Characterization of mucin – lipid droplet interactions: Influence on potential fate of fish oil-in-water emulsions under simulated gastrointestinal conditions

Impact of saliva incorporation on the rheological properties of in vitro gastric contents formulated from sour cream

Rheological properties of gastric contents depend on the food ingested, and on the volume and composition of secretions from the host, which may vary. This study investigates the impact of saliva regular incorporation in the stomach after a meal on the rheological properties of gastric contents, considering two levels of salivary flow (low = 0.5 and high = 1.5 mL/min). In vitro chymes were obtained by mixing sour cream, simulated gastric fluid, two different volumes of oral fluid (at-rest human saliva, SSF for Simulated Salivary Fluid or water) and adjusting pH at 3. Chymes samples were characterized at 37°C for their particle size and rheological properties. Overall, particle size distribution was not different between samples: incorporating a larger volume of saliva resulted in more heterogeneity, but the surface area moment D[3,2] and volume moment D[4,3] did not differ significantly with the oral fluid type. Shear viscosity of chyme samples was higher when saliva was incorporated, in comparison with water or SSF. In addition, as shown from data extracted atγ ̇ $$ \dot{\gamma} $$  = 20 s-1 the higher the fluid volume the lower the shear viscosity, which is attributed to a dilution effect. However, this dilution effect was attenuated in the case of saliva, most likely due to its composition in organic compounds (e.g., mucins) contributing to the rheological properties of this biological fluid. In these in vitro conditions, both saliva and the salivation rate had a significant but slight impact on the rheological properties of gastric contents (of the order of 1-5 mPa s atγ ̇ $$ \dot{\gamma} $$  = 20 s-1).

Characterization of modified starch-based complexes-stabilized linolenic acid emulsions and their enhanced oxidative stability in vitro gastrointestinal digestion

A new approach of fabricating α-linolenic acid emulsions with enhanced oxidative stability in vitro digestion was established, using covalent octenyl succinic anhydride starch (OSAS)-soy protein (SP)-epigallocatechin-3-gallate (EGCG) complexes as emulsifiers. The physicochemical characteristics and surface morphology of emulsions were mainly characterized by rheological measurements, laser scanning microscope (CLSM) and cryo-scanning electron microscopy (Cryo-SEM). Results indicated that emulsions had dense interfacial layers and strong network structures. As a result, the stability and antioxidant ability of emulsions were improved significantly. In addition, the oxidative stability of emulsions in vitro gastrointestinal digestion was explored. Results showed that emulsions could maintain better oxidative stability owing to antioxidant activity of covalent OSAS-SP-EGCG complexes under gastrointestinal conditions. In particular, lipid hydroperoxide and malondialdehyde contents of emulsions prepared by 1:4 complexes were lower than 0.35 mmol/L and 20.5 nmol/mL, respectively, approximately half those of emulsions stabilized by OSAS (0.65 mmol/L and 39.5 nmol/mL). It was indicated that covalent OSAS-SP-EGCG complexes could effectively inhibit α-linolenic acid oxidation in emulsions during vitro gastrointestinal digestion. This work will provide a theoretical basis for the development of α-linolenic acid emulsions, which will help to broaden application of α-linolenic acid in food industry.

Effect of simulated saliva on rheological and tribological properties of oleogel-in-water HIPEs during oral processing

HYPOTHESIS

High internal phase emulsions (HIPEs) have great potentials in the food industry to control fat consumption. Textural perception of HIPEs during oral processing is strongly influenced by saliva, which has not been systematically investigated. Therefore, we investigated the roles of saliva in the rheological and tribological properties of HIPEs during oral processing.

EXPERIMENTS

HIPEs (O/W) stabilized by oleogel and a protein were fabricated. Small (SAOS) and large (LAOS) amplitude oscillatory shearing measurements and tribological tests were performed, in combination with structural characterization of the emulsions.

FINDINGS

Particle size and CLSM observation indicated that saliva induced coalescence of droplets by weakening the interface and more EC resulted in faster clustering. SAOS tests revealed that emulsions mixed with saliva had weaker structural strength and lower resistance to deformation. Particularly in large deformation, the HIPEs mixed with saliva presented an acceleration in the droplet-droplet structure breakdown, which led to the pronounced strain-thinning behavior and energy dissipation. Tribological curves further revealed that the corporation of saliva contributed to the release of oil to reduce friction coefficient.

Oat Milk Tea Model System: Exploring the Stability of Milk Tea and the Bioaccessibility of Green Tea Polyphenols

Oat milk has become preferential because of its low calorie nature and high dietary fiber content, but its ability to “curdle” when mixed with tea can affect the consumer acceptability for oat milk tea. In this study, a model system for oat milk tea was made by combining oat milk and green tea extract to evaluate the impacts of the oat milk matrix and green tea extract concentration on the stability and polyphenol bioaccessibility. The stability analysis results showed that adding green tea extract to oat milk influenced the stability of the oat milk tea model systems. In contrast, the 3.0% fat oat milk tea model system exhibited a higher stability than the 1.5% fat oat milk tea model system. In simulated gastrointestinal digestive experiments, tea polyphenols in the oat milk tea model systems were relatively stable in oral and stomach digestive stages, while they clearly degraded in the small intestine digestive stage. Furthermore, the bioaccessibility of tea polyphenols was higher for the 3.0% fat oat milk tea model system than for the 1.5% fat oat milk tea model system, especially at low concentrations of green tea extracts (0.05%~0.25%). These results may provide a theoretical reference and data for the formulation of oat milk tea and the bioaccessibility of tea polyphenols in food matrices.

Construction of benzyl isothiocyanate-loaded fish skin gelatin-luteolin compound emulsion delivery system, and its digestion and absorption characteristics

BACKGROUND

Fish skin gelatin (FSG) and luteolin (LUT) were used as composite emulsifiers, and benzyl isothiocyanate (BITC) was used as a model of nutrient delivery to construct a stable emulsion. The storage stability of the FSG-LUT emulsion and its effect on BITC release were investigated both in vitro and ex vivo.

RESULTS

LUT can quench FSG fluorophores statically and form a stable complex through hydrogen bonding and hydrophobic interactions. The FSG-LUT emulsion storage stability and embedding rate were higher than those of the FSG emulsion. The FSG-LUT emulsion microstructure was resistant to oral and gastric digestion, and the BITC retention rate and bioaccessibility were much higher than those of the FSG emulsion. Lastly, the ex vivo everted gut sac of rat intestine study demonstrated that BITC showed the highest absorption in the ileum, and the FSG-LUT emulsion absorbed BITC and sustained a controlled release in a specific position.

CONCLUSION

LUT could form stable complexes with FSG, which improved the stability and bioavailability of BITC in the FSG-LUT emulsion delivery system, and promoted further intestinal BITC absorption. © 2022 Society of Chemical Industry.

Mechanisms of carotenoid intestinal absorption and the regulation of dietary lipids: lipid transporter-mediated transintestinal epithelial pathways

Dietary lipids are key ingredients during cooking, processing, and seasoning of carotenoid-rich fruits and vegetables, playing vitals in affecting the absorption and utilization of carotenoids for achieving their health benefits. Besides, dietary lipids have also been extensively studied to construct various delivery systems for carotenoids, such as micro/nanoparticles, micro/nanoemulsions, and liposomes. Currently, the efficacies of these techniques on improving carotenoid bioavailability are often evaluated using the micellization rate or "bioaccessibility" based on in vitro models. However, recent studies have found that dietary lipids may also affect the carotenoid uptake via intestinal epithelial cells and the efflux of intracellular chyle particles via lipid transporters. An increasing number of studies reveal the varied impact of different dietary lipids on the absorption of different carotenoids and some lipids may even have an inhibitory effect. Consequently, it is necessary to clarify the relationship between the addition of dietary lipids and the intestinal absorption of carotenoid to fully understand the role of lipids during this process. This paper first introduces the intestinal absorption mechanism of carotenoids, including the effect of bile salts and lipases on mixed micelles, the types and regulation of lipid transporters, intracellular metabolizing enzymes, and the efflux process of chyle particles. Then, the regulatory mechanism of dietary lipids during intestinal carotenoid absorption is further discussed. Finally, the importance of selecting the dietary lipids for the absorption and utilization of different carotenoids and the design of an efficient delivery carrier are emphasized. This review provides suggestions for precise dietary carotenoid supplementation and offere an important reference for constructing efficient transport carriers for liposoluble nutrients.

Recent progress in fish oil-based emulsions by various food-grade stabilizers: Fabrication strategy, interfacial stability mechanism and potential application

Fish oil, rich in a variety of long-chain ω-3 PUFAs, is widely used in fortified foods due to its broad-spectrum health benefits. However, its undesired characteristics include oxidation sensitivity, poor water solubility, and fishy off-flavor greatly hinder its exploitation in food field. Over the past two decades, constructing fish oil emulsions to encapsulate ω-3 PUFAs for improving their physicochemical and functional properties has undergone great progress. This review mainly focuses on understanding the fabrication strategies, stabilization mechanism, and potential applications of fish oil emulsions, including fish oil microemulsions, nanoemulsions, double emulsions, Pickering emulsions and emulsion gels. Furthermore, the role of oil-water interfacial stabilizers in the fish oil emulsions stability will be discussed with a highlight on food-grade single emulsifiers and natural complex systems for achieving this purpose. Additionally, its roles and applications in food industry and nutrition field are delineated. Finally, possible innovative food trends and applications are highlighted, such as novel fish oil-based delivery systems construction (e.g., Janus emulsions and nutraceutical co-delivery systems), exploring digestion and absorption mechanisms and enhancing functional evaluation (e.g., nutritional supplement enhancer, and novel fortified/functional foods). This review provides a reference for the application of fish oil-based emulsion systems in future precision diet intervention implementations.

A review of recent progress in improving the bioavailability of nutraceutical-loaded emulsions after oral intake

Increasing awareness of the health benefits of specific constituents in fruits, vegetables, cereals, and other whole foods has sparked a broader interest in the potential health benefits of nutraceuticals. Many nutraceuticals are hydrophobic substances, which means they must be encapsulated in colloidal delivery systems. Oil-in-water emulsions are one of the most widely used delivery systems for improving the bioavailability and bioactivity of these nutraceuticals. The composition and structure of emulsions can be designed to improve the water dispersibility, physicochemical stability, and bioavailability of the encapsulated nutraceuticals. The nature of the emulsion used influences the interfacial area and properties of the nutraceutical-loaded oil droplets in the gastrointestinal tract, which influences their digestion, as well as the bioaccessibility, metabolism, and absorption of the nutraceuticals. In this article, we review recent in vitro and in vivo studies on the utilization of emulsions to improve the bioavailability of nutraceuticals. The findings from this review should facilitate the design of more efficacious nutraceutical-loaded emulsions with increased bioactivity.

Influence of Carboxymethyl Cellulose on the Stability, Rheological Property, and in-vitro Digestion of Soy Protein Isolate (SPI)-Stabilized Rice Bran Oil Emulsion

In this study, carboxymethyl cellulose (CMC) was added to soybean protein isolate (SPI)-stabilized rice bran oil (RBO) emulsion to improve its physicochemical stability and free fatty acid (FFA) release characteristics. RBO emulsions stabilized by SPI and various contents of CMC were prepared and assessed by measuring zeta potential, particle size, transmission, and microstructure, the rheological properties were analyzed by dynamic shear rheometer. In addition, its chemical stability was characterized by a storage experiment, and the FFA release was explored by a simulated gastrointestinal tract (GIT) model. It showed that the negative charge of the droplets of RBO emulsion was increased with increasing CMC content. The decrease in transmission of SPI-stabilized RBO emulsion with increasing CMC content was due to the droplets not being free to move by the special network interaction and an increase in the viscosity. According to the determination of the reactive substances of lipid hydroperoxide and thiobarbituric acid during 30 days storage at 37°C, the chemical stability of the emulsion added with CMC was enhanced compared with the SPI-stabilized RBO emulsion. In-vitro digestion studies not only evaluated the structural changes of RBO emulsions at different stages, but also found that RBO emulsion with CMC showed a higher level of free fatty acids release in comparison with that without CMC. It indicated that the utilization of CMC can improve the bioavailability of RBO emulsions.

Peptide-Mucin Binding and Biosimilar Mucus-Permeating Properties

This study aimed to understand the role of the mucus layer (a biological hydrogel) in the transport mechanisms of peptides. Using established in vitro models, the mucin-binding activity and mucus-permeating property of peptides were determined. Uncharged peptides with relatively high hydrophilicity, including MANT, TNGQ, and PASL, as well as cationic peptides, including KIPAVF and KMPV, possessed strong mucin-binding activity. Contrarily, uncharged peptides with high hydrophobicity index, including YMSV and QIGLF, exhibited weak mucin-binding activity. Only TNGQ, which has high Boman index and hydrophilicity, showed a high biosimilar mucus-permeating property with a permeability of 96 ± 30% after 60 min. TNGQ showed the potential for high bioavailability due to the high mucin-binding and biosimilar mucus-permeating activities.

Effects of tocopherols on the stability of flaxseed oil-in-water emulsions stabilized by different emulsifiers: Interfacial partitioning and interaction

The potential effects of tocopherols (100 μM in emulsions) on the physicochemical stability of whey protein isolate (WPI), soy lecithin (SL), or Tween 20 (TW) stabilized flaxseed oil (FO)-in-water emulsions were investigated. During the storage (18 days at 55 ℃), the particle size, microstructure, and multiple light scattering results showed WPI-stabilized emulsions exhibited better physical stability when tocopherols were added hydroperoxides and TBARS concentration in TW-stabilized emulsions were higher than those of SL or WPI, which were suppressed differently by tocopherols. Among homologues, δ-tocopherol was more effective in inhibiting lipid oxidation than α-tocopherol, which was related to the higher interface partitioning. Moreover, the increased interfacial tension indicated tocopherols, especially δ-tocopherol, were adsorbed on the interface and interacted with WPI or SL via hydrophobic or electrostatic interactions determined by isothermal titration calorimetry. Our results suggest tocopherols are more applicable in WPI emulsion systems to achieve steady-state delivery of ALA.

Fabrication and characterization of β-carotene emulsions stabilized by soy oleosin and lecithin mixtures with a composition mimicking natural soy oleosomes

Natural soy oleosomes are known to have a remarkable stability, given the advantage of their sophisticated membrane. The aim of the present study is to examine the concept of fabricating a β-carotene emulsion stabilized by soy oleosin (OLE) and lecithin (LEC) mixtures mimicking the membrane composition of soy oleosomes while providing preferable stability and bioaccessibility. For this, the fabricated emulsion was characterized in terms of droplet size distribution, and emulsion structure, stability and digestion (release and absorption of lipophilic β-carotene). Compared to SPI/LEC (10 : 1) stabilized emulsions, the OLE/LEC (10 : 1) mixture stabilized emulsion exhibited the highest emulsifying activity index (EAI) and emulsifying stability index (ESI) values, and higher encapsulation efficiency. Results show that the β-carotene emulsion stabilized by OLE and LEC mixtures at the ratio of 10 : 1 (w/w) has the most uniform droplet distribution and highest stability. The in vitro gastrointestinal digestion test revealed that the β-carotene emulsion stabilized by OLE and LEC mixtures was digested more rapidly than the emulsion stabilized by soy protein isolate (SPI) and LEC mixtures. In turn, the bioaccessibility and cellular uptake of β-carotene were enhanced, resulting in a higher absorption, a desirable feature of nutrition delivery systems. Our results demonstrated a promising way to fabricate emulsions mimicking natural soy oleosomes.

Purified mucins in drug delivery research

One of the main challenges in the field of drug delivery remains the development of strategies to efficiently transport pharmaceuticals across mucus barriers, which regulate the passage and retention of molecules and particles in all luminal spaces of the body. A thorough understanding of the molecular mechanisms, which govern such selective permeability, is key for achieving efficient translocation of drugs and drug carriers. For this purpose, model systems based on purified mucins can contribute valuable information. In this review, we summarize advances that were made in the field of drug delivery research with such mucin-based model systems: First, we give an overview of mucin purification procedures and discuss the suitability of model systems reconstituted from purified mucins to mimic native mucus. Then, we summarize techniques to study mucin binding. Finally, we highlight approaches that made use of mucins as building blocks for drug delivery platforms or employ mucins as active compounds.

Nanostructured lipid carriers for the encapsulation of phloretin: preparation and in vitro characterization studies

Phloretin is a powerful antioxidant with many effects, such as anti-cancer, anti-inflammatory, promoting cell renewal, delaying aging and so on. However, the application of phloretin was limited by its low water solubility, low absorption in vivo and unstable properties. A phloretin-loaded nanostructured lipid carrier was designed with a high-pressure homogenization technique. The mean particle size of phloretin NLC was 137.40 ± 3.27 nm, and the Polydispersity index (PdI) value was 0.237 ± 0.005. The encapsulation efficiency was 96.68% ± 0.06%. Transmission electron microscopy images showed that the phloretin-loaded nanostructured lipid carriers were spherical. Phloretin in NLC showed a sustained release pattern in vitro. The results showed that phloretin NLC is more suitable for absorption than phloretin ethanol solution, and NLC can be a promising carrier for phloretin in the food industry.

Bioaccessibility of carotenoids and antioxidant capacity of seed-used pumpkin byproducts powders as affected by particle size and corn oil during in vitro digestion process

Powders made from seed-used pumpkin flesh (SUPF) are potential sources of carotenoids. In this study, unexplored effects of particle size and corn oil on bioaccessible amounts of carotenoids and antioxidant capacity of SUPF powders during in vitro digestion process were investigated. Overall, total carotenoid relative bioaccessibility (TCRB) of 100 mesh-sized powder (100 MP, 15.46%) was higher than that of 18 mesh-sized powder (18 MP, 12.94%). With the addition of 2% corn oil, TCRB increased 108.35% (18 MP) and 88.55% (100 MP), respectively. Lutein (≥27160 µg/100 g) and β-carotene (≥5192 µg/100 g) were main carotenoid monomers in SUPF and significantly correlated with DPPH radical scavenging activity of digestive supernatant (p < 0.05). Notably, DPPH radical scavenging activity of 18 MP increased 96.54% with corn oil. These results implied that smaller particle size and oil addition could improve bioaccessible amounts of carotenoids and antioxidant capacity of SUPF powders.

Pectin-peptide complexes ameliorated physicochemical stabilities and in vitro digestion abilities of β-carotene loaded emulsions

To improve the stabilities of low methoxy pectin (LMP) stabilized O/W emulsions for the delivery of bioactive substances, LMP was firstly modified with soy peptide (SP), corn peptide (CP) and whey protein peptide (WPP), respectively, by using dry-heat method, then the properties of LMP-peptide complexes stabilized O/W emulsions were characterized and the in vitro digestion of emulsions with β-carotene was test to evaluate the potential applications. LMP-peptide complexes were formed by covalent bonds according to FT-IR spectroscopy. Compared to LMP stabilized emulsions, LMP-peptide complexes stabilized emulsions had smaller droplet sizes and higher stabilities in the changed pH value, temperature and ionic strength. Based on the results of in vitro digestion tests, LMP-SP and LMP-WPP obtained by incubating LMP with peptides at 60 °C for 12 h at the weight ratio of 4:1 were more suitable for the preparation of O/W emulsions to deliver camellia oil and β-carotene.

Surface decoration of neohesperidin-loaded nanoliposome using chitosan and pectin for improving stability and controlled release

The aim of this study was to improve the physicochemical stability of neohesperidin (NH) using nanoliposomal encapsulation in association with surface decoration strategy employing chitosan (CH) and pectin (P). Different nanoliposomal systems, i.e. NH-loaded nanoliposome (NH-NL), CH-coated NH-NL (CH-NH-NL), and P-coated CH-NH-NL (P-CH-NH-NL) were characterized through DLS, HPLC, TEM, and FTIR. The results confirmed good encapsulation efficiency (>90%) and successful layer formation with nano-sized and spherical carrier. Both CH-NL and P-CH-NL exhibited better physicochemical stability than NL under storage, thermal, pH, ionic, UV, oxidative, and serum conditions. In vitro mucin adsorption study revealed that CH-NL (60%) was more effective in mucoadhesion followed by P-CH-NL (46%) and NL (41%). Furthermore, P-CH-NL showed better performance in NH retention under different food simulants compared to CH-NH-NL and NH-NL, in which the release was mainly governed by the diffusion process. Thus, the P-CH conjugated nanoliposome could be a promising nano-carrier for neohesperidin.

Structural characterization and stability study of green synthesized starch stabilized silver nanoparticles loaded with isoorientin

Isoorientin (Iso) is a natural flavonoid, the effect of metal nanoparticles loaded with it was unknown. In this study, silver nanoparticles (AgNPs) were synthesized by corn starch and sodium citrate with the green synthesis method, and the structural characterization and stability of AgNPs loaded with Iso (AgNPs-Iso) were examined by UV-vis spectroscopy and zetasizer. Results showed that AgNPs (65 ± 0.87 nm, spheres) successfully loaded with Iso (117 ± 2.13 nm, loading efficiency: 76.60%). There are no significant changes of the stability of AgNPs and AgNPs-Iso in pH 5-9 and 0-0.30 M of NaCl solution. AgNPs-Iso was more stable than AgNPs in the simulated gastrointestinal digestion in vitro. Furthermore, AgNPs-Iso showed the lower erythrocytes hemolysis ratio and cytotoxicity, and exhibited a notably inhibitive effect on α-glucosidase and pancreatic lipase. Therefore, this study could provide the basic support for the further development of highly stable and lowly cytotoxic AgNPs-Iso on Type II diabetes and obesity.

Impact of curcumin delivery system format on bioaccessibility: nanocrystals, nanoemulsion droplets, and natural oil bodies

Curcumin, a hydrophobic yellow-orange crystalline substance derived from plants, is claimed to exhibit a broad range of biological activities. Its application in functional foods and beverages is often limited by its low solubility in aqueous media, chemical instability, and low bioavailability. Previously, we have shown that curcumin can be successfully loaded into emulsions using the pH-shift method. In this study, we compared the efficacy of curcumin crystals dispersed in water (control) with three delivery systems produced using the pH-shift method: curcumin nanocrystals; curcumin-loaded nanoemulsions; and curcumin-loaded soy oil bodies. The nanoemulsions and oil bodies formed creamy yellow dispersions that were stable to creaming, whereas the nanocrystals formed a cloudy yellow-orange suspension that was prone to sedimentation. The gastrointestinal fate of the delivery systems was assessed using a static in vitro digestion model consisting of mouth, stomach, and small intestine phases. The nanoemulsions and oil bodies were rapidly and fully digested, while the nanocrystals were not. All three systems were relatively stable to chemical transformation in the in vitro digestion model. The nanocrystals gave a low bioaccessibility but the other two systems gave a high bioaccessibility, which was attributed to their ability to form mixed micelles to solubilize the curcumin. These results have important implications for the creation of more effective delivery systems for curcumin.

Role of Mucin in Behavior of Food-Grade TiO2 Nanoparticles under Simulated Oral Conditions

Fine titanium dioxide (TiO₂) particles have been used as additives (E171) to modify the optical properties of foods and beverages for many years. Commercial TiO₂ additives, however, often contain a significant fraction of nanoparticles (diameter <100 nm), which has led to some concern about their potentially adverse health effects. At present, relatively little is known about how the characteristics of TiO₂ particles are altered as they travel through the human gastrointestinal tract. Alterations in their electrical characteristics, surface composition, or aggregation state would be expected to alter their gastrointestinal fate. The main focus of this study was, therefore, to characterize the behavior of TiO₂ particles under simulated oral conditions. Changes in the aggregation state and electrical characteristics were monitored using particle size, ζ-potential, turbidity, and electron microscopy measurements, whereas information about mucin-particle interactions were obtained using isothermal titration calorimetry and surface-enhanced Raman spectroscopy. Our results indicate that there was a strong interaction between TiO₂ and mucin: mucin absorbed to the surfaces of the TiO₂ particles and reduced their tendency to aggregate. The information obtained in this study is useful for better understanding the gastrointestinal fate and potential toxicity of ingested inorganic particles.

Fabrication of plant-based vitamin D3-fortified nanoemulsions: influence of carrier oil type on vitamin bioaccessibility

The influence of carrier oil type (corn, fish, or flaxseed oil) on the production, stability, and simulated gastrointestinal behavior of vitamin-fortified nanoemulsions was studied. The nanoemulsions were formulated using pea protein as an emulsifier since there is increasing interest in substituting artificial and animal-based food ingredients with natural plant-based alternatives. Lipid digestion and vitamin D3 bioaccessibility were measured when the nanoemulsions were subjected to a three-stage in vitro gastrointestinal tract: oral, gastric, and small intestinal. The majority of all three lipids were digested within the first few minutes in the simulated small intestine, with the corn oil nanoemulsions being digested faster than the fish or flaxseed oils. Moreover, a greater fraction of triglycerides were digested by the end of the small intestine for the corn oil than for the fish and flaxseed oils. For the different carrier oils, vitamin bioaccessibility was ranked: corn oil > flaxseed oil ≈ fish oil. These results suggest that monounsaturated-rich oils (such as corn oil) are better for encapsulating and delivering vitamin D3 than polyunsaturated-rich ones (such as flaxseed or fish oil). The insights gained here may aid in the formulation of more efficacious vitamin-fortified foods and beverages from plant-derived ingredients.

Bioaccessibility and stability of β-carotene encapsulated in plant-based emulsions: impact of emulsifier type and tannic acid

The effect of two plant-based emulsifiers (quillaja saponin, QS and gum arabic, GA) and a polyphenol (tannic acid) on the formation, stability, digestibility, and β-carotene (BC) bioaccessibility of flaxseed oil-in-water emulsions was investigated.

Buccal Bullfrog (Rana catesbeiana Shaw) Oil Emulsion: A Mucoadhesive System Intended for Treatment of Oral Candidiasis

Oral candidiasis (OC) is an infectious disease caused by microorganisms of the genus Candida, leading to lesions in the buccal cavity. Its treatment consists of the administration of topical or systemic antifungal agents, which may compromise the patient compliance due to its side effects, highlighting the need for alternative treatments. In this scenario, bullfrog oil, an animal oil composed of a pool of saturated and unsaturated fatty acids, is introduced as a potential antifungal raw material. Thus, the aim of this work was to produce a mucoadhesive emulsified system able to deliver the bullfrog oil in the buccal cavity to treat the OC. The emulsion was produced and characterized by visual inspection, droplet size, polydispersity index (PdI), and zeta potential over the course of 60 days. In addition, its mucoadhesive ability was evaluated using an in vitro mucin model. The antifungal activity, evaluated by the broth microdilution assay and the biocompatibility, performed against human erythrocytes, were also carried out. The emulsion showed a droplet size of 320.79 ± 35.60 nm, a PdI of 0.49 ± 0.08, and a zeta potential of -38.53 ± 6.23 mV, with no significant changes over 60 days. The mucoadhesive properties of the system was improved by the use of pharmaceutical excipients. The antifungal activity showed that the bullfrog oil and the emulsion were able to inhibit the growth of different Candida species. Furthermore, the emulsion showed no significant hemolytic effect. Overall, the system showed suitable physicochemical characteristics and biocompatibility, with substantial in vitro antifungal activity, suggesting that this system can be further investigated for OC treatment.

Microgel-in-Microgel Biopolymer Delivery Systems: Controlled Digestion of Encapsulated Lipid Droplets under Simulated Gastrointestinal Conditions

Structural design principles are increasingly being used to develop colloidal delivery systems for bioactive agents. In this study, oil droplets were encapsulated within microgel-in-microgel systems. Initially, a nanoemulsion was formed that contained small whey protein-coated oil droplets ( d₄₃ = 211 nm). These oil droplets were then loaded into either carrageenan-in-alginate (O/M_C/M_A) or alginate-in-carrageenan (O/M_A/M_C) microgels. A vibrating nozzle encapsulation unit was used to form the smaller inner microgels ( d₄₃ = 170-324 μm), while a hand-held syringe was used to form the larger outer microgels ( d₄₃ = 2200-3400 μm). Calcium alginate microgels (O/M_A) were more stable to simulated gastrointestinal tract (GIT) conditions than potassium carrageenan microgels (O/M_C), which was attributed to the stronger cross-links formed by divalent calcium ions than the monovalent potassium ions. As a result, the microgel-in-microgel systems had different gastrointestinal fates depending upon the nature of the external microgel phase; i.e., the O/M_C/M_A system was more resistant to rupture than the O/M_A/M_C system. The rate of lipid digestion under simulated small intestine conditions decreased in the following order: free oil droplets > O/M_C > O/M_A > O/M_A/M_C > O/M_C/M_A. This effect was attributed to differences in the integrity and dimensions of the microgels in the small intestine, because a hydrogel network surrounding the oil droplets inhibits lipid hydrolysis by lipase. The structured microgels developed in this study may have interesting applications for the protection or controlled release of bioactive agents.

Influence of Homogenization and Thermal Processing on the Gastrointestinal Fate of Bovine Milk Fat: In Vitro Digestion Study

Dairy lipids are an important source of energy and nutrients for infants and adults. The dimensions, aggregation state, and interfacial properties of fat globules in raw milk are changed by dairy processing operations, such as homogenization and thermal processing. These changes influence the behavior of fat globules within the human gastrointestinal tract (GIT). The gastrointestinal fate of raw milk, homogenized milk, high temperature short time (HTST) pasteurized milk, and ultrahigh temperature (UHT) pasteurized milk samples was therefore determined using a simulated GIT. The properties of particles in different regions of the GIT depended on the degree of milk processing. Homogenization increased the initial lipid digestion rate but did not influence the final digestion extent. Thermal processing of homogenized milk decreased the initial rate and final extent of lipid digestion, which was attributed to changes in interfacial structure. These results provide insights into the impact of dairy processing on the gastrointestinal fate of milk fat.

50years of oral lipid-based formulations: Provenance, progress and future perspectives

Lipid based formulations (LBF) provide well proven opportunities to enhance the oral absorption of drugs and drug candidates that sit close to, or beyond, the boundaries of Lipinski's 'rule-of-five' chemical space. Advantages in permeability, efflux and presystemic metabolism are evident; however, the primary benefit is in increases in dissolution and apparent intestinal solubility for lipophilic, poorly water soluble drugs. This review firstly details the inherent advantages of LBF, their general properties and classification, and provides a brief retrospective assessment of the development of LBF over the past fifty years. More detailed analysis of the ability of LBF to promote intestinal solubilisation, supersaturation and absorption is then provided alongside review of the methods employed to assess formulation performance. Critical review of the ability of simple dispersion and more complex in vitro digestion methods to predict formulation performance subsequently reveals marked differences in the correlative ability of in vitro tests, depending on the properties of the drug involved. Notably, for highly permeable low melting drugs e.g. fenofibrate, LBF appear to provide significant benefit in all cases, and sustained ongoing solubilisation may not be required. In other cases, and particularly for higher melting point drugs such as danazol, where re-dissolution of crystalline precipitate drug is likely to be slow, correlations with ongoing solubilisation and supersaturation are more evident. In spite of their potential benefits, one limitation to broader use of LBF is low drug solubility in the excipients employed to generate formulations. Techniques to increase drug lipophilicity and lipid solubility are therefore explored, and in particular those methods that provide for temporary enhancement including lipophilic ionic liquid and prodrug technologies. The transient nature of these lipophilicity increases enhances lipid solubility and LBF viability, but precludes enduring effects on receptor promiscuity and off target toxicity. Finally, recent efforts to generate solid LBF are briefly described as a means to circumvent the need to encapsulate in soft or hard gelatin capsules, although the latter remain popular with consumers and a proven means of LBF delivery.