Improving in vitro bioaccessibility and bioactivity of carnosic acid using a lecithin-based nanoemulsion system.

As a phenolic terpenoid, carnosic acid (CA) mainly exists in rosemary, which can be effectively used for the treatment of degenerative and chronic diseases by taking advantage of its health-promoting bioactivities. However, the low solubility and dissolution of CA in aqueous solutions at ambient and body temperatures result in low stability and bioaccessibility during the digestion process, which limits its application scope in the functional foods industry. In this regard, a lecithin based nanoemulsion system (CA-NE) is employed in the present work to enhance the bioaccessibility and bioactivities of CA. It is revealed that the CA-NE under investigation exhibits high loading capacity (2.80 ± 0.15%), small particle size (172.0 ± 3.5 nm) with homogeneous particle distribution (polydispersity index (PDI) of 0.231± 0.025) and high repulsive force (zeta potential = -57.2 ± 0.24 mV). More importantly, the bioaccessibility of CA-NE is improved by 2.8-fold compared to that of CA in MCT oil. In addition, the cellular antioxidant assay (CAA) and cellular uptake study of the CA-NE in HepG2 cell models demonstrate a longer endocytosis process, suggesting the well-controlled release of CA from CA-NE. Furthermore, an improved anti-inflammatory activity was evaluated via the inhibition of the pro-inflammatory cytokines, nitric oxide (NO) and TNF-α production in LPS-stimulated RAW 264.7 macrophage cells. The results clearly demonstrated a promising application of CA-NE as a functional food.

Corrigendum to "Improved bioaccessibility of polymethoxyflavones loaded into high internal phase emulsions stabilized by biopolymeric complexes: A dynamic digestion study via TNO's gastrointestinal model"[Curr Res Food Sci, Volume 2 (June 2020) 11-19].

[This corrects the article DOI: 10.1016/j.crfs.2019.11.007.].

Improving the bioaccessibility and bioavailability of carnosic acid using a lecithin-based nanoemulsion: complementary in vitro and in vivo studies.

Carnosic acid (CA) represents one of the most effective antioxidants that can be applied for the prevention of degenerative and chronic diseases. However, the intrinsic hydrophobic nature of CA results in low solubility and poor dissolution in the gastrointestinal (GI) tract, which limits its applications in a variety of functional food systems. In order to address these issues, we encapsulated CA in a lecithin-based nanoemulsion (CA-NE) to improve its bioaccessibility and bioavailability which are evaluated using in vitro and in vivo digestion models. The CA-NE demonstrated a loading capacity of 2.6-3.0%, an average particle size of 165 nm, a ζ-potential value of -57.2 mV, and good stability during 4-weeks of storage at 4, 25, and 37 °C. The in vitro static pH-stat lipolysis model and dynamic TNO gastrointestinal (TIM-1) model demonstrated a 12.6 and 5.6 fold increase in the total bioaccessibility of CA encapsulated in nanoemulsion, respectively, as opposed to CA in suspension form. Moreover, the in vivo pharmacokinetics study on a rat model (Male Sprague Dawley) confirmed that the bioavailability of CA in nanoemulsion showed a 2.2 fold increase, as compared to that of CA in suspension form. In conclusion, the bioaccessibility and bioavailability of CA were remarkably improved by encapsulation of CA in a lecithin-based nanoemulsion. Moreover, the combined in vitro and in vivo study could serve as a useful approach for the comprehensive evaluation of oral lipid-based delivery systems.

Improved bioaccessibility of polymethoxyflavones loaded into high internal phase emulsions stabilized by biopolymeric complexes: A dynamic digestion study via TNO's gastrointestinal model.

In this work, the bioaccessibility of polymethoxyflavones (PMFs) loaded in high internal phase emulsions (HIPE, ϕoil = 0.82) stabilized by whey protein isolate (WPI)-low methoxy pectin (LMP) complexes was evaluated using in vitro lipolysis and dynamic in vitro intestinal digestion studies. PMFs loaded HIPE was prepared by using aqueous dispersion of pre-formed biopolymeric complexes (WPI-LMP, 2:1 ratio) as the external phase and medium chain triglycerides oil (containing PMFs extracted from citrus peel) as the dispersed phase. The in vitro lipolysis study revealed that PMFs in HIPE became bioaccessible much higher than PMFs in medium chain triacylglycerols oil (MCT oil). In addition, by simulating the entire human gastrointestinal (GI) tract, the GI model TIM-1 demonstrated a 5- and 2-fold increase in the total bioaccessibility for two major PMFs encapsulated in HIPE, i.e. tangeretin (TAN) and nobiletin (NOB), respectively, as opposed to PMFs in MCT oil. Together these results from the digestion study showed that the incorporation of a high amount of PMFs into the viscoelastic matrix of HIPE could represent an innovative and effective way to design an oral delivery system. Such a system could be used to control and to improve the delivery of lipophilic bioactive compounds within the different compartments of the digestive tract, especially the human upper GI tract.

Hydrogels assembled from ovotransferrin fibrils and xanthan gum as dihydromyricetin delivery vehicles.

The present study aimed to assemble protein fibril-polysaccharide hydrogels as nutraceutical delivery vehicles. Turbidity titrations confirmed that complexations between ovotransferrin (OVT) fibrils and xanthan gum (XG) indeed occurred, and electrostatic interaction was the major driving force of OVT fibril-XG complexation. After optimization of the pH and acidifier, stable OVT fibril-XG hydrogels could be fabricated by adjusting the pH to 4.0 with glucono delta-lactone. To better understand the physicochemical properties of OVT fibril-XG gel, characterization of XG gel was also conducted. Scanning electron microscopy indicated that OVT fibril-XG gel had a denser network than XG gel. Rheological measurements revealed that OVT fibril-XG gel had higher gel strength and viscosity than XG gel. OVT fibril-XG gel and XG gel could be used as dihydromyricetin (DMY) delivery vehicles with a higher DMY loading (2 mg mL-1). DMY release was investigated using an in vitro gastrointestinal digestion model. All DMY was released from OVT fibril-XG gel after gastrointestinal digestion, and only 41.7% of DMY was released from XG gel after gastrointestinal digestion, indicating that OVT fibril-XG gel was more efficient in DMY delivery. DMY was released via a non-Fickian transport mechanism in both OVT fibril-XG gel and XG gel. The results of this study could provide new insight into the assembly of protein fibril-polysaccharide hydrogels and rational design of hydrogels as nutraceutical delivery vehicles.

Whey protein isolate-low methoxyl pectin nanocomplexes improve physicochemical and stability properties of quercetin in a model fat-free beverage.

In this study, whey protein isolate (WPI)-low methoxyl pectin (LMP) electrostatic complexes were used to encapsulate quercetin (Q) in a model fat-free beverage system. The effect of the pH and WPI : LMP ratio was first studied to form soluble complexes with optimal physical properties, in terms of the hydrodynamic diameter, surface charge, and yield. Based on the results, pH 5.0 and a 2 : 1 (w/w) ratio of WPI : LMP were selected for encapsulation of Q. The stoichiometry of the binding (n) and the binding constant (Kb) of WPI:Q were evaluated at pH values of 5.0 and 7.0 at room temperature. The Q-loaded WPI:LMP nanocomplexes were produced by mixing WPI with Q at two loading concentrations corresponding to 5 : 1 and 1 : 1 WPI : Q molar mixing ratios, followed by the addition of LMP and pH adjustment to 5.0. The microstructure of Q-loaded WPI:LMP complexes was investigated by cryo-SEM imaging. Q was efficiently entrapped at two loading concentrations with an efficiency of about 97%. Q-loaded WPI:LMP complexes showed physical stability during storage and high temperature processing, as well as in the presence of challenging formulation conditions such as a high sugar concentration or salt addition (at a limited concentration). The stability of encapsulated Q against UV irradiation was approximately 4 times better than that of free Q. Moreover, Q-loaded WPI:LMP complexes were also lyophilized into dry powder, which can be useful for practical application in food products.

High internal phase emulsion (HIPE)-templated biopolymeric oleofilms containing an ultra-high concentration of edible liquid oil.

We report, for the first time, the fabrication of oleofilms (containing more than 97 wt% edible liquid oil) using high internal phase emulsions (with oil volume fraction φoil = 0.82) as templates. Advanced microscopy studies revealed an interesting microstructure of these films where jammed oil droplets were embedded in a dried matrix of biopolymeric complexes.

High internal phase emulsions stabilized solely by whey protein isolate-low methoxyl pectin complexes: effect of pH and polymer concentration.

In recent years, there has been significant progress in edible emulsion technology especially with respect to creating and stabilizing surfactant-free emulsion systems for food applications. In this paper, we demonstrate the fabrication of high internal phase emulsions (HIPE) (φoil = 0.82) stabilized using colloidal complexes of non-gelling biopolymers (at concentrations as low as 0.3 wt%). The colloidal complexes were pre-formed by combining whey protein isolate (WPI) and low-methoxyl pectin (LMP) at three different pH values (i.e. pH 3.5, 4.5, 5.5) and used further for fabricating stable HIPEs. In addition to the effect of pH, the influence of total biopolymer concentration on the formation and properties of HIPEs was also evaluated. Depending on the total concentration of biopolymers used, the WPI-LMP complexes (formed at pH 4.5) showed a Z-average diameter in the range of 250-350 nm. It was found that the formation of HIPEs was strongly influenced by the pH of the colloidal complexes. At a pH close to the isoelectric point of WPI (≈pH 4.8) and WPI-LMP complexes (≈pH 3.4), severe aggregation of colloidal particles occurred, resulting in poor formation and stability of HIPEs. On comparing the stabilization behaviour of the complexes with the uncomplexed protein, it was noticed that the former provided comparatively better stabilization to the HIPEs against coalescence at pH 4.5 and 5.5. Based on the rheological data (low amplitude oscillatory shear rheology and flow measurements), all HIPE samples showed viscoelastic and shear-thinning behaviour. We believe that such viscoelastic gel-like systems could find potential commercial applications in the development of label-friendly novel food products with interesting textures.