Bioaccessibility Of Curcumin Research Articles

One-step self-assembly of curcumin-loaded zein/sophorolipid nanoparticles: physicochemical stability, redispersibility, solubility and bioaccessibility.

Curcumin, a polyphenolic compound isolated from turmeric, exhibits various biological activities. The application of this nutraceutical in foods, however, is limited due to its extreme hydrophobicity, inferior stability, and poor bioaccessibility. The purpose of this paper is to prepare alcohol-free curcumin-loaded zein/sophorolipid nanoparticles (Cur-Z/SNPs) by one-step self-assembly to overcome the abovementioned challenges of curcumin. In detail, Cur-Z/SNPs were formed by mixing curcumin, zein, and sophorolipid under neutral conditions without any organic reagents or high energy equipment. The encapsulation efficiency and loading capacity of Cur-Z/SNPs were 94.08% and 11.50%, respectively. The spherical shape of Cur-Z/SNPs was observed by using a transmission electron microscope. The self-assembly mechanism involved hydrogen bonding, hydrophobic and electrostatic interactions, and the crystalline nature of curcumin changed to amorphous during self-assembly. Cur-Z/SNPs enhanced the zein denaturation resistance. They exhibited complete redispersibility and improved the aqueous solubility by approximately 246 times compared with free curcumin. The fresh Cur-Z/SNPs exhibited physicochemical stability at pH 5.0-8.0, ionic strength within 250 mM, and storage at 25 °C and 4 °C for 30 days. Notably, Cur-Z/SNPs could achieve excellent storage stability at room temperature as compared to those at refrigeration. Furthermore, lyophilization had a positive effect on storage stability, did not change the pH stability, and slightly reduced the ionic strength stability. Besides, Cur-Z/SNPs increased the 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH˙) scavenging capacity compared to free curcumin. The bioaccessibility of curcumin was increased by about 6 times by Cur-Z/SNPs. These findings provided new insight into the application of hydrophobic nutrients in alcohol-free functional foods.

In-vitro stress stability, digestibility and bioaccessibility of curcumin-loaded polymeric nanocapsules

Nanoemulsion-based delivery systems have a considerable potential for the encapsulation, protection and delivery of lipophilic bioactives. In the current study, in-vitro stability of curcumin-loaded single (NEI), double (NEII), and triple-layered nanostructures was investigated against varying environmental stress (temperature, pH, ionic strength) and storage conditions. In addition, their functional performance, as influenced by the number of polymer layers, was also assessed by comparing in-vitro lipid digestibility and curcumin bioaccessibility. Initially, NEI was prepared through ultrasonic homogenisation technique, and stabilised with modified starch. Next, sequential deposition of chitosan and carboxymethyl cellulose (CMC) on the NEI droplets resulted into the formation of NEII and nanocapsules, respectively. Nanocapsules showed good stability against aggregation over a wide range of pH (3.0–7.0), salt concentration (50–300 mM NaCl) and temperature (30–90 °C for 30 min). Digestion studies suggested that polymeric coatings interfered with lipolysis as the digestibility (% free fatty acid released) of oil droplets was considerably reduced with increasing the number of layers surrounding the oil droplets. However, curcumin bioaccessibility increased with adding the number of coating layers. Overall, results indicate that the developed nano-system could be helpful in improving the oral delivery of curcumin besides incorporating it into functional foods and beverages.

Effects of the degree of substitution of OSA on the properties of starch microparticle-stabilized emulsions

An amphiphilic polymer of octenyl succinic anhydride (OSA)-modified starch microparticles (SMPs) was synthesized and used to stabilize emulsions. The effects of the degree of substitution (DS) on the physicochemical properties of OSA-modified SMPs and the stability of OSA-modified SMP-stabilized emulsions during a three-step in vitro digestion model were studied. The results showed that OSA esterification acted on the surface of SMPs and that the hydrophobicity of SMPs improved with increasing DS. In addition, the emulsion stability during storage and the changes in ionic strength were enhanced by increasing DS. Moreover, a higher DS also led to smaller oil droplets and more OSA-modified SMPs retained during intestinal digestion. Most importantly, the encapsulation efficiency and the bioaccessibility of curcumin in the emulsion during intestinal digestion were both enhanced significantly with the increase of DS.

Impact of microfluidization and thermal treatment on the structure, stability and in vitro digestion of curcumin loaded zein-propylene glycol alginate complex nanoparticles

The aim of this study was to modulate the physicochemical properties, molecular interactions and microstructure of zein-propylene glycol alginate (PGA) complex nanoparticles for delivery of curcumin with the aid of high pressure microfluidization (HPM) (50–150 MPa) and thermal treatment (45–85 °C). The size of zein-PGA complex nanoparticles was decreased to around 300 nm. It was confirmed that the pressure of 100 MPa and temperature of 75 °C were the optimum parameters to provide a better protection of entrapped curcumin against environmental stresses. The electrostatic interaction, hydrogen bonding and hydrophobic attraction were the dominant driving forces in the formation of the complex nanoparticles. Field emission scanning electron microscopy (FE-SEM) revealed that HPM and thermal treatment facilitated the complex nanoparticles to form a more uniform size and spherical shape. During in vitro gastrointestinal digestion, zein-PGA complex nanoparticles showed excellent gastric stability and sustained-release of curcumin in the small intestine. HPM and thermal treatment showed a synergistic effect on enhancing the bioaccessibility of curcumin entrapped in zein-PGA complex nanoparticles. The findings revealed the influence of HPM and thermal treatment on functional attributes of the complex nanoparticles, which could be utilized to design food grade nanoparticles with desirable stability and digestive properties.

An efficient small intestine-targeted curcumin delivery system based on the positive-negative-negative colloidal interactions

In order to decrease the transformation and increase the bioaccessibility of curcumin through an emulsion-based delivery system, two main characteristics should be considered: first, to keep curcumin in the oil droplets during the gastric phase; second, to release curcumin efficiently in the small intestine. However, commonly-used delivery systems lack at least one of these two key characteristics. Using an INFOGEST static in vitro simulation model, this study aimed to investigate the ability of a positive-negative-negative (PNN) delivery system to protect curcumin against the gastric phase and release it in the small intestine. The results showed the PNN system was more resistant against gastric proteolysis, compared with a primary emulsion and two bilayer emulsions. The high-pressure liquid chromatography results showed that only 5% of the initial curcumin in the PNN system was released at the end of the gastric phase (versus >55% for the other three systems). In contrast, during the simulated small intestine, the remaining content of the protein in the PNN system was readily digested and released curcumin. Almost 84% of the initial curcumin in the PNN system was released efficiently in the small intestine, compared with less than 20% release for other delivery systems. The initial rate and final amount of the free fatty acids released from the PNN system were also at least 20% higher than that of other systems. Therefore, the PNN is an efficient system for gastric protection and targeted delivery/release of curcumin in the small intestine.

Complexation of curcumin using proteins to enhance aqueous solubility and bioaccessibility: Pea protein vis-à-vis whey protein

Abstract Curcumin faces challenges such as poor aqueous solubility and limited bioaccessibility which limits its oral therapeutic applications. This work evaluated the complexation of curcumin using pea protein isolate (PPI, leguminous protein) vis-a-vis whey protein isolate (WPI, animal protein) to overcome these limitations. Thermodynamic parameters (ΔH and ΔS) indicated the interaction to be hydrophobic in nature. While WPI-curcumin complex showed better aqueous solubility for curcumin than PPI-curcumin complex at varying pH (3, 5 & 7), the PPI-curcumin complex showed better solubility at higher temperature of 80 °C. The solubility of curcumin in WPI-curcumin and PPI-curcumin complex at pH 7 was 1.16 mg/g and 1.02 mg/g, respectively. The protein curcumin solutions were further spray dried and characterized for surface hydrophobicity, crystallinity, thermal properties, and surface morphology. Both the proteins showed a similar score for bioaccessibility of curcumin from their respective complexes. Thus PPI can be a good non-dairy protein alternative for curcumin delivery.

Characterization of ethanol-induced egg white gel and transportation of active nutraceuticals

This paper investigated the gelling characteristics of ethanol-induced egg white gel (EEWG) and also evaluated the ability of EEWG to delivery curcumin and tea polyphenols (TP). Results showed that a high concentration of ethanol induced egg white (EW) to form gel, which was attributed to the increase of zeta potential in absolute value and free sulfhydryl content. A high concentration of ethanol reduced the intrinsic fluorescence, mainly of tryptophan, and increased the viscosity. EEWG with a high concentration of protein represented greater hardness and water-holding capacity combined with the formation of abundant small bubbles. The addition of TP decreased the hardness value and water-holding capacity and reduced the storage modulus and loss modulus, determined by a rheometer, for further prevention of EW protein denaturation. The curcumin and TP stabilities were improved after adding a higher concentration of protein during storage. Adding a proper concentration of ethanol (30–40 mL/100 mL) increased the bioaccessibility of curcumin and improved the antioxidant activity and protein digestibility, but this was decreased after EEWG was loaded with TP. These results suggested that EW protein could improve the delivery of a hydrophobic active substance.

Pickering emulsions stabilized by colloidal gel particles complexed or conjugated with biopolymers to enhance bioaccessibility and cellular uptake of curcumin

The aim of this study was to investigate the fate of curcumin (CUR)-loaded Pickering emulsions with complex interfaces during in vitro gastrointestinal transit and test the efficacy of such emulsions on improving the bioaccessibility and cellular uptake of CUR. CUR-loaded Pickering emulsions tested were whey protein nanogel particle-stabilized Pickering emulsions (CUR-EWPN) and emulsions displaying complex interfaces included 1) layer-by-layer dextran sulphate-coated nanogel-stabilized Pickering emulsions (CUR-DxS+EWPN) and 2) protein+dextran-conjugated microgel-stabilized Pickering emulsions (CUR-EWPDxM). The hypothesis was that the presence of complex interfacial material at the droplet surface would provide better protection to the droplets against physiological degradation, particularly under gastric conditions and thus, improve the delivery of CUR to Caco-2 intestinal cells. The emulsions were characterized using droplet sizing, apparent viscosity, confocal and cryo-scanning electron microscopy, zeta-potential, lipid digestion kinetics, bioaccessibility of CUR as well as cell viability and uptake by Caco-2 cells. Emulsion droplets with modified to complex interfacial composition (i.e. CUR-DxS+EWPN and CUR-EWPDxM) provided enhanced kinetic stability to the Pickering emulsion droplets against coalescence in the gastric regime as compared to droplets having unmodified interface (i.e. CUR-EWPN), whereas droplet coalescence occurred in intestinal conditions irrespective of the initial interfacial materials. A similar rate and extent of free fatty acid release occurred in all the emulsions during intestinal digestion (p > 0.05), which correlated with the bioaccessibility of CUR. Striking, CUR-DxS+EWPN and CUR-EWPDxM significantly improved cellular CUR uptake as compared to CUR-EWPN (p < 0.05). These results highlight a promising new strategy of designing gastric-stable Pickering emulsions with complex interfaces to improve the delivery of lipophilic bioactive compounds to the cells for the future design of functional foods.

High dispersity, stability and bioaccessibility of curcumin by assembling with deamidated zein peptide

Many liposoluble nutrients are restricted for applications in foods due to their poor water solubility, stability and bioavailability. Here, a deamidated zein peptide with a broad molecular weight distribution and high carboxyl and hydrophobic residue contents was used to solubilize curcumin. The complex nanoparticles of curcumin and the peptide were produced through self-assembly in aqueous solutions. Fluorescence and infrared spectra revealed that hydrogen bonding and hydrophobic interactions actuated the assembly. The complex nanoparticles had a curcumin loading capacity of 31.9% and completely inhibited curcumin crystallization. The peptide effectively protected curcumin from decomposition in aqueous solutions by inhibiting the reaction between dissolved oxygen and curcumin. The nanoparticles presented excellent freeze-drying/re-dispersion stability without any lyoprotectant. The curcumin bioaccessibility of the nanoparticles was 75% and the nanoparticles exerted a significant antioxidant effect after oral administration in mice. This study indicates that the nanoparticles are potentially useful as an antioxidant additive in foods.

Spray-drying microencapsulation of curcumin nanocomplexes with soy protein isolate: Encapsulation, water dispersion, bioaccessibility and bioactivities of curcumin

The spray-drying microencapsulation of curcumin encapsulated in soy protein isolate (SPI) nanocomplexes, as well as the influence of spray-drying on encapsulation, water redispersion behavior, bioaccessibility, and bioactivities (antioxidant and anti-cancer) of encapsulated curcumin, was investigated. The addition of soy soluble polysaccharide (SSPS) and/or maltodextrin (MD), alone or in a combination, prior to the spray-drying, greatly improved the microencapsulation performance of the nanocomplex, and water dispersion behavior of the corresponding spray-dried powders. Regardless of the addition of SSPS or MD, the spray-drying remarkably decreased the bioaccessibility of encapsulated curcumin, which seemed to be associated with the aggregation of the nanocomplexes. The curcumin encapsulated in the spray-dried nanocomplex exhibited a much higher oxygen radical absorbance capacity than free curcumin (in DMSO). Both free and encapsulated curcumin showed a remarkable cytotoxicity or anti-proliferation against human hepatal carcinoma HepG2 cells, but the effects were highly dose-dependent. In the cytotoxicity evaluation, at high curcumin concentrations, e.g., 40–80 μM, encapsulated curcumin induced apoptosis of the cells, to a significantly less extent, than free curcumin. However, in the anti-proliferation case, at low concentrations (e.g., <30 μM) the encapsulated curcumin exhibited a more effective inhibition of cell proliferation than free curcumin. At high concentrations (>30 μM), both free and encapsulated curcumin inhibited the cell proliferation via the arrest of cells in G2/M phase, while at low curcumin concentrations, the antioxidant activity might largely account for the inhibition effects. The findings would be of importance for the use of soy protein nanocarriers for encapsulation and delivery of poorly soluble bioactives, in the functional food formulations.

The influence of oil composition on the transformation, bioaccessibility, and intestinal absorption of curcumin in nanostructured lipid carriers.

In this study, the influences of liquid medium-chain triglyceride (MCT) and solid glyceryl tristearate (GTS) contents in the lipid matrix of nanostructured lipid carriers (NLCs) on their delivering capacities with respect to curcumin (Cur) were investigated by using a simulated gastrointestinal tract and Caco-2 monolayer models. The transformation of the encapsulated Cur decreased on increasing the MCT content in the lipid matrix of NLCs because it facilitated their lipolysis and promoted the exposure of Cur to a harsher exterior environment. Cur bioaccessibility was positively correlated with the level of micellized stearic acid resulting from GTS hydrolysis, which might be attributed to the fact that it could afford large hydrophobic domains to accommodate Cur. This value initially increased with an increase in the MCT content, reaching a maximum at 20% (w/w) and decreasing thereafter. The intestinal absorption of micellar Cur ranged from 26.06% to 38.76%, and a majority of the transported molecules were its reductive and conjugative metabolites. Overall, NLC containing 20% MCT in the lipid matrix afforded the highest Cur bioavailability, followed by that containing 10, 0, 40, 60, and 100% MCT. This work provides useful insights into the rational design of NLCs to optimize the bioavailability of the loaded agent.

Exploration of the Stabilization Mechanism and Curcumin Bioaccessibility of Emulsions Stabilized by Whey Protein Hydrolysates after Succinylation and Glycation in Different Orders.

The combined effects of succinic anhydride (SA) succinylation and linear dextrin (LD) glycation on whey protein hydrolysates (WPH) and their stabilized emulsions were evaluated. Degree of succinylation (DS), degree of glycation (DG), and degree of browning of samples suggested that a competitive displacement of reactive groups existed when WPH reacted with SA and LD in different orders. Attenuated total reflection Fourier transform infrared (ATR-FTIR) and far-UV circular dichroism (CD) indicated that the order of modification methods had a significant effect on secondary structures of WPH. Succinylation combined with glycation effectively reduced the surface hydrophobicity and increased the molecular flexibility of WPH. Meanwhile, the total free -SH content decreased, and the exposed free -SH content increased. Results of storage stability and gastrointestinal fate of the curcumin-loaded emulsion revealed that the modified WPH with higher DS was more effective for improving the curcumin bioaccessibility, while that with higher DG was more effective for enhancing the stability of the emulsion.

A novel and green nanoparticle formation approach to forming low-crystallinity curcumin nanoparticles to improve curcumin\u2019s bioaccessibility

Health-promoting effects of curcumin are well-known; however, curcumin has a very low bioavailability due to its crystalline structure. The main objective of this study was to develop a novel green nanoparticle formation method to generate low-crystallinity curcumin nanoparticles to enhance the bioavailability of curcumin. Nanoporous starch aerogels (NSAs) (surface area of 60 m2/g, pore size of 20 nm, density of 0.11 g/cm3, and porosity of 93%) were employed as a mold to produce curcumin nanoparticles with the help of supercritical carbon dioxide (SC-CO2). The average particle size of the curcumin nanoparticles was 66 nm. Impregnation into NSAs decreased the crystallinity of curcumin and did not create any chemical bonding between curcumin nanoparticles and the NSA matrix. The highest impregnation capacity was 224.2 mg curcumin/g NSA. Curcumin nanoparticles significantly enhanced the bioaccessibility of curcumin by 173-fold when compared to the original curcumin. The concentration of curcumin in the bioaccessible fraction was improved from 0.003 to 0.125 mg/mL by impregnation of curcumin into NSAs (42-fold). This is a novel approach to produce food grade curcumin nanoparticles with reduced crystallinity and maximize the utilization of curcumin due to increased bioaccessibility.

Fabrication and characterization of zein nanoparticles by dextran sulfate coating as vehicles for delivery of curcumin

Zein nanoparticles (ZNPs) have limited use as a result of its poor colloidal stability. The goal of this paper is to stabilize ZNPs using a sulfated anionic polysaccharide—dextran sulfate (DS). Zein/DS composite nanoparticles (ZDSNPs) were fabricated by antisolvent precipitation method at pH 4.0 with an optimal zein-to-DS ratio of 1:2 (w/w). ZDSNPs exhibited good stability to pH, heating and storage. Additionally, ZDSNPs showed spherical structures formed primarily by electrostatic attractions, hydrogen bonding and hydrophobic interactions. The incorporation of DS led to the change in secondary structure of zein. The surface hydrophobicity of ZNPs reduced owing to the deposition of DS. And ZDSNPs were basically nontoxic to normal colonic epithelial cell lines—NCM460 cell lines. ZDSNPs were successfully used to encapsulate curcumin. The encapsulation efficiency of curcumin-loaded ZDSNPs (ZDSCNPs) was 85.37%, which was significantly higher than that of curcumin-loaded ZNPs. In addition, ZDSCNPs exhibited improved storage stability and bioaccessibility of curcumin.

Pickering emulsions stabilized by amphiphilic anisotropic nanofibrils of glycated whey proteins

Anisotropic protein nanofibrils may be fabricated with unique interfacial properties by glycating proteins with saccharides. In this study, nanofibrils were produced from whey protein isolate (WPI) glycated with glucose, lactose, or maltodextrin by heating at pH 2.0 and 90 °C, and the properties of nanofibrils forming and stabilizing Pickering O/W emulsions were studied. Glycation reduced fibril length but not width based on atomic force and transmission electron microscopy. Nanofibrils derived from glycated WPI had the increased hydrophobicity and formed a thick layer on oil droplets that were more stable during prolonged storage at room temperature and at pH 2.0–8.0, 0–250 mM NaCl than emulsions prepared with WPI nanofibrils. The carbohydrate chain length positively impacted the emulsion viscosity while negatively impacted lipolysis and bioaccessibility of curcumin encapsulated in emulsions. These findings suggest unique properties of nanofibrils based on glycated proteins for preparation of emulsions with controllable digestion and release properties.

Bioaccessibility of curcumin encapsulated in yeast cells and yeast cell wall particles

This study evaluates the role of intracellular composition and integrity of cell walls in modulating the release and bioaccessibility of phytochemicals during simulated gastrointestinal digestion of cell-based carriers. Native yeast and yeast cell wall particles (YCWPs) were used as model cell-based carriers with distinct intracellular composition and curcumin was a model encapsulated bioactive. The results highlight the essential role of gastric treatments and the presence of bile salts in the release and bioaccessibility of encapsulated compound from cell-based carriers. YCWPs with significantly reduced intracellular contents have a significantly faster intestinal release after gastric digestion. Multimodal imaging approaches confirm the release of encapsulated curcumin in intestinal compartment without any significant changes in the cellular structure including cell walls. Based on these results, the study proposes a model that illustrate the significance of gastric digestion in influencing the release of curcumin during gastrointestinal digestion.

Fabrication of Curcumin-Loaded Dairy Milks Using the pH-Shift Method: Formation, Stability, and Bioaccessibility.

The pH-shift method is a simple approach for incorporating certain kinds of polyphenol-based nutraceuticals into already existing colloidal systems. The polyphenols can be loaded into hydrophobic particles due to the fact that their water-solubility is relatively high under alkaline conditions but low under acid or neutral conditions. In this study, it was demonstrated that bovine milk could be enriched with curcumin using this approach, without adversely affecting milk fat globule stability. The storage stability of the curcumin-enriched bovine milk was assessed when samples were incubated for 60 days at different pH values and temperatures. The pH-stability was determined by storing curcumin-enriched milk at 4 °C for 60 days at pH 6.5, 7.0, and/or 8.0. At this low storage temperature, all milk samples were stable to fat globule aggregation, creaming, curcumin degradation (<13% loss), and color loss. The temperature-stability was determined by storing curcumin-enriched milk at pH 7 for 15 days at 4, 20, 37, or 55 °C. Curcumin breakdown decreased with decreasing storage temperature: 55 °C (43%) > 37 °C (21%) > 20 °C (10%) > 4 °C (5%). Interestingly, the color of the curcumin-enriched milks incubated at 4, 20, and 37 °C remained similar to that of the initial samples, but the sample stored at 55 °C showed significant color fading. Curcumin bioaccessibility determined using an in vitro gastrointestinal tract was around 40%, which was attributed to some chemical degradation and binding of the curcumin reducing its stability and solubilization. This study shows that a hydrophobic nutraceutical (curcumin) can be loaded into dairy milk products using a simple method, which could facilitate the creation of novel functional foods and beverages.

Co-encapsulation of Epigallocatechin Gallate (EGCG) and Curcumin by Two Proteins-Based Nanoparticles: Role of EGCG.

In this study, a novel plant-protein-based nanoparticle delivery system was developed to encapsulate and stabilize curcumin and epigallocatechin gallate (EGCG) with different polarities. The strongly hydrophobic curcumin was embedded within the hydrophobic cores of zein nanoparticles using an antisolvent method, while the weakly hydrophobic EGCG was adsorbed to the region between the zein core and caseinate shell. The physicochemical properties, structure, and stability of the core-shell particles were characterized using dynamic light scattering, particle electrophoresis, fluorescence spectroscopy, and Fourier transform infrared spectroscopy. The bioaccessibility of curcumin in the core-shell nanoparticles was determined using a simulated gastrointestinal tract. Mean particle diameters around 100-200 nm could be produced by modulating the mass ratio of curcumin to zein. The encapsulation efficiency of curcumin in the core-shell nanoparticles was higher (96.2%) in the presence of EGCG than in its absence (77.9%). Moreover, the water dispersibility and 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity of the nanoparticles were significantly improved in the presence of EGCG. The simulated gastrointestinal tract experiments indicated that curcumin had a high bioaccessibility in the optimized core-shell nanoparticles. Overall, our findings suggest that EGCG can be used to improve the functional properties of curcumin-loaded zein-caseinate nanoparticles, which may increase their use in food, cosmetics, and pharmaceutical applications.

Development of high internal phase Pickering emulsions stabilised by ovotransferrin–gum arabic particles as curcumin delivery vehicles

SummaryThis study explored feasibility of preparing high internal phase Pickering emulsions (HIPEs) as curcumin delivery vehicles. Particles assembled from ovotransferrin (OVT) and gum arabic (GA) could stabilise HIPEs successfully, and OVT–GA particle‐stabilised HIPEs with extremely high oil fraction of 0.90 were stable. Droplet size and rheological properties of OVT–GA particle‐stabilised HIPEs were dependent on both particle concentration and oil fraction. Either increasing particle concentration or decreasing oil fraction resulted in a decrease of droplet size. Increase in storage modulus and viscosity of HIPEs could be achieved by increasing particle concentration or oil fraction. Food structures with controlled shape could be constructed by OVT–GA particle‐stabilised HIPEs. When compared with bulk MCT oil, OVT–GA particle‐stabilised HIPEs improved both extent of lipolysis and curcumin bioaccessibility significantly. These findings provided novel insight into potential application of HIPEs with extremely high oil fractions in nutraceutical delivery systems.

Combining in vitro digestion model with cell culture model: Assessment of encapsulation and delivery of curcumin in milled starch particle stabilized Pickering emulsions

To investigate the encapsulation and oral delivery efficiency of milled starch particles stabilized Pickering emulsions for lipophilic bioactive compounds, in vitro digestion model coupled with Caco-2 cells models were used. Physicochemical and biological properties of curcumin encapsulated Pickering emulsions were analyzed regarding to emulsion structure, curcumin retention, in vitro digestion, in vitro anti-proliferate ability and cellular uptake. Milled starch particles stabilized Pickering emulsion system was able to protect curcumin against harsh gastric conditions. Around 80% of the encapsulated curcumin was retained after 2 h of simulated gastric digestion. By being encapsulated in Pickering emulsion, the bioaccessibility of curcumin was increased from 11% for curcumin in bulk oil phase to 28% under simulated intestinal digestion process. The resulting curcumin-loaded micelle phase from digested emulsion exhibited significant anti-cancer ability and enhanced cellular uptake. This research provides an exploratory study on the possible future application of milled starch particles stabilized Pickering emulsions as nutraceutical delivery vehicles in the creation of novel functional foods.