Peach Palm Fruit (Bactris gasipaes) Peel: A Source of Provitamin A Carotenoids to Develop Emulsion-Based Delivery Systems

The peach palm fruit (Bactris gasipaes) peel is a byproduct after fruit consumption. The peel flour of two varieties (yellow and red) was separately obtained by hot air drying and was subsequently milled. The proximate analysis showed that the red variety exhibited higher protein, fat, and fiber contents than the yellow one. A higher carotenoid (836.5 ± 24.5 μg/g), phenolic compounds (83.17 ± 1.76 mg GAE/100 g), and provitamin A activity (33.10 ± 0.83 μg retinol/g) were found in the cooked red variety. The carotenoid and phenolic compositions were analyzed by HPLC-PDA-MS, finding β-carotene and γ-carotene to be major compounds. The effect of thermal treatment increased the amount of these provitamin A carotenoids and lycopene, which were detected only in the red variety. Among phenolic compounds, procyanidin dimer (isomer I), feruloyl quinic acid, and several apigenin C-hexosides were identified as major constituents of peach palm epicarp. A carotenoid-rich emulsion-based delivery system was obtained after the optimization (RSM model) of carotenoid extraction with ultraturrax and sunflower oil and further development of an ultrasound-assisted emulsion. The best conditions for a stable emulsion were 73.75% water, 25% carotenoid-rich oil extract, 1.25% emulsifiers, and 480 W of ultrasonic power for 5 min. The optimized emulsion had a total carotenoid content of 67.61 μg/g, Provitamin A activity of 3.23 ± 0.56 μg RAE/g, droplet size of 502.23 nm, polydispersity index of 0.170, and zeta potential of -32.26 mV. This emulsion was chemically and physically stable for 35 days at 30 ± 2 °C, showing potential as a food additive with biofunctional properties. The strategy here developed is an economical and environmentally friendly process that allows the reuse of the byproduct of B. gasipaes.

Hyaluronic acid-poly(glyceryl)10-stearate nanoemulsion for co-delivery of fish oil and resveratrol: Enhancing bioaccessibility and antioxidant potency

Hyaluronic acid (HA), an endogenous polysaccharide comprising alternating D-glucuronic acid and N-acetylglucosamine units, is renowned for its high hydrophilicity, biocompatibility, and biodegradability. These attributes have rendered HA invaluable across medical and drug delivery fields. HA can be altered through physical, chemical, or enzymatic methods to improve the properties of the modified substances. In this work, we synthesized a derivative via the esterification of HA with poly(glyceryl)10-stearate (PG10-C18), designated as HA-PG10-C18. This novel derivative was employed to fabricate a nano co-delivery system (HA-PG10-C18@Res-NE) for fish oil and resveratrol (Res), aiming to enhance their stability and bioaccessibility. An exhaustive investigation of HA-PG10-C18@Res-NE revealed that the HA-modified system displayed superior physicochemical stability, notably in withstanding oxidation and neutralizing free radicals. Moreover, in vitro simulated digestion underscored the system's enhanced bioaccessibility of Res and more efficient release of free fatty acids. These outcomes underscore the strategic advantage of HA in modifying PG10-C18 for nanoemulsion formulation. Consequently, HA-PG10-C18 stands as a promising emulsifier for encapsulating lipophilic bioactives in functional foods, nutraceuticals, and pharmaceuticals.

Eugenol and Aloe vera blended natural wax-based coating for preserving postharvest quality of Kaji lemon (Citrus jambhiri)

Edible coatings on fruits and vegetables preserve postharvest quality by reducing water loss and lowering respiration, and metabolic activities. The primary objectives of this study were to develop composite coating formulations using natural waxes (carnauba and shellac wax), eugenol nanoemulsion, and Aloe vera gel, and assess the potential impacts of the coating formulations on the postharvest quality and shelf-life of the Kaji lemon. The results show that eugenol nanoemulsion and Aloe vera gel enhanced the physico-chemical, antimicrobial and antioxidant properties of the developed coating. Notably, the fruits coated with optimized nanocomposite of wax with eugenol and aloe vera gel inclusion (SW + CW/EuNE-20/AVG-2) showed the lowest weight loss (16.56%), while the coatings of wax with only aloe vera gel (SW + CW/AVG-2) exhibited the highest firmness (48 N), in contrast to the control fruit, which had 27.33% weight loss and 9.6 N firmness after 28 days of storage, respectively.

Performance of β-carotene-loaded nanostructured lipid carriers under dynamic in vitro digestion system: Influence of the emulsifier type

A better understanding of how emulsifier type could differently influence the behavior of nanostructured lipid carriers (NLC) under the gastrointestinal digestion process, as well as at the cellular level, is of utmost importance for the NLC-based formulations' optimization and risk assessment in the food field. In this study, NLC composed by fully hydrogenated soybean and high-oleic sunflower oils were prepared using soy lecithin (NLC Lβ) or Tween 80 (NLC Tβ) as an emulsifier. β-Carotene was entrapped within NLC developed as a promising strategy to overcome β-carotene's low bioavailability and stability. The effect of emulsifier type on the digestibility of β-carotene-loaded NLC was evaluated using an in vitro dynamic digestion model mimicking peristalsis motion. The influence of β-carotene-loaded NLC on cell viability was assessed using Caco-2 cells in vitro. NLC Tβ remained stable in the gastric compartment, presenting particle size (PS) similar to the initial NLC (PS: 245.68 and 218.18 nm, respectively), while NLC Lβ showed lower stability (PS > 1000 nm) in stomach and duodenum phases. NLC Tβ also provided high β-carotene protection and delivery capacity (i.e., β-carotene bioaccessibility increased 10-fold). Based on the results of digestion studies, NLC Tβ has shown better physical stability during the passage through the in vitro dynamic gastrointestinal system than NLC Lβ. Moreover, the developed NLC did not compromise cell viability up to 25 µg/mL of β-carotene. Thus, the NLC developed proved to be a biocompatible structure and able to incorporate and protect β-carotene for further food applications. PRACTICAL APPLICATION: The findings of this study hold significant implications for industrial applications in terms of developing nanostructured lipid carriers from natural raw materials widely available and used to produce other lipid-based products in the food industry, as an alternative to synthetic ones. In this respect, the β-carotene-loaded NLC developed in this study would find a great industrial application in the food industry, which is in constant search to develop functional foods capable of increasing the bioavailability of bioactive compounds.

Encapsulation of Black Rice Bran Extract in a Stable Nanoemulsion: Effects of Thermal Treatment, Storage Conditions, and In Vitro Digestion

This study aimed to improve the dispersibility of phenolic compounds from black rice bran through the encapsulation process within nanoemulsion. The study focused on assessing the stability of the nanoemulsions, which were prepared using a combination of surfactants with distinct hydrophilic-lipophilic balance (HLB) values and sunflower oil under different thermal treatments and storage conditions. The study revealed a significant correlation between the mixed surfactant HLB value and the nanoemulsions properties, including average particle size, polydispersity index (PDI), and ζ-potential. Specifically, an increase in the HLB value was associated with a decrease in the initial average particle size. The encapsulated polyphenols exhibited remarkable stability over a storage period of up to 30 days at different temperatures with no significant changes observed in particle size or PDI. The study also investigated the impact of different ionic strengths (0.2, 0.5, and 1.00 mol L-1 NaCl) on the physical stability and antioxidant black rice bran extract nanoemulsion, and the results revealed that adding NaCl influenced the particle size and surface charge of the nanoemulsions. Total phenolic content and DPPH results demonstrated a significant impact of salt concentration on antioxidant properties, with varying trends observed among the HLB formulations. Furthermore, the behavior of the encapsulated extracts during digestion was examined, and their antioxidant activity was evaluated.

Enhanced in vivo absorption and biodistribution of curcumin loaded into emulsions with high medium-chain triglyceride content

The health benefits of curcumin have been demonstrated by several clinical studies, but its low bioavailability compromises its functionality. In this regard, emulsions have proven to be effective encapsulation systems for curcumin. Nevertheless, emulsions with a high oil content (50%) may offer some advantages due to the large amount of compound they can incorporate. Therefore, the aim of this work was to study the pharmacokinetics and biodistribution of curcumin when carried in optimized emulsions containing 50% MCT oil and a plant-based emulsifier (soybean lecithin) at 2 h or 4 h post-oral administration to rats. The most stable emulsion was obtained using 50% of oil and a surfactant-oil-ratio 0.1, through a microfluidization process. After the oral administration of the systems (150 mg curcumin/kg body weight), curcumin glucuronide was the main compound present in plasma (AUC0-t = 1556.3 ng·h·ml-1), especially at 2-4 h post-administration. The total curcuminoid bioavailability was increased by 10.6-fold when rats were fed with the curcumin emulsion rather than with a control suspension. Moreover, rats fed with the emulsion showed the highest accumulation of free curcuminoids, which present the highest biological activity, in the liver (129 ng curcumin/g tissue) and brown adipose tissue (193 ng curcumin/g tissue). The obtained results are of great interest since the presence of curcumin in the brown adipose tissue has been shown to play a relevant role in the prevention of obesity and its related metabolic disorders.

Influence of different electrolytes and oils on the stability of W1/O/W2 double emulsion during storage and in vitro digestion

The aim of this study is to formulate a stable water-in-oil-in-water (W1/O/W2) double emulsion using different types of oils and electrolytes. W1/O was formulated with different electrolyte solutions (W1) dispersed in various oils (O) using polyglycerol polyricinoleate as a stabilizer. External aqueous phase was Tween-80 (W2), and W1/O dispersed in W2 was used. The emulsion containing NaCl or MgCl2 exhibited high encapsulation efficiency (EE) and maintained particle size. Regarding the oil type, the emulsion with MCT oil showed a small droplet size and a high viscosity and EE, presenting a stable droplet distribution in optical observation. The stability of emulsion containing NaCl was maintained during the in vitro digestion experiments. MCT oil, NaCl and MgCl2 have the potential to produce stable double emulsions for storage stability and in vitro digestion studies. The findings would be useful for preparing stable double emulsions used in the food and cosmetic industries.

Emulsion-Based Delivery Systems to Enhance the Functionality of Bioactive Compounds: Towards the Use of Ingredients from Natural, Sustainable Sources

In recent years, the trend in the population towards consuming more natural and sustainable foods has increased significantly. This claim has led to the search for new sources of bioactive compounds and extraction methods that have less impact on the environment. Moreover, the formulation of systems to protect these compounds is also focusing on the use of ingredients of natural origin. This article reviews novel, natural alternative sources of bioactive compounds with a positive impact on sustainability. In addition, it also contains information on the most recent studies based on the use of natural (especially from plants) emulsifiers in the design of emulsion-based delivery systems to protect bioactive compounds. The properties of these natural-based emulsion-delivery systems, as well as their functionality, including in vitro and in vivo studies, are also discussed. This review provides relevant information on the latest advances in the development of emulsion delivery systems based on ingredients from sustainable natural sources.

Effect of the Emulsifier Used in Dunaliella salina-Based Nanoemulsions Formulation on the β-Carotene Absorption and Metabolism in Rats

SCOPE

Microalgae such as Dunaliella salina are a potential sustainable source of natural β-carotene due to their fast growth and high adaptability to environmental conditions. This work aims to evaluate the effect of the incorporation of β-carotene from this alga into different emulsifier-type nanoemulsions (soybean lecithin [SBL], whey protein isolate [WPI], sodium caseinate [SDC]) on its absorption, metabolization, and biodistribution in rats.

METHODS AND RESULTS

Nanoemulsions formulated with different emulsifiers at 8% concentration are obtained by five cycles of microfluidization at 130 mPa, then expose to an in vitro digestion or orally administer to rats. Feeding rats with nanoemulsions improves β-carotene uptake compared to control suspension, especially using SDC and WPI as emulsifiers. A greater presence of β-carotene and retinol in the intestine, plasma, and liver is observed, being the liver the tissue that shows the highest accumulation. This fact can be a consequence of the smaller droplets that protein-nanoemulsions present compared to that with SBL in the intestine of rats, which promote faster digestibility and higher β-carotene bioaccessibility (35%-50% more) according to the in vitro observations.

CONCLUSIONS

Nanoemulsions, especially those formulated with protein emulsifiers, are effective systems for increasing β-carotene absorption, as well as retinol concentration in different rat tissues.

Enhancing in vivo retinol bioavailability by incorporating β-carotene from alga Dunaliella salina into nanoemulsions containing natural-based emulsifiers

The use of microalgae as a source of bioactive compounds has gained interest since they present advantages vs higher plants. Among them, Dunaliella salina is one of the best sources of natural β-carotene, which is the precursor of vitamin A. However, β-carotene shows reduced oral bioavailability due to its chemical degradation and poor absorption. The work aimed to evaluate the influence of the emulsifier and oil concentration on the digestive stability of Dunaliella Salina-based nanoemulsions and study their influence on the digestibility and the β-carotene bioaccessibility. In addition, the effect of the emulsifier nature on the absorption of β-carotene and its conversion to retinol in vivo was also investigated. Results showed that the coalescence observed in soybean lecithin nanoemulsion during the gastrointestinal digestion reduced the digestibility and β-carotene bioaccessibility. In contrast, whey protein nanoemulsion that showed aggregation in the gastric phase could be redispersed in the intestinal phase facilitating the digestibility and bioaccessibility of the compound. In vivo results confirmed that whey protein nanoemulsion increased the bioavailability of retinol to a higher extent (C_max 685 ng/mL) than soybean lecithin nanoemulsion (C_max 394 ng/mL), because of an enhanced β-carotene absorption.

Enhancing the Gastrointestinal Stability of Curcumin by Using Sodium Alginate-Based Nanoemulsions Containing Natural Emulsifiers

Curcumin presents interesting biological activities but low chemical stability, so it has been incorporated into different emulsion-based systems in order to increase its bioaccessibility. Many strategies are being investigated to increase the stability of these systems. Among them, the use of polysaccharides has been seen to highly improve the emulsion stability but also to modulate their digestibility and the release of the encapsulated compounds. However, the effect of these polysaccharides on nanoemulsions depends on the presence of other components. Then, this work aimed to study the effect of alginate addition at different concentrations (0-1.5%) on the gastrointestinal fate and stability of curcumin-loaded nanoemulsions formulated using soybean lecithin or whey protein as emulsifiers. Results showed that, in the absence of polysaccharides, whey protein was more effective than lecithin in preventing curcumin degradation during digestion and its use also provided greater lipid digestibility and higher curcumin bioaccessibility. The addition of alginate, especially at ≥1%, greatly prevented curcumin degradation during digestion up to 23% and improved the stability of nanoemulsions over time. However, it reduced lipid digestibility and curcumin bioaccessibility. Our results provide relevant information on the use of alginate on different emulsifier-based nanoemulsions to act as carriers of curcumin.

Recent progresses in the delivery of β-carotene: From nano/microencapsulation to bioaccessibility

Beta-carotene (BC) as an efficient pro-vitamin is effective in improving vision, immune system and cognitive function as well as preventing coronary diseases and cancer. However, besides its poor chemical stability, the high lipophilic nature of BC reduces its dispersibility and consequently bioavailability which limits its application into food, pharmaceutical and nutraceuticals. Different carriers with vesicular or particulate structures have been studied and utilized for promoting BC solubility, dispersibility, and protection against diverse operational or environmental stresses and also controlling BC release and subsequent bioaccessibility. The current study, therefore reviews different micro/nanocarriers reported on BC encapsulation with special focusing on its bioavailability. Liposomal structures have been successfully used for enhancing BC stability and bioavailability. Besides, emulsion-based carriers including Pickering emulsions, nanoemulsions and microemulsions have been widely evaluated for BC encapsulation and protection. In addition, lipid-based nanoparticles and nanostructural carriers have also been applied successfully for this context. Moreover, gel structures including emulgels, hydrogels and oleogels are studied in some researches. Most of these delivery systems led to higher hydro-solubility and dispersibility of BC which consequently increased its bioavailability; thereupon could promote its application into food, cosmetic and nutraceutical products. However, for remarkable incorporation of BC and other bioactive compounds into edible products, the safety and toxicological aspects of these delivery system especially those designed in nano scale should be addressed in the further researches.

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.

Nano-enabled plant-based colloidal delivery systems for bioactive agents in foods: Design, formulation, and application

Consumers are becoming increasingly aware of the impact of their dietary choices on the environment, animal welfare, and health, which is causing many of them to adopt more plant-based diets. For this reason, many sectors of the food industry are reformulating their products to contain more plant-based ingredients. This article describes recent research on the formation and application of nano-enabled colloidal delivery systems formulated from plant-based ingredients, such as polysaccharides, proteins, lipids, and phospholipids. These delivery systems include nanoemulsions, solid lipid nanoparticles, nanoliposomes, nanophytosomes, and biopolymer nanoparticles. The composition, size, structure, and charge of the particles in these delivery systems can be manipulated to create novel or improved functionalities, such as improved robustness, higher optical clarity, controlled release, and increased bioavailability. There have been major advances in the design, assembly, and application of plant-based edible nanoparticles within the food industry over the past decade or so. As a result, there are now a wide range of different options available for creating delivery systems for specific applications. In the future, it will be important to establish whether these formulations can be produced using economically viable methods and provide the desired functionality in real-life applications.

Interfacial characteristics and in vitro digestion of emulsion coated by single or mixed natural emulsifiers: lecithin and/or rice glutelin hydrolysates

BACKGROUND

The interfacial characteristics and in vitro digestion of emulsion were related to emulsifier type. The mean droplet diameter, ζ-potential, microstructure, interfacial tension, Quartz crystal microbalance with dissipation (QCM-D) and in vitro gastrointestinal fate of emulsions stabilized by soybean lecithin, hydrolyzed rice glutelin (HRG) and their mixture were researched.

RESULTS

The value of interfacial tension was much more dramatically declined for the sample containing 20 g kg^-1 of HRG. For QCM-D, a rigid layer was formed for all the samples after rinsing. The layer thickness was 0.87 ± 0.20, 2.11 ± 0.31 and 2.63 ± 0.22 nm, and adsorbed mass was 87.17 ± 10.31, 210.56 ± 20.12 and 263.09 ± 23.23 ng cm^-2 , for HRG, lecithin and HRG/lecithin, respectively, indicating both HRG and lecithin were adsorbed at the oil-water interface. Structural rearrangements at the interface occurred for HRG/lecithin. The kinetics and final amount of lipid digestion depended on emulsifier type: lecithin > HRG/lecithin > HRG. These differences in digestion rate were primarily due to differences in the aggregation state of the emulsifiers.

CONCLUSION

The incorporation of lecithin into HRG emulsions had better interfacial properties comparing with HRG emulsion and facilitated lipid digestibility. These results provide important information for the rational design of plant-based functional food. © 2021 Society of Chemical Industry.

Medium and long-chain structured triacylglycerol enhances vitamin D bioavailability in an emulsion-based delivery system: combination of in vitro and in vivo studies

Vitamin D (VitD) is an essential fat-soluble micronutrient required for maintaining and regulating calcium homeostasis. Although sunlight can provide VitD, epidemiological studies indicate that the occurrence of VitD deficiency and insufficiency is widespread. Lipids are required at all stages of VitD digestion and absorption. In this research two different medium and long-chain triacylglycerol structures, possessing identical fatty acid composition lipids, namely structured triacylglycerol (STG), and physical mixtures of medium/long-chain triacylglycerol (MCT/LCT), were selected. Our results demonstrated that STG had a significant VitD bioavailability compared to MCT/LCT. In terms of the lipid digestion and absorption, the extent of the higher free fatty acid released (69.42%, p < 0.05), extent of lipolysis (89.28%, p < 0.05), lipolysis rate (0.06 s^-1, p < 0.05), and the ratio of the long-chain fatty acid to medium-chain fatty acid of STG (4.8, p < 0.05), result in a higher capacity for accommodating VitD when forming mixed micelles (61.31%, p < 0.05). An in vivo animal study also demonstrated that STG significantly increases the delivery ability of VitD (18.75 ng mL^-1, p < 0.05). The findings of this work may have unique applications for designing novel interesterified lipids with an effective delivery capacity for fat-soluble nutrients.

Effect of hydrocolloids on physicochemical properties, stability, and digestibility of Pickering emulsions stabilized by nanofibrillated cellulose

In this study, the effect of hydrocolloids with different electrostatic characteristics, namely negatively charged xanthan gum (XG), positively charged chitosan (CH), and non-ionic guar gum (GG), on the physicochemical properties, stability, and lipid digestibility of 10% (w/w) soybean oil-in-water Pickering emulsions stabilized by nanofibrillated cellulose (NFC) was investigated. Addition of XG and CH to the NFC-stabilized emulsions significantly increased the oil droplet sizes and apparent viscosity at high shear rates as compared with the addition of GG. The XG added emulsion showed the lowest rate and extent of creaming, whereas the CH added emulsion gave the highest extent of creaming. The addition of XG and CH led to a more pronounced effect on in vitro lipid digestion, i.e. changes in droplet sizes, surface charges, microstructure, and free fatty acid (FFA) release, than the addition of GG. The XG added emulsion showed the lowest rate and extent of lipid digestion possibly due to the high viscosity of the aqueous phase, large oil droplet sizes, and interaction of XG and calcium, resulting in the reduction of lipase activity. The CH added emulsion exhibited the highest extent of lipid digestion possibly due to binding between CH and FFAs and move away from the droplet surfaces, thereby facilitating the lipase activity. In summary, it can be concluded that ionic hydrocolloids exerted more influence on NFC-stabilized Pickering emulsions than non-ionic ones. These results may facilitate the design of highly stable emulsion-based functional food products with added hydrocolloids to promote health and wellness.

Nanoemulsions for Enhancement of Curcumin Bioavailability and Their Safety Evaluation: Effect of Emulsifier Type

This work aimed at evaluating the effects of different emulsifiers on curcumin-loaded nanoemulsions’ behavior during digestion, its safety and absorption, to develop nanoemulsions that provide safety and improved curcumin functionality. Nanoemulsions (NEs) were produced using two bio-based (lecithin (LEC) and rhamnolipids (RHAM)) and one synthetic (Tween^®80 (TWE)) emulsifier at similar concentrations. Different NEs were subjected to in vitro digestion. The cytotoxicity and permeability tests were performed in Caco-2 cells. NE_TWE were stable during all phases of in vitro digestion, whereas NE_LEC and NE_RHAM were found to be unstable from the gastric phase. NE_TWE showed 100% of free fatty acids released, followed by NE_RHAM and NE_LEC. Curcumin’s bioaccessibility and stability increased in the following order: NE_LEC > NE_RHAM > NE_TWE. NE_LEC and NE_TWE did not show cytotoxic effects in any of the concentrations tested, while NE_RHAM presented high cytotoxicity in all concentrations tested. The apparent permeability coefficients were determined for NE_LEC and NE_TWE; however, the results were not statistically different. These results showed that the emulsifier used has a high impact on nanoemulsions’ behavior under the digestion process and on their cytotoxicity. This work contributed to the state-of-the-art’s progress on the development of safer curcumin delivery systems with improved functionality, particularly regarding the proper selection of ingredients to produce said systems.

Improving the bioavailability of oil-soluble vitamins by optimizing food matrix effects: A review

The potency of oil-soluble vitamins (vitamins A, D, E and K) in fortified foods can be improved by understanding how food matrices impact their bioavailability. In this review, the major food matrix effects influencing the bioavailability of oil-soluble vitamins are highlighted: oil content, oil composition, particle size, interfacial properties, and food additives. Droplet size and aggregation state in the human gut impact vitamin bioavailability by modulating lipid digestion, vitamin release, and vitamin solubilization. Vitamins in small isolated oil droplets typically have a higher bioavailability than those in large or aggregated ones. Emulsifiers, stabilizers, or texture modifiers can therefore affect bioavailability by influencing droplet size or aggregation. The dimensions of the hydrophobic domains in mixed micelles depends on lipid type: if the domains are too small, vitamin bioavailability is low. Overall, this review highlights the importance of carefully designing food matrices to improve vitamin bioavailability.

Current approaches in lipid-based nanocarriers for oral drug delivery

Lipid-based nanocarriers have gained much interest as carriers of drugs with poor oral bioavailability because of their remarkable advantages like low toxicity, affordable scale-up manufacture, strong biocompatibility or high drug loading efficiency. The potential of these nanocarriers lies in their ability to improve the gastrointestinal stability, solubility and permeability of their cargo drugs. However, achieving efficient oral drug delivery through lipid-based nanocarriers is a challenging task, since they encounter multiple physicochemical barriers along the gastrointestinal tract, e.g. the gastric acidic content, the intestinal mucus layer or the enzymatic degradation, that they must surmount to reach their target. These limitations may be turned into opportunities through a rational design of lipid-based nanocarriers. For that purpose, this review focuses on the main challenges of the oral route indicating the strategies undertaken for lipid-based nanocarriers in order to overcome them. Understanding their shortcomings and identifying their strengths will determine the future clinical success of lipid-based nanocarriers.

Advances in edible nanoemulsions: Digestion, bioavailability, and potential toxicity

The design, fabrication, and application of edible nanoemulsions for the encapsulation and delivery of bioactive agents has been a highly active research field over the past decade or so. In particular, they have been widely used for the encapsulation and delivery of hydrophobic bioactive substances, such as hydrophobic drugs, lipids, vitamins, and phytochemicals. A great deal of progress has been made in creating stable edible nanoemulsions that can increase the stability and efficacy of these bioactive agents. This article highlights some of the most important recent advances within this area, including increasing the water-dispersibility of bioactives, protecting bioactives from chemical degradation during storage, increasing the bioavailability of bioactives after ingestion, and targeting the release of bioactives within the gastrointestinal tract. Moreover, it highlights progress that is being made in creating plant-based edible nanoemulsions. Finally, the potential toxicity of edible nanoemulsions is considered.

Effect of temperature and pH on the encapsulation and release of β-carotene from octenylsuccinated oat β-glucan micelles

Effect and working mechanism of temperature and pH on encapsulation and release of β-carotene from octenylsuccinated-oat-β-glucan-micelles (OSβG-Ms) were investigated. The stability and solubility of β-carotene, and changes in surface hydrophilicity, core hydrophobicity, and size of β-carotene-loaded-OSβG-Ms were determined. When exposed to temperature (25-45 °C) and pH (4.5-8.5), β-carotene solubilization changed in parabolic manners. Size and absolute zeta-potential of β-carotene-loaded-OSβG-Ms decreased with temperature, while they gave parabolic changing patterns with pH. Those results were ascribed to their hydrophilicity, hydrophobicity, and core/shell compactness via regulating molecule mobility, orientation, and interactions by temperature/pH. The higher temperature concluded with higher β-carotene release, while a U-shaped release profile was observed with pH. Besides its diffusion, erosion-induced shrinking and collapsing of OSβG-Ms favored β-carotene release at pH 1.2-4.5, which was replaced by swelling-induced structural-relaxation at pH 6.8-8.5. The results were favourable in controlling the behavior of β-carotene-loaded-OSβG-Ms by selectively applying environmental parameters.

Improving the In Vitro Bioaccessibility of β-Carotene Using Pectin Added Nanoemulsions

The intestinal absorption of lipophilic compounds such as β-carotene has been reported to increase when they are incorporated in emulsion-based delivery systems. Moreover, the reduction of emulsions particle size and the addition of biopolymers in the systems seems to play an important role in the emulsion properties but also in their behavior under gastrointestinal conditions and the absorption of the encapsulated compound in the intestine. Hence, the present study aimed to evaluate the effect of pectin addition (0%, 1%, and 2%) on the physicochemical stability of oil-in-water nanoemulsions containing β-carotene during 35 days at 4 °C, the oil digestibility and the compound bioaccessibility. The results showed that nanoemulsions presented greater stability and lower β-carotene degradation over time in comparison with coarse emulsion, which was further reduced with the addition of pectin. Moreover, nanoemulsions presented a faster digestibility irrespective of the pectin concentration used and a higher β-carotene bioaccessibility as the pectin concentration increased, being the maximum of ≈36% in nanoemulsion with 2% of pectin. These results highlight the potential of adding pectin to β-carotene nanoemulsions to enhance their functionality by efficiently preventing the compound degradation and increasing the in vitro bioaccessibility.

Nanostructured Lipid-Based Delivery Systems as a Strategy to Increase Functionality of Bioactive Compounds

Acquisition of a healthy lifestyle through diet has driven the food manufacturing industry to produce new food products with high nutritional quality. In this sense, consumption of bioactive compounds has been associated with a decreased risk of suffering chronic diseases. Nonetheless, due to their low solubility in aqueous matrices, high instability in food products during processing and preparation as well as poor bioavailability, the use of such compounds is sometimes limited. Recent advancements in encapsulation and protection of bioactive compounds has opened new possibilities for the development of novel food products. In this direction, the present review is attempting to describe encapsulation achievements, with special attention to nanostructured lipid-based delivery systems, i.e., nanoemulsions, multi-layer emulsions and liposomes. Functionality of bioactive compounds is directly associated with their bioavailability, which in turn is governed by several complex processes, including the passage through the gastrointestinal tract and transport to epithelial cells. Therefore, an overview of recent research on the properties of these nanostructured lipid-based delivery systems with a strong impact on the functionality of bioactive compounds will be also provided. Nanostructured lipid-based delivery systems might be used as a potential option to enhance the solubility, stability, absorption and, ultimately, functionality of bioactive compounds. Several studies have been performed in this line, modifying the composition of the nanostructures, such as the lipid-type or surfactants. Overall, influencing factors and strategies to improve the efficacy of encapsulated bioactive compounds within nanostructures have been successfully identified. This knowledge can be used to design effective targeted nanostructured lipid-based delivery systems for bioactive compounds. However, there is still a lack of information on food interactions, toxicity and long-term consumption of such nanostructures.

Factors impacting lipid digestion and β-carotene bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): oil droplet concentration

The impact of oil droplet concentration on lipid digestion and vitamin bioaccessibility was measured using the INFOGEST method.