Double Emulsion Research Articles

Destabilization of a model O/W/O double emulsion: From bulk to interface

Oil-in-water-in-oil (O/W/O) double emulsions are considered an advanced oil-structuring technology that can accomplish multi-functions to improve food quality and nutrition. However, this special structure is thermodynamically unstable. This study formulated a model O/W/O double emulsion with standard surfactants, Tween 80 (4 %) and polyglycerol polyricinoleate (PGPR, 5 %), using a traditional two-step method with different homogenization parameters. Cryo-SEM and GC-FID results show that O/W/O emulsions were successfully formulated, and the release rate (RR) of medium-chain triglycerides (MCT) oil from the inner oil to the outer oil phase increased significantly with 2nd homogenization speed increasing, respectively. Interestingly, the RR of all samples reached about 75 % after 2 months of storage, suggesting that O/W/O emulsions were highly unstable.To explain the observed instability, dynamic interfacial tension and interfacial rheology were performed using a drop shape tensiometer. Results demonstrated that unadsorbed Tween 80 in the intermediate aqueous phase was a key factor in markedly decreasing the interfacial properties of the outer PGPR-assembled film by affecting the interfacial rearrangement. Additionally, it was found that the MCT release showed a positive correlation with the Tween 80 concentration, demonstrating that the formed Tween 80 micelles could transport oil molecules to strengthen the emulsion instability.Taken together, this study reveals the destabilization mechanism of model O/W/O surfactants-stabilized emulsions from bulk to interface, providing highly relevant insights for the design of stable O/W/O double emulsions.

Constructing multiple hydrogen bonds in adsorbent for selective adsorption of acteoside

The efficient adsorption of acteoside (ACT) was essential for the development and utilization of the active ingredients of Cistanche tubulosa. In this study, the adsorbent of hydrophilic imidazole polyionic liquids P(StDVB-[C4vim][BF4]) was synthesized based on a double emulsion interfacial polymerization method to adsorb hydrophilic ACT. The as-prepared P(StDVB-[C4vim][BF4]) showed an excellent adsorption performance, and the adsorption capacity and selectivity were 114.31 mg/g and 4.31, respectively. This was mainly attributed to as follows: firstly, P(StDVB-[C4vim][BF4]) possessed multiple hydrogen bond receptors due to the introduction of functional monomer [C4vim][BF4]. The multiple hydrogen bond receptors provided the F atoms and N atoms to form multiple hydrogen bonds with the ACT, realizing the efficient adsorption of ACT. Secondly, the hierarchical porous structure had plenty of micro-mesopores and macropores. The micropores prefer screened small molecules, enhancing the selective adsorption of ACT, the mesoporous pores greatly improved the diffusion ability of ACT in the pores of P(StDVB-[C4vim][BF4]), and the macropores reduced transportation restrictions and facilitated the entry of ACT. Finally, the P(StDVB-[C4vim][BF4]) contained hydrophilic imidazole group, enhancing the affinity between P(StDVB-[C4vim][BF4]) and ACT. Thus, P(StDVB-[C4vim][BF4]) can effectively adsorb ACT. The multiple hydrogen bonds were suggested as the major driving forces for adsorbing P(StDVB-[C4vim][BF4]) and ACT. In addition, P(StDVB-[C4vim][BF4]) was conveniently regenerated up to 6 times. Therefore, the P(StDVB-[C4vim][BF4]) had potential application for adsorbing active ingredients of natural products.

Development of novel polymer haemoglobin based particles as an antioxidant, antibacterial and an oxygen carrier agents

This innovative work aims to develop highly biocompatible and degradable nanoparticles by encapsulating haemoglobin (Hb) within poly-ε-caprolactone for novel biomedical applications. We used a modified double emulsion solvent evaporation method to fabricate the particles. A Scanning electron microscope (SEM) characterized them for surface morphology. Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet–visible spectroscopies (UV–visible) elucidated preserved chemical and biological structure of encapsulated haemoglobin. The airproof equilibrium apparatus obtained the oxygen-carrying capacity and P50 values. The DPPH assay assessed free radical scavenging potential. The antibacterial properties were observed using four different bacterial strains by disk diffusion method. The MTT assay investigates the cytotoxic effects on mouse fibroblast cultured cell lines (L-929). The MTT assay showed that nanoparticles have no toxicity over large concentrations. The well-preserved structure of Hb within particles, no toxicity, high oxygen affinity, P50 value, and IC50 values open the area of new research, which may be used as artificial oxygen carriers, antioxidant, and antibacterial agents, potential therapeutic agents as well as drug carrier particles to treat the cancerous cells. The novelty of this work is the antioxidant and antibacterial properties of developed nanoparticles are not been reported yet. Results showed that the prepared particles have strong antioxidant and antibacterial potential.

Effects of folate-chicory acid liposome on macrophage polarization and TLR4/NF-κB signaling pathway in ulcerative colitis mouse

BackgroundChichoric acid (CA) is a major active ingredient found in chicory and Echinacea. As a derivative of caffeic acid, it has various pharmacological effects. PurposeDue to the unclear etiology and disease mechanisms, effective treatment methods for ulcerative colitis (UC) are currently lacking. The study investigated the therapeutic effects of the folate-chicory acid liposome on both LPS-induced macrophage inflammation models and dextran sulfate sodium (DSS)-induced mouse UC models. MethodsFolate-chicory acid liposome was prepared using the double emulsion ultrasonic method with the aim of targeting folate receptors specifically expressed on macrophages. The study investigated the therapeutic effects of the folate-chicory acid liposome on both LPS-induced macrophage inflammation models and DSS -induced mouse UC models. Furthermore, the effects of the liposomes on macrophage polarization and their underlying mechanisms in UC were explored. ResultsThe average particle size of folate-chicory acid liposome was 120.4 ± 0.46 nm, with an encapsulation efficiency of 77.32 ± 3.19 %. The folate-chicory acid liposome could alleviate macrophage apoptosis induced by LPS, decrease the expression of inflammatory factors in macrophages, enhance the expression of anti-inflammatory factors, inhibit macrophage polarization towards the M1 phenotype, and mitigate cellular inflammation in vetro. In vivo test, folate-chicory acid liposome could attenuate clinical symptoms, increased colon length, reduced DAI scores, CMDI scores, and alleviated the severity of colonic histopathological damage in UC mice. Furthermore, it inhibited the polarization of macrophages towards the M1 phenotype in the colon and downregulated the TLR4/NF-κB signaling pathway, thereby ameliorating UC in mice. ConclusionFolate-chicory acid liposome exhibited a uniform particle size distribution and high encapsulation efficiency. It effectively treated UC mice by inhibiting the polarization of macrophages towards the M1 phenotype in the colon and downregulating the TLR4/NF-κB signaling pathway.

A Simple Non-Embedded Single Capillary Device for On-Demand Complex Emulsion Formation.

This study includes an examination of the design, fabrication, and experimentation of a rudimentary droplet generator. The device has potential applications in on-demand double and higher-order emulsions as well as tailored emulsions with numerous cores. The phenomenon of a pendant double droplet creation is observed when an inner phase is transported through a capillary, while a middle phase envelops the external surface of the capillary. This leads to the occurrence of a pinching-off process at the tip of the pulled capillary. Following this, the double droplet is introduced into a container that is filled with the outer phase. The present study examines the force equilibrium throughout the droplet break-up process and aims to forecast the final morphology of the droplets within the container by considering the impact of interfacial tension ratios. The shell thickness in a core-shell formation can be calculated based on the inner and middle phase flow rates as well as the middle droplet formation period. The present platform, which enables the simple production of double and higher emulsions, exhibits promising prospects for the controlled manufacturing of complex emulsions. This technology holds potential for various applications, including the experimental exploration of collision behavior or electro-hydrodynamics in emulsions as well as millimeter-size engineered microparticle fabrication.

An Updated Comprehensive Overview of Different Food Applications of W1/O/W2 and O1/W/O2 Double Emulsions

Double emulsions (DEs) present promising applications as alternatives to conventional emulsions in the pharmaceutical, cosmetic, and food industries. However, most review articles have focused on the formulation, preparation approaches, physical stability, and release profile of encapsulants based on DEs, particularly water-in-oil-in-water (W1/O/W2), with less attention paid to specific food applications. Therefore, this review offers updated detailed research advances in potential food applications of both W1/O/W2 and oil-in-water-in-oil (O1/W/O2) DEs over the past decade. To this end, various food-relevant applications of DEs in the fortification; preservation (antioxidant and antimicrobial targets); encapsulation of enzymes; delivery and protection of probiotics; color stability; the masking of unpleasant tastes and odors; the development of healthy foods with low levels of fat, sugar, and salt; and design of novel edible packaging are discussed and their functional properties and release characteristics during storage and digestion are highlighted.

Abstract WP315: Pharmacological Validation of Advanced Gamma Peptide Nucleic Acid (PNA) Based miR Inhibitors for Ischemic Stroke Treatment

Backgrounds: Our prior work demonstrated the potential of targeting miR-141-3p to mitigate ischemic stroke damage. In this study, we aimed to synthesize and validate more advanced and efficacious gamma peptide nucleic acid (PNA) based anti-miR 141-3p inhibitors, comparing them with regular PNA and phosphothiorate (PS) based counterparts. These inhibitors were subsequently encapsulated in poly(lactide-co-glycolide) (PLGA)-based nanoparticles (NPs) for treatment in a mouse model of ischemic stroke. Methods: In-house synthesis yielded PS, PNA, and gamma-PNA anti-miR 141-3p, encapsulated in PLGA NPs via double emulsion solvent evaporation. After physiochemical characterization, in vitro safety and efficacy were evaluated in HEK293 cells via MTT, LDH cytotoxicity assays, and qPCR for gene expression. In vivo efficacy studies employed the most potent gamma-PNA based anti-miR 141-3p, administered intraperitoneally 4 hours after 60-minute of transient middle cerebral artery occlusion (MCAO). Mice were sacrificed at 3 (acute) or 30 (chronic) days post-stroke. Acute cohort brain tissues were analysed for miRNA and target mRNA levels, along with infarct volume. Chronic cohort mice were subjected to weekly behavioral task to major sensorimotor deficit or recovery. Results: twenty-four-hour exposed HEK-293 cells were no sign of mortality and toxicity at concentration range of 0.015-1.5ug/mL of various anti-miR 141-3p. Gamma-PNA based anti-miR exhibited notably higher efficacy in inhibiting miR-141-3p (IC50=0.05ug/mL) compared to PS (IC50>1.5ug/mL) or regular PNA (IC50>1.5ug/mL). A single dose of gamma-PNA-based anti-miR significantly reduced (P<0.05 vs. Scramble control) infarct injury and brain tissue miR-141-3p levels (>2-fold vs. scramble control). Gamma-PNA treatment also led to swift improvement in sensorimotor deficits in the rotarod task. Conclusion: NPs of gamma-PNA-based anti-miR 141-3p were both safe and potent in vitro and in vivo. They effectively mitigated infarct injury, improved neurobehavioral deficits, demonstrating promising translational potential for ischemic stroke treatment. In future we aim to explore more mechanistic studies to explore it mode of action.

Oral delivery of the amylin receptor agonist pramlintide

AbstractAmylin receptor agonism safely benefit diabetic patients, reducing the insulin requirements and glycemic excursions. Pramlintide is the triple proline human amylin analogue first used as injectable drug, but lacking physico‐chemical compatibility when co‐formulated with insulin. Here, we report the design and characterization of polymeric microparticles for oral delivery of pramlintide. Eudragit S100, a gastric‐resistant polymer, was used in preparation of pramlintide‐loaded spherical microcapsules by double emulsion and solvent evaporation technique, with approximately 66 μm ± 11 particle size, with 83.2% ± 2.7 efficiency for pramlintide entrapment and 67.6% ± 2.1 yield. Intra‐venous pramlintide free in solution showed a plasmatic half‐life of 6.8 min in mice. In contrast, oral delivery of acid‐resistant pramlintide‐loaded microparticles in mice showed a protracted release for 120 min compared to 30 min obtained for pramlintide in solution. Our data provide evidences for the potential use of the oral route in the therapeutic development of pramlintide formulations.

Triglycerides Stabilize Water/Organic Interfaces of Changing Area via Conformational Flexibility.

The role of triglycerides (TGs) in both natural and synthetic biological membranes has long been the subject of study, involving metabolism, disease, and colloidal synthesis. TGs have been found to be critical components for successful liposomal encapsulation via a water/oil/water double emulsion, which this work endeavors to explain. TGs can occupy multiple positions in biological membranes. The glycerol backbone can reside at the water/organic interface, adjacent to phospholipid headgroups ("m" conformation), typically with relatively low (<3%) solubility. The glycerol backbone can also occupy hydrophobic regions, where it is isolated from water ("h" or "oil" conformation). This can occur in either midmembrane positions or phospholipid-coated lipid droplets (LDs). These conformations can be distinguished using 13C-nuclear magnetic resonance spectroscopy (NMR), which determines the degree of hydration of the TG backbone. Using this method, it was revealed that TGs transition from "m" to "h" conformation as the organic solvent is removed via evaporation. A new transitional TG backbone position has been identified with a level of hydration between "m" and "h". These results suggest that TGs can temporarily coat and stabilize the large water/organic interfaces present after emulsification. As the organic solvent is removed and interfaces shrink, the TGs recede into midmembrane spaces or bud off into LDs, which are confirmed via transmission electron microscopy (TEM) and can be removed via centrifugation. Encapsulation efficiency is found to be inversely related to both the saturation and length of the TG acyl chains, indicating that membrane fluidization is a key property arising from the presence of TGs. Beyond clarification of a mechanism for high-efficiency liposomal encapsulation, these results implicate TGs as components that are able to stabilize biological membrane transitions involving a changing interfacial area and curvature. This role for TGs may be of use in the formulation of drug delivery systems as well as in the investigation of membrane transitions in life sciences.

Double W/O/W emulsion is effective for carrying calcium and vitamin D

A double emulsion is a promising system to facilitate the fortification process of nutrients such as calcium and vitamin D, as it protects vitamin D from oxidation and calcium from interactions with food proteins. The aim of this work was to produce Wi/O/We type double emulsions carrying vitamin D and calcium. The influence of the proportion of aqueous phase Wi/We (10/60, 15/55 and 20/70) and the concentration of polyglycerol polyricinoleate (PGPR) emulsifier (2.0, 2.5 and 3.0% w/w) on the kinetic stability of the emulsions over 13 days of storage was evaluated. For this, the following were analyzed: zeta potential, rheological properties (flow curve and viscoelasticity), entrapment efficiency (EE), and kinetic stability (KS) of calcium localization, microstructure, and macroscopic stability of the W/O/W emulsions, as well as the interfacial tension of the primary emulsions (Wi/O). The highest EE and KS of calcium localization were observed in treatments with smaller proportions of internal aqueous phase, regardless of the PGPR concentration. Therefore, an aqueous phase proportion of 10/60 combined with 2% PGPR is recommended.

Fabrication and characterization of W1/O/W2 double emulsions stabilized with Pleurotus geesteranus protein particles via one-step emulsification

In this study, Pleurotus geesteranus protein isolate (PPI) with low solubility in water was fabricated into nanoparticle (PPIP) that can be uniformly dispersed in pH 7.0 aqueous solution using pH cycle method. PPIP with a zeta potential of −19.21 mV had a mean size of 250.53 nm and two main peaks in particle size distribution profile. This was consistent with the TEM results, which existed both as individual particles and as particle aggregates. The main force responsible for maintaining the structure of protein particles was hydrogen bonding. Interestingly, these protein particles were successfully utilized to fabricate W1/O/W2 double emulsions using one-step homogenous emulsification, and the formation and properties of PPIP-stabilized W1/O/W2 double emulsions were significantly influenced by the protein particle concentration, oil content, and salt concentration in W2 continuous phase. Specifically, higher particle concentration and salt concentration caused a reduction in the number of W1/O droplets and the size of oil droplets. Conversely, an increase in oil content increased the number of W1/O droplets primarily due to the augmentation in the size of oil droplets. The gel strength of double emulsions was enhanced with particle concentration and oil content, as this led to the formation of stronger particle networks and droplet networks. While an opposite phenomenon was found in increasing salt concentration in W2 continuous phase, possibly resulting from the disruption of the ordered gel network. These findings not only provide new food-grade emulsifiers for W1/O/W2 double emulsions, but also broaden the application of edible mushroom proteins in food industry.

Numerical investigation of double emulsion formation in non-Newtonian fluids using double co-flow geometry

This paper uses the Volume of Fluid (VOF) method to simulate a double Co-Flow microfluidic device that can produce double emulsions in both Newtonian (water) and non-Newtonian fluids. The simulation is 2D axisymmetric and involves three phases. A model is evaluated in this study to examine how the size and double emulsion’s generation rate are impacted by factors such as phase velocity, viscosities, interfacial tension, and the rheological properties of non-Newtonian fluids. The model predicted the process of emulsification successfully in dripping and jetting regimes and predicted the impacts of phase velocity on the dimension and frequency of compound droplets. Increasing the flow rate of the inner phase causes the inner droplets to grow, while the outer droplet dimensions remain mostly unchanged. Vice versa, an increase in outer phase flow rate reduces compound droplet size. However, when the middle phase's flow rate is enhanced, the size of detached droplets in the inner and outer phases undergoes opposite changes, i.e., decreasing and increasing, respectively. The results showed that in non-Newtonian fluids, smaller droplets are formed compared to water, and the diameter of the double emulsions formed decreases with the rise in the viscosity at zero shear rate of the non-Newtonian fluid.

Encapsulation of Lactobacillus rhamnosus GG in double emulsions: Role of prebiotics in improving probiotics survival during spray drying and storage

The protective effect of solid fat on probiotics to reduce heat damage during spray drying was revealed in previous study. However, the direct dispersion of fresh cells in the thermo-protectants did not encapsulate the probiotics in the oil phase, but dispersed in the water phase. Therefore, this study aims to improve the protective effect of solid fat to probiotics during spray drying by encapsulating Lactobacillus rhamnosus GG (LGG) in double emulsion (W/O/W) containing solid fat. In addition, various prebiotics were added in W/O/W as wall materials, and their ability of improving the vitality of probiotics was evaluated by combining spray drying and re-culture. The results of fluorescence microscope and scanning electron microscope demonstrated the successful encapsulation of LGG in double emulsions during spray drying, which increased the survival rate from 43.23% to 65.16% while improved the integrity of the subcellular structure. In terms of prebiotic effects, the microcapsules of W/O/W + inulin showed the lowest water activity and higher glass transition temperature, leading to the best survival of LGG during storage in all tested formulations, while W/O/W + FOS had the best proliferation-promoting in re-culture due to the fact that LGG consumed more FOS than other prebiotics during re-culture. Therefore, the current study has provided valuable information for the selection of carriers and wall materials in improving the viability of probiotics during spray drying.

Numerical investigation of the effect of microfluidic flow parameters and physical properties on double emulsion droplet forming

Numerical investigation of the effect of microfluidic flow parameters and physical properties on double emulsion droplet forming

Tailoring an egg white protein double network emulsion gel as a novel fat substitute for improving freeze-thaw stability of minced meat gel

This work aimed to investigate the effect of double network emulsion gel (DNEG) as a substitute for pork back fat (PBF) on the freeze-thaw stability of minced meat gel (MMG). We used slow acidification with glucono-δ-lactone (GDL) to induce egg white protein (EWP) gelation, while CaCO3 was affected by acidification to release Ca2+ to cross-link sodium alginate (SA), resulting in the gradual formation of DNEG networks. The MMG prepared using DNEG substitute for PBF had fine hardness and color after 5 freeze-thaw cycles (FTCs). This was due to the excellent plasticity of DNEG, which made it more capable of filling the voids of minced meat products, thus reducing the space for ice crystal growth. As a result, MMG prepared with DNEG could pass through the maximum ice crystal formation zone faster and avoid damage due to the formation of larger ice crystals. Notably, DNEG provided a barrier for the migration of immobilized water to bulk water in the sample. After several freeze-thaw treatments, the water holding capacity of samples prepared with DNEG decreased significantly slower, which slowed down the oxidation and decomposition of meat proteins. In summary, this study revealed the role of fat substitute DNEG as a favorable filling material for improving the freeze-thaw stability of minced meat products, and provided a technical reference for the development of healthy and storable meat products.

Insight on the interaction between soybean protein isolate and ionic/non-ionic polysaccharides: Structural analysis, oil-water interface properties investigation and double emulsion formation

In this study, hydroxypropyl methylcellulose (HPMC) and xanthan gum (XG) were utilized to enhance the interfacial activity of soybean protein isolate (SPI) by forming complexes with SPI, respectively. Meanwhile, SPI-HPMC and SPI-XG were used to construct a double emulsion to investigate the effects of the interaction of ionic/nonionic polysaccharides with SPI on the performances of the double emulsion. The results of multispectral analyses showed that both HPMC and XG induced structural changes in SPI, thereby exposing a large number of hydrophobic groups. Moreover, molecular simulation results showed high stability of the complexes formed by SPI with HPMC and XG. The results of molecular simulations showed that the complexes formed by SPI with HPMC and XG were highly stable. Furthermore, the ability of SPI to reduce interfacial tension at the oil-water interface and its emulsifying ability was enhanced by the formation of complexes with polysaccharides, which also improved the physicochemical properties of the double emulsion stabilized by the SPI-polysaccharide complex. When the phase ratio (W1/O:W2) was 4:6 and the polysaccharide addition was 0.4%, the double emulsion showed the smallest particle size, the highest encapsulation efficiency and the best stability. Th in vitro digestion models demonstrated that the SPI-XG double emulsion could effectively protect the encapsulated bioactives during the digestion process and increase their bioaccessibility to 70.86%. In summary, this study was beneficial in corroborating the ability of ionic/non-ionic polysaccharides in improving the interfacial properties of SPI and improving the performance of the double emulsion.

Double Emulsions Stabilized by PGPR and Arabic Gum as Capsules: The Surprising Stabilizing Role of Inner Droplets.

The encapsulation efficiency and stability over time of either vitamin B12, a model hydrophilic drug, or an aqueous suspension of Cydia pomonella granulovirus (CpGV), which is a biopesticide, using a water-in-sunflower oil-in-water (W1/O/W2) double emulsion, are studied. Two antagonistic stabilizers are used to prepare the double emulsion: the mainly lipophilic polyglycerol polyricinoleate (PGPR) and the mainly hydrophilic polysaccharide Arabic gum (AG). Combining ultraviolet-visible (UV-visible) titration, rheology, and oil globule size measurement allows assessing drug release, emulsion elasticity, and globule evolution as a function of time. A stability diagram is plotted as a function of two determining parameters: the nonadsorbed PGPR concentration in the oil and the inner water droplet fraction. To understand the presence of the nonstability domains, the influence of the two identified parameters on the outermost interfacial tension is examined. Surprisingly, the inner water drop volume fraction exhibits a stabilizing phenomenon that is discussed in terms of interfacial shielding to PGPR adsorption.

Aerosolizable Pyrazinamide-Loaded Biodegradable Nanoparticles for the Management of Pulmonary Tuberculosis.

Background: Pyrazinamide is a Biopharmaceutical Classification System class III antibiotic indicated for active tuberculosis. Methods: In the present work, pyrazinamide-loaded biodegradable polymeric nanoparticles (PNPs) based dry powder inhaler were developed using the double emulsion solvent evaporation technique and optimized using design of experiments to provide direct pulmonary administration with minimal side effects. Batches were characterized for various physicochemical and aerosol performance properties. Results: Optimized batch exhibited particle size of 284.5 nm, % entrapment efficiency of 71.82%, polydispersibility index of 0.487, zeta potential of -17.23 mV, and in vitro drug release at 4 hours of 79.01%. Spray-dried PNPs were evaluated for drug content, in vitro drug release, and kinetics. The particle mass median aerodynamic diameter was within the alveolar region's range (2.910 μm). In the trachea and lung, there was a 2.5- and 1.2-fold increase in in vivo deposition with respect to pure drug deposition, respectively. In vitro drug uptake findings showed that alveolar macrophages with pyrazinamide PNPs had a considerably higher drug concentration. Furthermore, accelerated stability studies were carried out for the optimized batch. Results indicated no significant change in the evaluation parameters, which showed stability of the formulation for at least a 6-month period. Conclusion: PNPs prepared using biodegradable polymers exhibited efficient pulmonary drug delivery with decent stability.

Ultrasound-assisted extraction of anthocyanin from black rice bran and its encapsulation by complex coacervation

The present work was planned to optimize extraction process of phenolics, flavonoids, monomeric anthocyanin and antioxidants from black rice bran using Ultrasound-assisted extraction and finally utilize it for encapsulation using double emulsion coacervation process. Response surface methodology (RSM) was employed for optimization of extraction process. Acidified ethanol (1 M HCl) was used as extraction solvent and ultrasound power (W) and extraction time (min) were used as independent variables. Face centered composite design (FCCD) data was successfully opted and developed a 2nd order polynomial equation with R2 value of 0.94 for total phenolic content (TPC), 0.95 for total flavonoid content (TFC), 0.87 for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 0.98 for total anthocyanin content (ANCs) respectively. Kinetic model study for extraction of anthocyanin was compared to conventional extraction process. Characterization of the extracts was performed using high pressure liquid chromatography analysis (HPLC). Cyanidin-3-glucoside is the predominated anthocyanin found as compared to peonidin-3-D-glucoside. Finally, coacervated microcapsules were developed using anthocyanin extract as core solution and gelatin and acacia gum as wall materials. Characterization of the microcapsules in terms of moisture content, hygroscopicity, solubility, encapsulation efficiency and surface morphology were evaluated. The result thus obtained shows that potential anthocyanin content from black rice bran can be utilized as food ingredients for various food application and formulation of functional food.

Double emulsion (W/O/W) microcapsule preparation of novel bacteriocin lactococcin036019 with synergistic compound vitamin C prolongs the antibacterial activity in food matrix

Application of bacteriocins in food preservation encounters the issue of activity impairment. This study intends to find a comprehensive solution to the enhancement of bacteriocin activity. Firstly, several food matrices were found to significantly reduce the antibacterial activity of bacteriocin lactococcin036019. Subsequently, vitamin C and carvacrol were both found to display a synergistic effect with bacteriocin against Staphylococcus aureus. Thereafter, double emulsion containing lactococcin036019 and vitamin C was successfully prepared. Spray drying of double emulsion with lactococcin036019 and vitamin C resulted in microcapsule powder with the particle size and entrapment efficiency of 9.10 μm and 56.18%, respectively. This microcapsule powder reduced S. aureus number by around 5 lg cfu/mL at 24 h and displayed continuous antibacterial activity in soymilk. Besides, the microcapsule powder with bacteriocin and vitamin C showed remarkable stability during storage. The double emulsion microcapsules prepared in this study demonstrate great potential in long-term preservation of food.