Encapsulation of Lutein via Microfluidic Technology: Evaluation of Stability and In Vitro Bioaccessibility

Carotenoid Bioaccessibility and Caco-2 Cell Uptake Following Novel Encapsulation Using Medium Chain Triglycerides

Carotenoids are especially hydrophobic and dissolve poorly in water. Encapsulation is used to increase their solubility in water-based food products. However, it is not yet known whether encapsulation with a combination of lecithin and medium-chain triglycerides improves carotenoid bioaccessibility and intestinal cell uptake. The relative bioaccessibility and Caco-2 cell uptake of two water-soluble carotenoid (i.e. lutein and astaxanthin) dispersions in a liquid form (VitaSperse®) and a powdered form (VitaDry®) were compared to the carotenoid ingredient alone. An in vitro digestion model was used to assess bioaccessibility, measuring the micellarized fraction postdigestion. The micelle fraction was incubated with Caco-2 cells to assess intestinal uptake of carotenoids. Encapsulation (by either VitaDry® or Vitasperse®) increased total astaxanthin bioaccessibility 2-2.4× and cell uptake by ∼2× relative to control. Encapsulation also increased total lutein bioaccessibility by 3-5× and cell uptake 2.3× relative to control. There was no significant difference between VitaDry® and VitaSperse® products in regards to Caco-2 cell uptake. Increased bioaccessibility largely drove increased carotenoid cell uptake from the encapsulated formulations. These results suggest further study is warranted to determine if this encapsulation approach increases carotenoid bioavailability in human studies.

Preparation and Characterization of Lutein Co-Amorphous Formulation with Enhanced Solubility and Dissolution

Lutein is an oxygenated fat-soluble carotenoid and a functional compound with proven health benefits for the human body. Nevertheless, the poor water solubility and low oral bioavailability of lutein greatly limit its application. To address this, we developed an effective approach to enhance the water solubility of lutein through co-amorphous formulation. Specifically, the lutein-sucralose co-amorphous mixture was prepared at a molar ratio of 1:1 using ethanol and water as solvents by employing the solvent evaporation method, followed by solid-state characterization and dissolution testing conducted to assess the properties of the formulation. The X-ray diffraction pattern with an amorphous halo and the differential scanning calorimetry thermogram with no sharp melting peaks confirmed the formation of a binary co-amorphous system. Changes in peak shape, position, and intensity observed in the Fourier transform infrared spectroscopy spectrum revealed intermolecular interactions between lutein and sucralose molecules, while molecular dynamics simulations identified interaction sites between their hydroxyl groups. Additionally, dissolution testing demonstrated better dissolution performance of lutein in the co-amorphous form compared to pure lutein and physical mixture counterparts. Our findings present a novel strategy for improving the water solubility of lutein to make better use of it.

Lutein encapsulation into dual-layered starch/zein gels using 3D food printing: Improved storage stability and in vitro bioaccessibility

The ability of 3D printing to encapsulate, protect, and enhance lutein bioaccessibility was investigated under various printing conditions. A spiral-cube-shaped geometry was used to investigate the effects of printing parameters, namely zein concentration (Z; 20, 40, and 60 %) and printing speed (PS; 4, 8, 14, and 20 mm/s). Coaxial extrusion 3D printing was used with lutein-loaded zein as the internal flow material, and corn starch paste as the external flow material. The viscosities of the inks, microstructural properties, storage stability, and bioaccessibility of encapsulated lutein were determined. The sample printed with a zein concentration of 40 % at a printing speed of 14 mm/s (Z-40/PS-14) exhibited the best shape integrity. When lutein was entrapped in starch/zein gels (Z-40/PS-14), only 39 % of lutein degraded after 21 days at 25 °C, whereas 78 % degraded at the same time when crude lutein was studied. Similar improvements were also observed after storing at 50 °C for 21 days. Furthermore, after simulated digestion, the bioaccessibility of encapsulated lutein (9.8 %) was substantially higher than that of crude lutein (1.5 %). As a result, the developed delivery system using 3D printing could be an effective strategy for enhancing the chemical stability and bioaccessibility of bioactive compounds (BCs).

Developing biopolymer-stabilized emulsions for improved stability and bioaccessibility of lutein

Lutein is essential for infant visual and cognitive development but has low stability and solubility. This study aimed to enhance the stability and bioaccessibility of lutein using oil-in-water emulsions stabilized with biopolymers. Commercially available octenylsuccinylated (OS) starches, including capsule TA® (CTA), HI-CAP®100 (HC), and Purity Gum® 2000 (PG), along with gum Arabic (GA) variants Ticaloid acacia Max® (TAM), TICAmulsion® 3020 (TM), and pre-hydrate gum Arabic (PHGA), were chosen as emulsifiers. By screening the effect of biopolymer concentration and oil volume fraction (Φ), emulsions stabilized with CTA, HC, or TM at 20% and 30% (w/v) concentration and 70% Φ exhibited a gel-like structure and were selected for further assessments. After a week at 25 °C, emulsions stabilized by CTA and HC showed no significant change in droplet size, while TM emulsion exhibited a 1.58-fold increase. At 45 °C, all emulsions exhibited increase in droplet size. Lutein retention is higher in CTA emulsions at both storage temperatures than free lutein. In vitro bioaccessibility of all lutein emulsions was higher than that of free lutein. These findings highlight the superior stability and bioaccessibility of the lutein emulsion stabilized by OS starch, positioning it as a promising carrier to broaden lutein applications in infant foods.

Enhancing Anticancer Efficacy of Formononetin Microspheres via Microfluidic Fabrication

Formononetin is a flavonoid compound with anti-tumor and anti-inflammatory properties. However, its low solubility limits its clinical use. We employed microfluidic technology to prepare formononetin-loaded PLGA-PEGDA microspheres (Degradable polymer PLGA, Crosslinking agent PEGDA), which can encapsulate and release drugs in a controlled manner. We optimized and characterized the microspheres, and evaluated their antitumor effects. The microspheres had uniform size, high drug loading efficiency, high encapsulation efficiency, and stable release for 35 days. They also inhibited the proliferation, migration, and apoptosis. The antitumor mechanism involved the induction of reactive oxygen species and modulation of Bcl-2 family proteins. These findings suggested that formononetin-loaded PLGA-PEGDA microspheres, created using microfluidic technology, could be a novel drug delivery system that can overcome the limitations of formononetin and enhance its antitumor activity.

Oral bioavailability of bioactive compounds; modulating factors, in vitro analysis methods, and enhancing strategies

Foods are complex biosystems made up of a wide variety of compounds. Some of them, such as nutrients and bioactive compounds (bioactives), contribute to supporting body functions and bring important health benefits; others, such as food additives, are involved in processing techniques and contribute to improving sensory attributes and ensuring food safety. Also, there are antinutrients in foods that affect food bioefficiency and contaminants that increase the risk of toxicity. The bioefficiency of food is evaluated with bioavailability which represents the amount of nutrients or bioactives from the consumed food reaching the organs and tissues where they exert their biological activity. Oral bioavailability is the result of some physicochemical and biological processes in which food is involved such as liberation, absorption, distribution, metabolism, and elimination (LADME). In this paper, a general presentation of the factors influencing oral bioavailability of nutrients and bioactives as well as the in vitro techniques for evaluating bioaccessibility and is provided. In this context, a critical analysis of the effects of physiological factors related to the characteristics of the gastrointestinal tract (GIT) on oral bioavailability is discussed, such as pH, chemical composition, volumes of gastrointestinal (GI) fluids, transit time, enzymatic activity, mechanical processes, and so on, and the pharmacokinetics factors including BAC and solubility of bioactives, their transport across the cell membrane, their biodistribution and metabolism. The impact of matrix and food processing on the BAC of bioactives is also explained. The researchers' recent concerns for improving oral bioavailability of nutrients and food bioactives using both traditional techniques, for example, thermal treatments, mechanical processes, soaking, germination and fermentation, as well as food nanotechnologies, such as loading of bioactives in different colloidal delivery systems (CDSs), is also highlighted.

Effects of dietary fat type and emulsification on carotenoid absorption: a randomized crossover trial

BACKGROUND

Although emerging evidence has suggested that the type and emulsification of dietary fat may be important to carotenoids absorption, these effects have not yet been validated in a human trial.

OBJECTIVE

This study aimed to examine the effects of dietary fat type and emulsification on the bioaccessibility and bioavailability of carotenoids from a carotenoids-rich salad.

METHODS

An identical salad was used for the in vitro and the human trial. This was paired with 28 g of one of the following four different fats: i) non-emulsified olive oil; ii) emulsified olive oil; (iv) non-emulsified coconut oil; v) emulsified coconut oil. The bioaccessibility of total carotenoids (TC) was assessed by a simulated in vitro digestion model. Sixteen subjects consumed salad with four test fats in random order, and plasma triglyceride and carotenoid (lutein, zeaxanthin, α-carotene, β-carotene, and lycopene) concentrations were determined hourly for 10 hours following the consumption. The absorption of TC and individual carotenoids were evaluated by the positive incremental area under the curve (iAUC) of plasma carotenoid concentrations.

RESULTS

The bioaccessibility of TC was greater with olive oil (24.0%) than with coconut oil (14.9%), and with the oil being emulsified (23.5%) rather than non-emulsified (15.4%). Likewise, the positive iAUC_1-10h of TC, α-carotene and lycopene were 55.2%, 110.8% and 45.8%, respectively, higher with olive oil than with coconut oil. Emulsified fat induced 40.0% greater positive iAUC_1-10h of TC than non-emulsified fat.

CONCLUSIONS

The type and emulsification of dietary fat are both essential to the carotenoid absorption. Findings from this study may provide scientific support for designing excipient emulsions as potential dietary strategies to optimize the absorption of fat-soluble compounds.

CLINICAL TRIAL REGISTRY

The present trial was registered at clinicaltrials.gov (NCT04323826), link: https://clinicaltrials.gov/ct2/show/NCT04323826.

Nanoscale Delivery Systems of Lutein: An Updated Review from a Pharmaceutical Perspective

Carotenoids are natural lipid-soluble pigments that produce yellow to red colors in plants as well as providing bright coloration in vegetables and fruits. Lutein belongs to the xanthophyll subgroup of the carotenoid family, which plays an essential role in photosynthesis and photoprotection in nature. In the human body, lutein, together with its isomer zeaxanthin and its metabolite meso-zeaxanthin, accumulates in the macula of the eye retina, which is responsible for central, high-resolution, and color vision. As a bioactive phytochemical, lutein has essential physiological functions, providing photoprotection against damaging blue light, along with the neutralization of oxidants and the preservation of the structural and functional integrity of cellular membranes. As a potent antioxidant and anti-inflammatory agent, lutein unfortunately has a low bioavailability because of its lipophilicity and a low stability as a result of its conjugated double bonds. In order to enhance lutein stability and bioavailability and achieve its controlled delivery to a target, nanoscale delivery systems, which have great potential for the delivery of bioactive compounds, are starting to be employed. The current review highlights the advantages and innovations associated with incorporating lutein within promising nanoscale delivery systems, such as liposomes, nanoemulsions, polymer nanoparticles, and polymer–lipid hybrid nanoparticles, as well as their unique physiochemical properties.