Enhancing anti-inflammation activity of curcumin through O/W nanoemulsions

High-speed and high-pressure homogenized O/W emulsions using medium chain triacylglycerols (MCT) as oil and Tween 20 as emulsifier, with mean droplet sizes ranging from 618.6 nm to 79.5 nm, have been successfully prepared. The enhanced anti-inflammation activity of curcumin encapsulated in O/W emulsions is evidenced by the mouse ear inflammation model. There is a 43% or 85% inhibition effect of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema of mouse ear for 618.6 nm and 79.5 nm 1% curcumin O/W emulsions, respectively, but a negligible effect is found for 1% curcumin in 10% Tween 20 water solution.     

Effects of enzymatically modified starch on the encapsulation efficiency and stability of water-in-oil-in-water emulsions

The present study was performed to investigate the possibility of using 4-α-glucanotransferase (4αGTase)-treated starch in W/O/W emulsions to increase their encapsulation efficiency (EE) and stability. Emulsions were prepared using soybean oil, polyglycerol polyricinoleate (PGPR), 4αGTase-treated starch and Tween 20. The mean diameter of W/O/W droplets ranged from 4 to 10 μm depending on the sonication time. When the dye was loaded in the internal water phase, the emulsion prepared by sonication for 1 and 2 min showed a high EE of the dye (>90%). The W/O/W emulsion prepared by sonication for 3 min showed an EE of <90%, but this EE was improved by adding 4αGTase-treated starch to the internal water phase. 4αGTase-treated starch was added to the internal water phase of W/O/W emulsions prepared with a low concentration of PGPR, and the PGPR concentration required to maintain an EE >90% was reduced. W/O/W emulsions containing 4αGTase-treated starch also showed better stability against heating and shearing stresses. These results indicated that 4αGTase-treated starch could be used in the preparation of W/O/W emulsions, which would allow the formulation of W/O/W emulsions with a reduced surfactant concentration.     

Stability and characterisation of phospholipid-based curcumin-encapsulated microemulsions

The ternary phase diagram of a curcumin-encapsulated O/W microemulsion system using food-acceptable components, lecithin and Tween 80 as the surfactants and ethyl oleate as the oil phase, was constructed. The stability and characterisation of curcumin in microemulsion were investigated. The results indicated that a composition of curcumin microemulsion (DI water: surfactants (the mole ratio of lecithin/Tween 80 was 0.3): EO = 10:1.7:0.4 in wt ratio) was stable for 2 months with an average diameter of 71.8 ± 2.45 nm, as detected by UV–Vis spectra and diameter distributions. The microemulsion possesses an ability to be diluted with aqueous buffer without destroying its structure for 48 h. A skin permeation study for testing the penetration effect of various curcumin loading in the microemulsions with different particle diameters was also performed and discussed in this contribution.     

Impact of iron encapsulation within the interior aqueous phase of water-in-oil-in-water emulsions on lipid oxidation

Iron (Fe³⁺) was encapsulated within the internal aqueous phase of water-in-oil-in-water (W/O/W) emulsions, and then the impact of this iron on the oxidative stability of fish oil droplets was examined. There was no significant change in lipid droplet diameter in the W/O/W emulsions during 7 days storage, suggesting that the emulsions were stable to lipid droplet flocculation and coalescence, and internal water diffusion/expulsion. The initial iron encapsulation (4 mg/100 g emulsion) within the internal aqueous phase of the water-in-oil (W/O) emulsions was high (>99.75%), although, a small amount leaked out over 7 days storage (≈10 μg/100 g emulsion). When W/O/W emulsions were mixed with fish oil droplets the thiobarbituric acid-reactive substances (TBARS) formed decreased (compared to fish oil droplets alone) by an amount that depended on iron concentration and location, i.e., no added iron < iron in external aqueous phase < iron in internal aqueous phase. These differences were attributed to the impact of W/O droplets on the concentration and location of iron and lipid oxidation reaction products within the system.     

Release rate profiles of magnesium from multiple W/O/W emulsions

Water-in-oil-in-water (W/O/W) emulsions were formulated based on rapeseed oil, olive oil, olein and miglyol. Polyglycerol polyricinoleate and sodium caseinate were used as lipophilic and hydrophilic emulsifiers, respectively. Magnesium was encapsulated in the inner aqueous droplets. Emulsion stability was assayed through particle sizing and magnesium release at two storage temperatures (4 and 25 °C) over 1 month. Irrespective of the oil nature, both the primary W/O and W/O/W emulsions were quite stable regarding the size parameters, with 10-μm fat globules and 1-μm internal water droplets. Magnesium leakage from W/O/W emulsions was influenced by the oil type used in the formulation: the higher leakage values were obtained for the oils characterized by the lower viscosity and the higher proportion of saturated fatty acids. Magnesium release was not due to droplet–globule coalescence but rather to diffusion and/or permeation mechanisms with a characteristic rate that varied over time. In addition, W/O/W emulsions were resistant to various thermal treatments that mimicked that used in pasteurization processes. Finally, when W/O/W emulsions were placed in the presence of pancreatic lipase, the emulsion triglycerides were hydrolysed by the enzyme. These results indicated a possible use of W/O/W emulsions loaded with magnesium ions in food applications.     

Stability and rheology of water-in-oil-in-water multiple emulsions made with protein-polysaccharide soluble complexes

The morphology, stability, and rheological properties of water-in-oil-in-water (W₁/O/W₂) multiple emulsions (ME) stabilized by whey protein concentrate (W)-carboxymethylcellulose (C) soluble complexes (SC_W/C) were evaluated. The interaction pH values (pH_i) to generate SC_W/C were established through zeta potential and turbidity determinations. Six ME variations were prepared using a constant weight ratio (WR) between W and C of 3:1 (where maximum interaction occurred) and by varying the way in which the biopolymers were adsorbed at the interface (layer-by-layer, LL, or pre-formed complex, PF) and pH_i (3.7, 4.0 and 4.3). The ME initial volume-surface diameter (D_3.2) of the oil droplets ranged from 2.4 to 3.2 μm, which on turn contained numerous flocculated water droplets. Higher viscoelastic moduli values (G′ and G″), more pronounced shear thinning behaviour and smaller changes in droplet size with storage time were displayed by ME made with a pH_i value of 4.3, WR_3:1, and LL biopolymers adsorption technique.     

Effects of solubility characteristics of sensitiser and pH on the photooxidation of oil in tuna oil-added acidic O/W emulsions

The effects of sensitisers and pH on the oil oxidation of acidic O/W emulsions were studied under light by measuring hydroperoxide content and headspace oxygen consumption in the emulsions. The emulsions consisted of canola and tuna oil (2:1 w/w, 32%), diluted acetic acid (64%), egg yolk powder (4%), chlorophyll b or erythrosine (5 μM), and/or diazabicyclooctane (DABCO) or sodium azide (0.5 M). The emulsion pH values were 2.67, 3.68, and 6.27. Chlorophyll increased oil oxidation in the emulsion under light via singlet oxygen production while erythrosine did not. DABCO significantly decreased photooxidation of the oil containing chlorophyll, suggesting singlet oxygen involvement. However, sodium azide increased photooxidation of the oil containing chlorophyll possibly via azide radical production under acidic conditions. The oil photooxidation was higher in the emulsion containing chlorophyll at pH 6.27 than at pH 2.67 or 3.68, primarily by singlet oxygen and secondarily by free radicals produced from hydroperoxide decomposition.     

Continuous preparation of O/W nano-emulsion by the treatment of a coarse emulsion under subcritical water conditions

A coarse oil-in-water (O/W) emulsion, the oil phase of which was octanoic acid, was prepared at a very low surfactant concentration using a rotor/stator homogenizer. The emulsion was passed in a stainless steel tube immersed in an oil bath at 220 °C at a residence time of 60 s, and then mixed with the surfactant solution to produce a finely dispersed emulsion. The diameter of oil droplets in the fine emulsion was ca. 40 nm at the weight ratio of surfactant to oil of ca. 0.35 or higher.     

Antioxidant and emulsifying properties of potato protein hydrolysate in soybean oil-in-water emulsions

The efficacy of a previously developed antioxidative potato protein hydrolysate (PPH) for the stabilisation of oil droplets and inhibition of lipid oxidation in soybean oil-in-water (O/W) emulsions was investigated. Emulsions (10% lipid, pH 7.0) with PPH-coated oil droplets were less stable than those produced with Tween 20 (P < 0.05). However, the presence of PPH, whether added before or after homogenisation with Tween 20, retarded emulsion oxidation, showing reduced formation of peroxides up to 53.4% and malonaldehyde-equivalent substances up to 70.8% after 7-d storage at 37 °C (P < 0.05), when compared with PPH-free emulsions. In the emulsions stabilised by PPH + Tween 20, 8–15% of PPH was distributed at the interface. Adjustment of the pH from 3 to 7 markedly increased ζ-potential of such emulsions (P < 0.05). Inhibition of lipid oxidation by PPH in soybean O/W emulsions can be attributed to both chemical and physical (shielding) actions.     

Characteristics and composition of Washingtonia filifera (Linden ex André) H. Wendl. seed and seed oil

Characteristics of seeds and oil extracted from Washingtonia filifera seeds are evaluated. The percentage composition of the W. filifera seeds is: ash 1.37%, oil 16.30%, protein content 3.46%, total carbohydrate 77.19% and moisture 3.22%. The major nutrients (mg/100 g of seeds) found in the seeds are: potassium (67.33), magnesium (34.35), calcium (187.85) and phosphorus (23.26). Physicochemical properties of the oil include: iodine value 67.33 g/100 g of oil; saponification value, 191.63 mg KOH/g of oil; refractive index (25 °C), 1.469; unsaponifiable matter, 0.83%; acidity, 0.41%; p-anisidine value, 0.87; peroxide value, 7.60 mEq O₂/kg of oil; carotenoid content 14.8 mg/100 g and the chlorophyll content = 0.13 mg/100 g. W. filifera seed oil shows some absorbance in the UV-B and UV-C ranges with potential use as a broad spectrum UV protectant. The oil contains high levels of oleic acid (40.60%) followed by lauric acid (17.87%), linoleic acid (16.26%), myristic acid (11.43%) and palmitic acid (9.23%). The triacylglycerols (TAGs) with equivalent carbon number ECN 44 (20.47%) are dominant, followed by TAGs ECN 46 (16.71%), TAGs ECN 42 (15.43%) and TAGs ECN 48 (15.41%). The DSC melting curves reveal that: melting point = 2.25 °C and melting enthalpy = 82.34 J/g. γ-Tocotrienol is the major tocol (72%) with the rest being δ-tocotrienol and α-tocotrienol. The results of the present analytical study show that W. filifera seed oil could be used in cosmetic, pharmaceutical and food products.     

Oxidative properties of lactoferrins of different iron-saturation in an emulsion consisting of metmyoglobin and cod liver oil

Lactoferrins (LFs) at iron-saturation 8 (native) and 100%, respectively, were present in an oil-in-water (O/W) emulsion composed of 5% (w/v) cod liver oil (CLO) and metmyoglobin (metMb) in 50 mM phosphate buffer at pH 6.0. Initially both LFs acted as antioxidants and reduced initial peroxide formation, but after 48 h holo LF revealed the most peroxides but the least trienes. Native LF (0.8 mg/ml) gave the highest (p < 0.05) amounts of lipid derived volatiles after 48 h incubation at 4 °C. Both LFs gave similar increases in adducts to metMb with time. The most extensive aggregation induced by radicals or peroxides was found for native LF. The results pointed at reactions at the O/W interphase as highly influential for lipid and protein oxidation kinetics. Added ascorbic acid (1 mM), however, behaved as an antioxidant in the pro-oxidative oil-in-water emulsion system and prevented lipid degradation and protein adductation as well as protein aggregation.     

Catastrophic inversion and rheological behavior in soy lecithin and Tween 80 based food emulsions

Emulsions inversion occurs in many industrial processes and may be influenced by the formulation conditions, composition and emulsification protocols. In this work, the influence of emulsifiers and stirring on catastrophic inversion (O/W to W/O) was evaluated. Emulsions were prepared with different stirring rates, using soy lecithin and Tween 80, at 2 and 5 wt%. The aqueous phase was distilled water with 1 wt% NaCl and the oil phase was soy oil. These emulsions were analyzed by conductivity, stability, microscopy and rheology assays. The most stable emulsions presented inversion with a smaller amount of the external phase. Rheological analysis showed that, with a higher concentration of emulsifier, it is better to use Tween 80 when lower viscosity is desired, while soy lecithin is more appropriate for higher viscosity products. The oscillatory tests showed that while the emulsions prepared using Tween 80 exhibited concentrated solution behavior, those prepared with soy lecithin exhibited strong gel behavior.     

Alginate‐Based Emulsion Template Containing High Oil Loading Stabilized by Nonionic Surfactants

Oil‐in‐water (O/W) emulsion‐gel systems containing high oil payloads are of increasing interest for food applications because of the reduction in encapsulation cost, consumption frequency or volume of food products. This study shows a facile approach to prepare stable alginate‐based O/W emulsions at high oil loading using a mixture of nonionic surfactants (Tween 80 and Span 20) as a template to form gelled‐emulsions. The synergistic effects of alginate and surfactants on the O/W emulsion properties were evaluated in terms of oil droplet size and emulsion stability. At 2% (w/v) of alginate and 1% (w/v) of surfactants, the size distribution of oil droplets was narrow and monomodal, even at an oil loading of 70% (v/v). The emulsions formed were stable against phase separation. The oil droplet size could be further reduced to below 1 μm using a high‐shear homogenizer. The emulsions formed could be easily molded and gelled into solids of different shapes via ionic gelation. The findings of this study create possible avenues for applications in food industries.     

Assessment of Escherichia coli O157:H7-specific bacteriophages e11/2 and e4/1c in model broth and hide environments

The efficacy of bacteriophages e11/2 and e4/1c as potential biocontrol agents for Escherichia coli O157:H7 in food applications was assessed under conditions relevant to the food chain environment. The stability of each phage was determined following exposure to varying environmental conditions (pH, temperature, water activity, and sodium chloride) and the ability of each phage to infect and reduce E. coli O157:H7 numbers under selected conditions was also examined. Both e11/2 and e4/1c significantly (p < 0.05) reduced numbers of E. coli O157:H7 when exposed to pH values ranging from pH > 4 to pH 9, temperatures from 4 °C to 37 °C, water activity values of 0.87 or 0.91 to 1.00 and NaCl concentrations of 1% to 2.5%. Subsequently, a cocktail of both phages was used (e11/2 and e4/1c) to assess reduction of E. coli O157:H7 on cattle hide pieces. This involved inoculating pieces of hide (20 × 20 cm) with E. coli O157:H7 (approximately 10⁶ cfu/cm²) which were subsequently treated with either a suspension of a phage cocktail, consisting of e11/2 and e4/1c (multiplicity of infection of 1000 and 10,000, respectively) or water or not treated. Two different investigations were carried out; immediately or 1 h after treatment application was performed in different experiments. Swab samples taken immediately after phage treatment showed no significant (p > 0.05) reduction of E. coli O157:H7 numbers compared to the water treated or untreated samples. However, an extended exposure time of 1 h following phage application revealed a significant reduction (p < 0.05) (1.5 log₁₀ cfu/cm² reduction) in E. coli O157:H7 numbers compared to the numbers recovered on samples treated with water only. These findings demonstrate the potential use of e11/2 and e4/1c phages as a biocontrol agent for E. coli O157:H7 within various stages of the food chain, including on cattle hide.     

Polyphenolic content and antioxidant activity of Eugenia pollicina leaf extract in vitro and in model emulsion systems

The polyphenolic profile of a leaf extract of the Mauritian endemic plant, Eugenia pollicina, was assessed as a source of natural antioxidants. The amounts of flavan-3-ol derivatives determined by HPLC, were in the order of (−)-epicatechin (EC) > (−)-epigallocatechin gallate (EGCG) > (+)-catechin (C) > (−)-epicatechin gallate (ECG) with the levels of Procyanidin B2 and B1 dimers ranging from 1 to 3 mg g⁻¹ FW. The trolox equivalent antioxidant capacity and ferric reducing antioxidant power values were 796 ??mol g⁻¹ FW and 302 ??mol g⁻¹ FW respectively. E. pollicina extracts also strongly inhibited the FeCl₃ and ascorbate-dependent microsome lipid peroxidation, a function that is linked to their flavonoid contents. The extent of DNA damage induced by the extract under study in the copper-phenanthroline assay was lower than the effect of a reference of 240 ??M ascorbate. E. pollicina extracts also inhibited lipid autoxidation in the 30% (v/v) olive oil and soybean oil oil-in-water (O/W) emulsions and was effective in slowing down the formation of hydroperoxides in the emulsions during 13 days storage at 40 °C as determined by the peroxide, conjugated diene and para-anisidine values. The high levels of total phenolics, flavonoids and procyanidins measured indicate that E. pollicina is a potential source of antioxidants relevant to the maintenance of oxidative stability of the food matrix, cosmetics and/or pharmaceutical preparations.     

Effects of addition of essential oils and monensin premix on digestion, ruminal fermentation, milk production, and milk composition in dairy cows

Four ruminally cannulated, lactating Holstein cows were used in a 4 × 4 Latin square design (28-d periods) with a 2 × 2 factorial arrangement of treatments to study the effects of dietary addition of essential oils (0 vs. 2 g/d; EO) and monensin (0 vs. 350 mg/d; MO) on digestion, ruminal fermentation characteristics, milk production, and milk composition. Intake of dry matter averaged 22.7 kg/d and was not significantly affected by dietary additives. Apparent digestibilities of dry matter, organic matter, neutral detergent fiber, and starch were similar among treatments. Apparent digestibility of acid detergent fiber was increased when diets were supplemented with EO (48.9 vs. 46.0%). Apparent digestibility of crude protein was higher for cows fed MO compared with those fed no MO (65.0 vs. 63.6%). Nitrogen retention was not changed by additive treatments and averaged 27.1 g/d across treatments. Ruminal pH was increased with the addition of EO (6.50 vs. 6.39). Ruminal ammonia nitrogen (NH₃-N) concentration was lower with MO-supplemented diets compared with diets without MO (12.7 vs. 14.3 mg/100 mL). No effect of EO and MO was observed on total volatile fatty acid concentrations and molar proportions of individual volatile fatty acids. Protozoa counts were not affected by EO and MO addition. Production of milk and 4% fat-corrected milk was similar among treatments (33.6 and 33.4 kg/d, respectively). Milk fat content was lower for cows fed MO than for cows fed diets without MO (3.8 vs. 4.1%). The reduced milk fat concentration in cows fed MO was associated with a higher level of trans-10 18:1, a potent inhibitor of milk fat synthesis. Milk urea nitrogen concentration was increased by MO supplementation, but this effect was not apparent when MO was fed in combination with EO (interaction EO × MO). Results from this study suggest that feeding EO (2 g/d) and MO (350 mg/d) to lactating dairy cows had limited effects on digestion, ruminal fermentation characteristics, milk production, and milk composition.     

Synergistic effects of polyglycerol ester of polyricinoleic acid and sodium caseinate on the stabilisation of water–oil–water emulsions

The inherent thermodynamic instability of water–oil–water (W/O/W) emulsions has restrictions for their application in food systems. The objective of this study was to develop a food grade W/O/W emulsions with high yield and stability using minimal concentrations of surfactants. Emulsions were prepared using soybean oil, polyglycerol ester of polyricinoleic acid (PGPR) alone or in combination with sodium caseinate (NaCN) as emulsifier(s) for primary water-in-oil (W/O) emulsions and NaCN as the sole emulsifier for secondary W/O/W emulsions. Increasing the concentration of PGPR (0.5–8%w/v) had no effect on the droplet sizes of the resulting W/O/W emulsions. However, significant increases in droplet sizes of W/O/W emulsions were observed when the concentration of NaCN in external phase was reduced from 0.5 to 0.03% (w/v) (p<0.05). Percentage yields of emulsions (using a water-soluble dye) improved when PGPR concentration in the inner phase was increased from 0.5 to 8% (w/v). A stable W/O/W emulsion with a yield >90% could be prepared with 4% (w/v) PGPR alone as primary hydrophobic emulsifier and 0.5% (w/v) NaCN as external hydrophilic emulsifier. The concentration of PGPR in the inner phase could be reduced to 2% (w/v) without affecting the yield and stability of the W/O/W emulsion by partially replacing PGPR with 0.5% (w/v) NaCN, which was added to the aqueous phase of the primary W/O emulsion. The results indicate that a possible synergistic effect may exist between PGPR and NaCN, thus allowing formulation of double emulsions with reduced surfactant concentration.     

Formulation of a cosurfactant-free O/W microemulsion using nonionic surfactant mixtures

ABSTRACT:  A cosurfactant-free O/W microemulsion composed of oil, a mixture of hydrophilic and hydrophobic surfactants, and water has been developed using food-grade components as a nutrient delivery system. We started our investigation to monitor the phase behavior of this system based on a hydrophilic surfactant (Tween 80). From a phase diagram, the weight ratio of 5.4:33.8:60.8 = oil:surfactant:water was selected as a combination ratio for the O/W microemulsion system. We also investigated the combination effect of different hydrophobic surfactants to Tween 80 on microemulsion formation. Use of hydrophobic surfactants with Tween 80 produced smaller droplets than Tween 80 alone. Rheological studies showed that all microemulsions followed shear-thinning behavior. The turbidity of microemulsions did not change after accelerated stability tests, indicating that this microemulsion system was stable under the given harsh conditions. When docosahexaenoic acid (DHA) oil was applied to this microemulsion system, the particle size and the turbidity were not significantly changed. Dilution with a different aqueous medium, either water or acidic fluid, did not significantly change the microemulsion turbidity. DHA oil incorporated in microemulsion showed higher oxidation stability than free DHA oil.     

Chemical analysis,antioxidant, antiinflammatory and anticholinesterase activities of Origanum ehrenbergii Boiss and Origanum syriacum L. essential oils

The essential oils of Origanum ehrenbergii and O. syriacum collected in Lebanon were analysed by GC and GC–MS and evaluated for their anticholinesterase, NO production inhibitory activities, and antioxidant properties. O.ehrenbergi essential oil was characterised by the presence of 37 components, representing 94.9% of the total oil of which thymol (19%) and p-cymene (16.1%) were the main abundant compounds. Thirty-six compounds characterised the O.syriacum essential oil, representing 90.6% of the total oil. The most abundant components were thymol (24.7%) and carvacrol (17.6%). O. ehrenbergii demonstrated interesting scavenging effects on DPPH with an IC₅₀ value of 0.99 μg/ml. In addition, both O. ehrenbergii and O. syriacum oils inhibited oxidation of linoleic acid after 30 min of incubation, as well as after 60 min of incubation with IC₅₀ values of 42.1 and 33.6 μg/ml, and 46.9 and 58.9 μg/ml, respectively. Interestingly, O. ehrenbergii oil inhibited NO production in the murine monocytic macrophage cell line RAW 264.7 with an IC₅₀ value of 66.4 μg/ml. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition was assessed by modifications of the Ellman’s method. O. ehrenbergii exhibited a strong activity against both cholinesterases with IC₅₀ values of 0.3 μg/ml. The data suggest that O. ehrenbergii and O. syriacum oils could be used as a valuable new flavour with functional properties for food or nutriceutical products with particular relevance to supplements for the elderly.