functional food sector because their small droplet size (100-500 nm) provides a number of potential advantages over conventional emulsions. This study concerned the behavior of nanoemulsions stabilized with whey proteins and two synthetic emulsifiers (Tween 80 and Croduret), and exposed to conditions simulating the human upper gastrointestinal tract. In particular, the effect of synthetic emulsifiers (food additives) on the interfacial composition and digestion rate of milk proteins at the interface of nanoemulsions was determined. The results indicate that the protein was partially co-absorbed with only one synthetic emulsifier (Croduret) at the interface, which made protein more resistant to digestion in the nanoemulsion system. This suggests that the degree of protein digestion can be controlled by appropriate selection of synthetic emulsifiers and presenting the protein in nanoemulsion system.

Effect of nanoemulsion particle size on the bioavailability and bioactivity of perilla oil in rats

The aim of this study was to investigate the bioavailability and bioactivity of perilla (Perilla frutescens) oil nanoemulsions prepared at different homogenization pressures by measuring the weight, fatty acid profile, and antioxidant and anti-inflammatory properties in rats. The high-pressure homogenization significantly reduced the particle size of perilla oil nanoemulsions and enhanced their stability, and the minimum particle size was 293.87 ± 6.55 nm at 120 MPa. There was an increase in the weight and fatty acid levels in the plasma and liver of test group rats. The highest glutathione (GSH) and the lowest malondialdehyde (MDA) levels of 18.76 ± 10.51 mg GSH/g prot and 20.27 ± 2.46 nmol/mg prot, respectively, were recorded in rats administrated perilla oil nanoemulsions prepared at 120 MPa. However, there was no significant difference in superoxide dismutase activity (SOD) between the groups. The interferon-gamma (IL-γ), interleukin-1 beta (IL-1β), IL-6 (interleukin-6), and IL-8 (interleukin-8) levels in the test groups were lower than those in the blank and control groups at 8 hr after lipopolysaccharide injection. The IL-1β, IL-6, and IL-8 levels were 49.52 ± 14.06, 90.13 ± 6.04, and 419.71 ± 32.03 ng/L, respectively, in rats treated with perilla oil nanoemulsions prepared at 120 MPa. Both perilla oil and its nanoemulsions decreased estradiol levels and damaged the ovaries. Overall, our findings show that the test nanoemulsions enhanced the bioavailability of perilla oil, which resulted in enhanced antioxidant and anti-inflammatory responses; thus, we provide a new approach to deliver perilla oil. PRACTICAL APPLICATION: Nanoemulsions can be used to deliver drugs and bioactive compounds, and perilla oil nanoemulsions can be used in healthcare products and beverage industries.

Enhancing the physicochemical stability and digestibility of DHA emulsions by encapsulation of DHA droplets in caseinate/alginate honeycomb-shaped microparticles

Docosahexaenoic acid (DHA) was encapsulated in caseinate/alginate microparticles by adjusting the pH based on the electrostatic complexation, in order to improve the physicochemical stability and digestibility of single caseinate-stabilized DHA emulsions. In this study, relatively stable honeycomb-shaped DHA microparticles were formed by electrostatic complexation between positively charged caseinate-coated DHA droplets, caseinate and negatively charged alginate at pH 4.5. The zeta-potential, particle size, size distribution, physical stability, microstructure, DHA oxidation and free fatty acids (FFA) release rate in a simulated gastrointestinal tract (GIT) model were determined. Dynamic light scattering (DLS) and confocal laser scanning microscopy (CLSM) measurements indicated that DHA microparticles had a particle size (1521.00 ± 39.15 nm) significantly larger than that of caseinate-stabilized DHA emulsions (243.23 ± 4.51 nm). The microparticles were much more stable near the isoelectric point (pI) of the adsorbed proteins compared with the single emulsions according to the original transmissions of LUMiSizer. The cryo-scanning electron microscopy (Cryo-SEM) images also showed that the microparticles formed a specific honeycomb-shaped network structure with more uniform distribution and without aggregation. The incorporation of DHA droplets into caseinate/alginate microparticles significantly ameliorated their chemical stability. GIT studies showed that the digestion of DHA microparticles was enhanced which was due to more open loose structures compared with the large-scale close-knit aggregation of DHA emulsion droplets. This study may provide useful information for the stabilization of functional food components and rational design of nutraceutical delivery systems.

Encapsulation Effect on the In Vitro Bioaccessibility of Sacha Inchi Oil (Plukenetia volubilis L.) by Soft Capsules Composed of Gelatin and Cactus Mucilage Biopolymers

Sacha inchi (Plukenetia volubilis L.) seed oil is a rich source of polyunsaturated fatty acids (PUFAs) that are beneficial for human health, whose nutritional efficacy is limited because of its low water solubility and labile bioaccessibility (compositional integrity). In this work, the encapsulation effect, using blended softgels of gelatin (G) and cactus mucilage (CM) biopolymers, on the PUFAs’ bioaccessibility of P. volubilis seed oil was evaluated during in vitro simulated digestive processes (mouth, gastric, and intestinal). Gas chromatography–mass spectrometry (GC–MS) and gas chromatography with a flame ionization detector (GC–FID) were used for determining the chemical composition of P. volubilis seed oil both before and after in vitro digestion. The most abundant compounds in the undigested samples were α-linolenic, linoleic, and oleic acids with 59.23, 33.46, and 0.57 (g/100 g), respectively. The bioaccessibility of α-linolenic, linoleic, and oleic acid was found to be 1.70%, 1.46%, and 35.8%, respectively, along with the presence of some oxidation products. G/CM soft capsules are capable of limiting the in vitro bioaccessibility of PUFAs because of the low mucilage ratio in their matrix, which influences the enzymatic hydrolysis of gelatin, thus increasing the release of the polyunsaturated content during the simulated digestion.

Modulation of physicochemical stability and bioaccessibility of β-carotene using alginate beads and emulsion stabilized by scallop (Patinopecten yessoensis) gonad protein isolates

The colloidal delivery systems fabricated by emulsion containing natural proteins and lipids have been utilized to protect carotenoids as well as to release the carotenoids in the simulated in vitro gastrointestinal tract (GIT). In this study, β-carotene (BC) was embedded into emulsions that were stabilized by scallop gonad protein isolates (SGPIs), and the emulsion droplets containing BC were then entrapped into calcium-alginate beads. The results showed that the oil-in-water emulsions coated by SGPIs only showed good stability at pH 7-8, while the emulsion-alginate beads remained relatively intact at pH 3-8. BC encapsulated in emulsions was extremely unstable and prone to degradation when stored at the comparatively higher temperature (37 °C), whereas the stability of BC was greatly enhanced through incorporation into emulsion-alginate beads. The digestion rate and extent of lipid droplets constructed within SGPIs-stabilized emulsion-alginate beads were slower than that in emulsions during GIT. The confocal laser scanning microscopy revealed that the lipid droplets in emulsions were aggregated after exposure to the mouth and gastric phases, while the emulsion-alginate beads maintained their spherical shape after exposure to the oral and gastric phases. Moreover, the free lipid droplets in the emulsions showed a higher bioaccessibility of BC (66%) than that in the emulsion-alginate beads (38%), whereas the BC transformation was on the contrary. The findings in this study indicated that SGPIs-stabilized emulsion in alginate beads can potentially be utilized for the encapsulation and controlled release of lipophilic bioactive compounds.

Microgels at fluid-fluid interfaces for food and drinks

Various aspects of microgel adsorption at fluid-fluid interfaces of relevance to emulsion and foam stabilization have been reviewed. The emphasis is on the wider non-food literature, with a view to highlighting how this understanding can be applied to food-based systems. The various different types of microgel, their methods of formation and their fundamental behavioral traits at interfaces are covered. The latter includes aspects of microgel deformation and packing at interfaces, their deformability, size, swelling and de-swelling and how this affects their surface activity and stabilizing properties. Experimental and theoretical methods for measuring and modelling their behaviour are surveyed, including interactions between microgels themselves at interfaces but also other surface active species. It is concluded that challenges still remain in translating all the possibilities synthetic microgels offer to microgels based on food-grade materials only, but Nature's rich tool box of biopolymers and biosurfactants suggests that this field will still open up important new avenues of food microstructure development and control.

Bioaccessibility of Lipophilic Compounds Vehiculated in Emulsions: Choice of Lipids and Emulsifiers

Great efforts have been made to design emulsions considering the need to perform an effective encapsulation, protection, vehiculation, and bioaccessibility of lipophilic compounds. This task can be achieved by manipulating the structure of the emulsion based on the choice of the processes and ingredients of the aqueous phase, interface, and lipid matrix. Thus, the main focus of this perspective is to provide insights into the use of ingredient engineering in manipulating/building emulsion structures that enhance lipophilic compound release and bioaccessibility.