Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness

Sodium (salt) was encapsulated within the inner water phase of w₁/o/w₂ food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0-3%) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.

Development of ionophore-based nanosphere emulsion incorporating ion-exchanger for complexometric titration of thiocyanate anion

Ionophore-based ion-exchange nanosphere emulsion was prepared and tested for the determination of thiocyanate. The emulsified nanosphere contained the cationic additive tridodecylmethyl ammonium chloride (TDMAC), the plasticizer, and the ionophore Mn(III)-salophen or Mn(III)-salen. This emulsion was used as titrating agent for thiocyanate complexation with ionophores, which could be transduced using an ion-selective electrode (ISE) as an indicator electrode for the end point detection. The method showed no need for pH control and reliable selectivity, as thiocyanate could be determined in presence of other interfering ions with high accuracy. As well, the emulsion was stable and could be used for approximately couple of weeks. The developed emulsion could be used for the determination of thiocyanate in human saliva with standard deviation <4%. In sum, the proposed method could be used as an alternative for the argentometric titration and would open new avenues for the determination of neutral, anionic, and cationic species without necessity for water soluble ligands or pH control.

The optimization of technological processes, stability and microbiological evaluation of innovative natural ingredients-based multiple emulsion

For the last couple of decades, multiple emulsions were prepared either by the re-emulsification of primary emulsion or they were produced by an emulsion inversion and their technological peculiarities were widely investigated. The aim of our study was to investigate and determine the optimal technological parameters of innovative multiple emulsion, prepared directly-by addition of ethanolic rosemary extract in the presence of polymeric emulsifier-and evaluate its stability by experimental surface response design approach. The results revealed that simplified W/O/W emulsification process is stirring time and stirring speed sensitive: the change of stirring time from 5 to 15 min at 600 rpm resulted in increased viscosity (from 1705.6 ± 62.2 to 3364.1 ± 112.5 mPA/s) and smaller oil droplet size (from 33.09 ± 1.51 to 17.81 ± 0.78 μm), though the conductivity increased from 800 ± 2 to 882 ± 2 μS/cm (p < .05). The second mixing stage (1000 rpm) had a negative effect on the conductivity of W/O/W emulsion because of the inner aqueous phase encapsulation efficiency. Ethanolic rosemary extract was used as multifunctional agent: not only to form multiple emulsion but also to preserve it; microbiological assay confirmed its effectiveness. A stable W/O/W type drug delivery system was successfully created without additional technological stages, phase inversion or surfactants.

Technological and sensorial role of yeast β-glucan in meat batter reformulations

This study shows that apart from acting as nutritional value improver, yeast β-glucan can be successfully used to reformulate meat products. When added to meat batters, yeast derived ingredients containing β-glucans (GOLDCELL^® IY B and GOLDCELL^® BETA GLUCAN) improved the emulsifying capacity (up to 5 increments), the water holding capacity (up to 8 increments) as well as the emulsion stability. A decrease in total fluid release up to 4.30% and 3.99%, respectively with GOLDCELL^® IY B and GOLDCELL^® BETA GLUCAN respectively, at 1.5% addition level was observed. A significant decrease in hardness and fracturability values was also observed, while maintaining the structural cohesiveness of the samples, in part due to the increase in humidity content. A maximum level of 3% ingredient mixture can be added to meat batter formulations without significant impact on sensory characteristics. Adding yeast β-glucan to meat batters can allow food to decrease the NaCl and polyphosphate content in meat products.

Gellified Emulsion of Ofloxacin for Transdermal Drug Delivery System

Purpose: Ofloxacin is a fluoroquinolone with broad-spectrum antibacterial action, used in treatment of systemic and local infections. Ofloxacin is BCS class II drug having low solubility, high permeability with short half-life. The present work was aimed to design, develop and optimize gellified emulsion of Ofloxacin to provide site targeted drug delivery. Transdermal drug delivery will enhance the bioavailability of the drug giving controlled drug release.

Methods: Transdermal drug delivery system was designed with gelling agent (Carbopol 940 and HPMC K100M), oil phase (oleic acid) and emulsifying agent (Tween 80: Span 80). Effect of concentration of gelling agent on release of drug from transdermal delivery was studied by 3² factorial design. Emulgel was evaluated for physical appearance, pH, drug content, viscosity, spreadability, antimicrobial activity, in- vitro diffusion study and ex-vivo diffusion study.

Results: FE-SEM study of the emulsion batch B5 has revealed formation of emulsion globules of approximately size 6-8 µm with -11.2 mV zeta potential showing good stability for the emulsion. Carbopol 940 had shown greater linear effect on drug release and viscosity of the formulations due to its high degree of gelling. In-vitro diffusion study through egg membrane had shown 88.58±1.82 % drug release for optimized batch F4. Ex-vivo diffusion study through goat skin indicated 76.68 ± 2.52% drug release.

Conclusion: Controlled release Ofloxacin emulgel exhibiting good in-vitro and ex-vivo drug release proving good antimicrobial property was formulated.

Lipophilic salts of poorly soluble compounds to enable high-dose lipidic SEDDS formulations in drug discovery

Self-emulsifying drug delivery systems (SEDDS) have been used to solubilize poorly water-soluble drugs to improve exposure in high-dose pharmacokinetic (PK) and toxicokinetic (TK) studies. However, the absorbable dose is often limited by drug solubility in the lipidic SEDDS vehicle. This study focuses on increasing solubility and drug loading of ionizable drugs in SEDDS vehicles using lipophilic counterions to prepare lipophilic salts of drugs. SEDDS formulations of two lipophilic salts-atazanavir-2-naphthalene sulfonic acid (ATV-2-NSA) and atazanavir-dioctyl sulfosuccinic acid (ATV-Doc)-were characterized and their performance compared to atazanavir (ATV) free base formulated as an aqueous crystalline suspension, an organic solution, and a SEDDS suspension, using in vitro, in vivo, and in silico methods. ATV-2-NSA exhibited ∼6-fold increased solubility in a SEDDS vehicle, allowing emulsion dosing at 12mg/mL. In rat PK studies at 60mg/kg, the ATV-2-NSA SEDDS emulsion had comparable exposure to the free-base solution, but with less variability, and had better exposure at high dose than aqueous suspensions of ATV free base. Trends in dose-dependent exposure for various formulations were consistent with GastroPlus™ modeling. Results suggest use of lipophilic salts is a valuable approach for delivering poorly soluble compounds at high doses in Discovery.

Intravenous Delivery of Xenon Incorporated in Thermosensitive Nano-Emulsions for Anesthesia

Xenon anesthesia has several advantages over conventional anesthetics, however, it has not been widely used in clinical sites, since the cost and minimum alveolar concentration were higher than conventional inhalational anesthetics. The purpose of this study was to develop an optimum vehicle for stable intravenous delivery of xenon with sufficient concentration. Thermosensitive lipid based nano-emulsions (TS-LE) were prepared by blending medium chain triglyceride, polyethylene glycol-15-hydroxystearate, D-α tocopherol polyethylene glycol succinate and Poloxamer 188. Three folds higher xenon was loaded in TS-LE when it was prepared under 5.5 atm of xenon pressure compared to that under 1 atm of xenon pressure at 22 °C (11.4±0.7 vs. 3.82±0.34 mg/ml). Poloxamer 188 conferred thermosensitive viscosity and outer rigid structure on TS-LE, and the properties led to the enhanced stability of xenon compared to usual lipid emulsion. Induction of anesthesia was investigated by monitoring loss of forepaw righting reflex (LORR) in rats. The ED50 for LORR was 131.9 mg/kg and the anesthesia was maintained for 65.3±7.1 sec at a dose of 179 mg/kg in rats. When it is considered that TS-LE stably loads enough concentration of xenon for the induction of therapeutically sufficient anesthesia, TS-LE may be regarded as a promising candidate for intravenous xenon delivery.

Turning hydrophilic bacteria into biorenewable hydrophobic material with potential antimicrobial activity via interaction with chitosan

Alteration of a bacteriocin-producing hydrophilic bacterium, Lactococcus lactis IO-1, into a hydrophobic material with potential antimicrobial activity using chitosan was investigated and compared with five other bacterial species with industrial importance. The negatively charged bacterial cells were neutralized by positively charged chitosan, resulting in a significant increase in the hydrophobicity of the bacterial cell surface. The largest Gram-positive B. megaterium ATCC 14581 showed a moderate response to chitosan while the smaller E. coli DH5α, L. lactis IO-1 and P. putida F1 exhibited a significant response to an increase in chitosan concentration. Because L. lactis IO-1 is a good source for natural peptide lantibiotic that is highly effective against several strains of food spoilage organisms and pathogens, hydrophobic material derived from L. lactis IO-1 and chitosan is a promising novel material with antimicrobial activity for the food and pharmaceutical industries.

Cyclosporine A delivery to the eye: A comprehensive review of academic and industrial efforts

Local ocular delivery of cyclosporine A (CsA) is the preferred method for CsA delivery as a treatment for ocular inflammatory diseases such as uveitis, corneal healing, vernal keratoconjunctivitis and dry eye disease. However, due to the large molecular weight and hydrophobic nature of CsA and the natural protective mechanisms of the eye, achieving therapeutic levels of CsA in ocular tissues can be difficult. This review gives a comprehensive overview of the current products available to clinicians as well as emerging drug delivery solutions that have been developed at both the academic and industry levels.

Synthesis and characterization of magnetic chitosan microspheres as low-density and low-biotoxicity adsorbents for lake restoration

We propose a novel magnetic adsorbent for optimal Phosphorus (P) removal from the upper sediment layers. For this aim, magnetic chitosan microparticles were prepared using a reverse-phase suspension cross-linking technique. The resulting particles and suspensions were characterized using scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, magnetometry, thermogravimetric analysis, electrophoretic mobility and turbidity measurements. The hybrids are multicore particles consisting of well dispersed magnetite nanoparticles (approx. 10% w/w) homogeneously distributed within the biopolymer matrix. These microparticles can be easily separated from the water column and sediment using magnetic field gradients. Their P adsorption capacity is evaluated in batch conditions resulting in a maximum P adsorption capacity of M_L = 4.84 mg g^-1 at pH = 7. We demonstrate that these particles are excellent candidates to remove P from water column and also P mobile from the upper sediment layers due to two main reasons: they sediment slower and present lower potential toxicity (due to a their larger size) than conventional iron/iron oxide microparticles previously proposed for lake restoration.

Effect of ultrasonic frequency on separation of water from heavy crude oil emulsion using ultrasonic baths

In this work, a comprehensive study was performed for the evaluation of ultrasound (US) frequency for demulsification of crude oil emulsions. Experiments were performed using ultrasonic baths operating at the following frequencies: 25, 35, 45, 130, 582, 862 and 1146kHz. Synthetic water-in-oil emulsions with 12%, 35% and 50% of water and medians of droplet size distribution (DSD, D(0.5)) of 5, 10 and 25μm were prepared using a heavy crude oil (API density of 19). Crude oil demulsification was achieved at frequencies in the range of 25-45kHz for all tested emulsions. When frequencies higher than 45kHz were applied, no changes in the characteristics of the crude oil emulsions were observed. Demulsification efficiencies of about 65% were achieved at a frequency of 45kHz after 15min of US application (emulsions with original water content of 50% and D(0.5)=10μm). An important aspect is that no addition of chemical demulsifiers was performed, and the demulsification efficiency was considered high, taking into account that the results were obtained using a non-conventional crude oil. Contrary to the normal application of low-frequency US that has been used for emulsification, the proposed approach seems to be a promising technology for water removal from crude oil emulsions.

Manufacture of Oil-in-Water Emulsion Adjuvants

Emulsion adjuvants for human vaccines have evolved gradually over the last century. Current formulations are the result of many refinements to their composition and manufacturing, as well as optimization for safety and efficacy. Squalene has emerged as being particularly suitable for the manufacturing of safe oil-in-water (O/W) adjuvants for parenteral applications due to its biocompatibility and ability to be metabolized. Emulsion particle size has been identified as an important parameter affecting the pharmaceutical performance of O/W emulsion adjuvants. Submicronic emulsions with sizes in the 80-200 nm range are preferred for potency, manufacturing consistency, and stability reasons. Two manufacturing processes, high pressure homogenization (HPH or microfluidization) and a phase inversion temperature method (PIT), are described to yield such fine and long-term stable emulsion adjuvants.

Physical stability of N,N-dimethyldecanamide/α-pinene-in-water emulsions as influenced by surfactant concentration

In recent years, interest in submicron emulsions has increased due to their high stability and potential applications in the encapsulation and release of active ingredients in many industrial fields, such as the food industry, pharmaceuticals or agrochemicals. Furthermore, the social demand for eco-friendly solutions to replace hazardous solvents in many dispersion formulations has steadily risen. In this study, the influence of surfactant concentration on the formation and physical stability of submicron oil-in-water emulsions using a high-pressure dual-channel homogenizer (microfluidizer) has been investigated. The formulation involved the use of a blend of two green solvents (N,N-dimethyldecanamide and α-pinene) as dispersed phase and a nonionic polyoxyethylene glycerol ester derived from coconut oil as emulsifier (Levenol^® C-201), which enjoys a European eco-label. Therefore, these emulsions may find applications as matrices for agrochemicals. Physical stability and rheological properties of the emulsions studied showed an important dependence on the eco-friendly surfactant concentration. The lowest surfactant concentration (1wt%) yielded the onset of a creaming process after a short aging time and was not enough to avoid recoalescence during emulsification. On the other hand, the higher surfactant concentrations (4-5wt%) resulted in depletion flocculation, which in turn triggered emulsion destabilization by coalescence. The optimum physical stability was exhibited by emulsions containing intermediate surfactant concentrations (2-3wt%) since coalescence was hardly significant and the onset of a weak creaming destabilization process was substantially delayed.

Lipid Therapy for Intoxications

This review discusses the use of intravenous lipid emulsion (ILE) in the treatment of intoxications with lipophilic agents in veterinary medicine. Despite growing scientific evidence that ILE has merit in the treatment of certain poisonings, there is still uncertainty on the optimal composition of the lipid emulsion, the dosing, the mechanism of action, and the efficacy. Therefore, a critical view of the clinician on the applicability of this modality in intoxications is still warranted. The use of ILE therapy is advocated as an antidote in cases of intoxications with some lipophilic substances.

Synergistic performance of lecithin and glycerol monostearate in oil/water emulsions

The effects of the combination of two low-molecular weight emulsifiers (lecithin and glycerol-monostearate (GMS)) on the stability, the dynamic interfacial properties and rheology of emulsions have been studied. Different lecithin/GMS ratios were tested in order to assess their impact in the formation and stabilization of oil in water emulsions. The combination of the two surfactants showed a synergistic behaviour, mainly when combined at the same ratio. The dynamic film properties and ζ-potential showed that lecithin dominated the surface of oil droplets, providing stability to the emulsions against flocculation and coalescence, while allowing the formation of small oil droplets. At long times of adsorption, all of the mixtures showed similar interfacial activity. However, higher values of interfacial pressure at the initial times were reached when lecithin and GMS were at the same ratio. Interfacial viscoelasticity and viscosity of mixed films were also similar to that of lecithin alone. On the other hand, emulsions viscosity was dominated by GMS. The synergistic performance of lecithin-GMS blends as stabilizers of oil/water emulsions is attributed to their interaction both in the bulk and at the interface.

In vitro and in vivo assessment of controlled release and degradation of acoustically responsive scaffolds

Spatiotemporally controlled release of growth factors (GFs) is critical for regenerative processes such as angiogenesis. A common strategy is to encapsulate the GF within hydrogels, with release being controlled via diffusion and/or gel degradation (i.e., hydrolysis and/or proteolysis). However, simple encapsulation strategies do not provide spatial or temporal control of GF delivery, especially non-invasive, on-demand controlled release post implantation. We previously demonstrated that fibrin hydrogels, which are widely used in tissue engineering and GF delivery applications, can be doped with perfluorocarbon emulsion, thus yielding an acoustically responsive scaffold (ARS) that can be modulated with focused ultrasound, specifically via a mechanism termed acoustic droplet vaporization. This study investigates the impact of ARS and ultrasound properties on controlled release of a surrogate payload (i.e., fluorescently-labeled dextran) and fibrin degradation in vitro and in vivo. Ultrasound exposure (2.5MHz, peak rarefactional pressure: 8MPa, spatial peak time average intensity: 86.4mW/cm²), generated up to 7.7 and 21.7-fold increases in dextran release from the ARSs in vitro and in vivo, respectively. Ultrasound also induced morphological changes in the ARS. Surprisingly, up to 2.9-fold greater blood vessel density was observed in ARSs compared to fibrin when implanted subcutaneously, even without delivery of pro-angiogenic GFs. The results demonstrate the potential utility of ARSs in generating controlled release for tissue regeneration.

STATEMENT OF SIGNIFICANCE

Simple encapsulation of a molecular payload within a conventional hydrogel scaffold does not provide spatial or temporal control of payload release. Yet, spatiotemporally controlled release of bioactive payloads is critical for tissue regeneration, which often utilizes hydrogel scaffolds to facilitate processes such as angiogenesis. This work investigates the design and performance (both in vitro and in vivo) of hydrogel scaffolds where release of a fluorescent payload is non-invasively and spatiotemporally-controlled using focused ultrasound. We also quantitatively characterize the degradation and vascularization of the scaffolds. Our results may be of interest to groups working on controlled release strategies for implants, especially within the field of tissue engineering.

Investigation on environmental factors of waste plastics into oil and its emulsion to control the emission in DI diesel engine

Rapid depletion of conventional fossil fuel resources, their rising prices and environmental issues are the major concern of alternative fuels. On the other hand waste plastics cause a very serious environmental dispute because of their disposal problems. Waste plastics are one of the promising factors for fuel production because of their high heat of combustion and their increasing availability in local communities. In this study, waste plastic oil (WPO) is tested in DI diesel engine to evaluate its performance and emission characteristics. Results showed that oxides of nitrogen (NO_x) emission get increased with WPO when compared to diesel oil. Further, the three phase (O/W/O) plastic oil emulsion is prepared with an aid of ultrasonicater according to the %v (10, 20 & 30). Results expose that brake thermal efficiency (BTE) is found to be increased. NO_x and smoke emissions were reduced up to 247ppm and 41% respectively, when compared to diesel at full load condition with use of 30% emulsified WPO.

Antimicrobial effect of emulsion-encapsulated isoeugenol against biofilms of food pathogens and spoilage bacteria

Food-related biofilms can cause food-borne illnesses and spoilage, both of which are problems on a global level. Essential oils are compounds derived from plant material that have a potential to be used in natural food preservation in the future since they are natural antimicrobials. Bacterial biofilms are particularly resilient towards biocides, and preservatives that effectively eradicate biofilms are therefore needed. In this study, we test the antibacterial properties of emulsion-encapsulated and unencapsulated isoeugenol against biofilms of Lis. monocytogenes, S. aureus, P. fluorescens and Leu. mesenteroides in tryptic soy broth and carrot juice. We show that emulsion encapsulation enhances the antimicrobial properties of isoeugenol against biofilms in media but not in carrot juice. Some of the isoeugenol emulsions were coated with chitosan, and treatment of biofilms with these emulsions disrupted the biofilm structure. Furthermore, we show that addition of the surfactant Tween 80, which is commonly used to disperse oils in food, hampers the antibacterial properties of isoeugenol. This finding highlights that common food additives, such as surfactants, may have an adverse effect on the antibacterial activity of preservatives. Isoeugenol is a promising candidate as a future food preservative because it works almost equally well against planktonic bacteria and biofilms. Emulsion encapsulation has potential benefits for the efficacy of isoeugenol, but the effect of encapsulation depends on the properties of food matrix in which isoeugenol is to be applied.

Tunable volatile release from organogel-emulsions based on the self-assembly of β-sitosterol and γ-oryzanol

A current challenge in the area of food emulsion is the design of microstructure that provides controlled release of volatile compounds during storage and consumption. Here, a new strategy addressed this problem at the fundamental level by describing the design of organogel-based emulsion from the self-assembly of β-sitosterol and γ-oryzanol that are capable of tuning volatile release. The results showed that the release rate (v₀), maximum headspace concentrations (C_max) and partition coefficients (k_a/e) above structured emulsions were significantly lower than unstructured emulsions and controlled release doing undergo tunable though the self-assembled interface and core fine microstructure from internal phase under dynamic and static condition. This result provides an understanding of how emulsions can behave as delivery system to better design novel food products with enhanced sensorial and nutritional attributes.

A facile and green emulsion casting method to prepare chitin nanocrystal reinforced citrate-based bioelastomer

Chitin nanocrystal (ChiNC) is a promising reinforcing nanofiller for biomedical polymers. However, its self-aggregation characteristics caused processing difficulty in developing ChiNC-based nanocomposites. Herein, a new degradable crosslinked bioelastomer, designated as poly(1,8-octanediol-co-Pluronic F127 citrate) (POFC) was synthesized by melt polycondensation of citric acid, 1,8-octanediol, and Pluronic F127. In comparison to poly(1,8-octanediol citrate) (POC), POFC pre-polymer exhibited self-emulsifying property. Once ChiNC was introduced into the emulsion, a ChiNC stabilized Pickering emulsion was formed. Coupled with a facile green emulsion casting/evaporation method, the ChiNC ultimately reinforced ChiNC/POFC nanocomposite elastomer was fabricated. The presence of F127 segments endowed POFC with better hydrophilicity and shorter degradation time relative to POC. The incorporation of ChiNC into POFC network led to highly increased tensile modulus and strength. In vitro cytotoxicity tests indicated that the ChiNC/POFC elastomer nanocomposite had a good cytocompatibility and it appeared as a potential biomaterial for tissue engineering application.

Control of drop shape transformations in cooled emulsions

The general mechanisms of structure and form generation are the keys to understanding the fundamental processes of morphogenesis in living and non-living systems. In our recent study (Denkov et al., Nature 528 (2015) 392) we showed that micrometer sized n-alkane drops, dispersed in aqueous surfactant solutions, can break symmetry upon cooling and "self-shape" into a series of geometric shapes with complex internal structure. This phenomenon is important in two contexts, as it provides: (a) new, highly efficient bottom-up approach for producing particles with complex shapes, and (b) remarkably simple system, from the viewpoint of its chemical composition, which exhibits the basic processes of structure and shape transformations, reminiscent of morphogenesis events in living organisms. In the current study, we show for the first time that drops of other chemical substances, such as long-chain alcohols, triglycerides, alkyl cyclohexanes, and linear alkenes, can also evolve spontaneously into similar non-spherical shapes. We demonstrate that the main factors which control the drop "self-shaping", are the surfactant type and chain length, cooling rate, and initial drop size. The studied surfactants are classified into four distinct groups, with respect to their effect on the "self-shaping" phenomenon. Coherent explanations of the main experimental trends are proposed. The obtained results open new prospects for fundamental and applied research in several fields, as they demonstrate that: (1) very simple chemical systems may show complex structure and shape shifts, similar to those observed in living organisms; (2) the molecular self-assembly in frustrated confinement may result in complex events, governed by the laws of elasto-capillarity and tensegrity; (3) the surfactant type and cooling rate could be used to obtain micro-particles with desired shapes and aspect ratios; and (4) the systems studied serve as a powerful toolbox to investigate systematically these phenomena.

Marine fungi as source of new hydrophobins

Hydrophobins have been described as the most powerful surface-active proteins known. They are produced by filamentous fungi and exhibit a distinct amphiphilic structure determining their self-assembly at hydrophilic-hydrophobic interfaces and surfactant properties which have been demonstrated to be useful for several biotechnological applications. The marine environment represents a vast natural resource of new molecules produced by organisms growing in various stressful conditions. This study was focused on the screening of 100 marine fungi from Mycoteca Universitatis Taurinensis (MUT) for the identification of new hydrophobins. Four different methods were set up to extract hydrophobins of class I and II, from the mycelium or the culture broth of fungi. Six fungi were selected as the best producers of hydrophobins endowed with different characteristics. Their ability to form stable amphiphilic films and their emulsification capacity in the presence of olive oil was evaluated.

Lipid based delivery and immuno-stimulatory systems: Master tools to combat leishmaniasis

Disease management of leishmaniasis is appalling due to lack of a human vaccine and the toxicity and resistance concerns with limited therapeutic drugs. The challenges in development of a safe vaccine for generation and maintenance of robust antileishmanial protective immunity through a human administrable route of immunization can be addressed through immunomodulation and targeted delivery. The versatility of lipid based particulate system for deliberate delivery of diverse range of molecules including immunomodulators, antigens and drugs have essentially found pivotal role in design of proficient vaccination and therapeutic strategies against leishmaniasis. The prospects of lipid based preventive and curative formulations for leishmaniasis have been highlighted in this review.

Black bean (Phaseolus vulgaris L.) protein hydrolysates: Physicochemical and functional properties

Black bean protein hydrolysates obtained from pepsin and alcalase digestions until 120min of hydrolysis were evaluated by gel electrophoresis, relative fluorescence intensity, emulsifying properties, light micrograph of emulsions and in vitro antioxidant activity. The emulsion stability of the bean protein hydrolysates were evaluated during 30days of storage. The pepsin-treated bean protein hydrolysates presented higher degree of hydrolysis than the alcalase-treated protein hydrolysates. The alcalase-treated bean protein hydrolysates showed higher surface hydrophobicity. Moreover, the protein hydrolysates obtained with alcalase digestion presented higher emulsion stability during 30-days than those obtained from pepsin digestion. The protein concentrate and especially the hydrolysates obtained from alcalase digestion had good emulsion stability and antioxidant activity. Thus, they could be exploited as protein supplements in the diet as nutritional and bioactive foods.

Effect of cross-linker glutaraldehyde on gastric digestion of emulsified albumin

Human serum albumin (HSA) has been shown to be an ideal protein for nanoparticle preparation. These are usually prepared by using cross linker agents such as glutaraldehyde (GAD). Liquid lipid nanocapsules (LLN) constitute a new generation of nanoparticles more biocompatible and versatile for oral delivery of lipophylic drugs. The first barrier that an orally administered formulation must cross is the gastrointestinal tract. Hence, it is crucial to address the impact of gastrointestinal digestion on these structures in order to achieve an optimal formulation. This study evaluates the effect of gastric digestion on HSA emulsions structured with GAD as a model substrate for the preparation of LLN. This is done by SDS-PAGE, emulsion microstructure, and interfacial tension techniques. Our results demonstrate that the cross- linking procedure with GAD strongly inhibits pepsin digestion by formation of inter- and/or intramolecular covalent bonds between substrate amino acids. Emulsification of HSA also protects from gastric digestion probably by the orientation of the HSA molecule, which exposes the majority of pepsin cleaving sites preferably to the hydrophobic part of the oil-water interface. In this emulsified HSA, cross-linking with GAD at the interface promotes structural modifications on the HSA interfacial layer, restricting the access of pepsin to cleavage sites. We identify interfacial aspects underlying enzymatic hydrolysis of the protein. Assuring that HSA-GAD structures resist passage through the gastric compartment is crucial is important towards the rational design of oral delivery systems and the first step to get the complete digestion profile.

Effect of esterified oligosaccharides on the formation and stability of oil-in-water emulsions

Hydrophobically modified oligosaccharides were prepared by an enzyme-catalyzed reaction of maltodextrin/xylo-oligosaccharide and palmitic acid. Maltodextrin with dextrose equivalent (DE) of 16 palmitate (DE16_P) and 9 palmitate (DE9_P), as well as xylo-oligosaccharide palmitate (Xylo_P), were used. The effect of the concentration (10-50% (w/w)) and type of esterified oligosaccharides on the Sauter mean diameter and droplet-size distribution, the rate of coalescence (Kc), and the creaming properties of O/W emulsions were investigated. Esterified oligosaccharides (EO) adsorbed to the surface of the oil droplets. EO formed polydisperse O/W emulsions with particle sizes between 12 and 70 μm, depended on concentration of EO. The Sauter mean diameter, Kc, and the creaming index decreased markedly, with increasing concentration of EO. The type of ester minimally affected the Sauter mean diameter at each ester concentration. DE9_P inhibited coalescence and creaming more efficiently than other EO, mainly due to the higher viscosity of the continuous phase.

Effect of protein oxidation on kinetics of droplets stability probed by microrheology in O/W and W/O emulsions of whey protein concentrate

Whey protein concentrate (WPC) was oxidized by peroxyl radicals derived from 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) and the kinetics of droplet stability in O/W and W/O emulsions stabilized by oxidized WPC were evaluated by studying the micro-rheology. Degrees of protein oxidation were indicated by carbonyl concentration and emulsion types were distinguished by fluorescence microscopy. Oxidation resulted in free sulfhydryl groups degradation and surface hydrophobicity decrease. Moderate protein oxidation promoted to form diminutive droplets, which aggregated quickly to gel-network structure and decreased the motion rate of droplets, leading to the increased elasticity and viscosity, which led to better stability. Over-oxidation underwent severe droplet aggregation and sediment with increased motion rate, which resulted in instability of emulsions. The W/O emulsions of oxidized WPC were more inclined to block the motion of droplets and form a stable structure with higher viscosity, compared with the O/W emulsions.

Optimization of a combined electrocoagulation-electroflotation reactor

This work studies the efficiency of an electroflotation process for the separation of the solids produced during the electrocoagulation treatment of three different types of wastewater: kaolin suspension, coloured organic solution and oil-in-water emulsion. Additionally, a combined electrocoagulation-electroflotation reactor is designed and optimized taking into account the effect of current density, residence time, pollutant concentration and the ratio floated/settled solids. To do this, an experimental design with response surface methodology (RSM) has been used. Results show that electroflotation is a good alternative to the removal of oil microdrops and dyes, but it is not recommended for the separation of solids formed during electrocoagulation of colloid suspensions due to its high density. It has been found that the use of aluminium leads to better results than the use of iron in the treatment of oil-in-water emulsions and coloured solutions. In these cases, the use of a combined electrocoagulation-electroflotation reactor is recommended and the effect of the main inputs has been studied.

Enhancing oral bioavailability using preparations of apigenin-loaded W/O/W emulsions: In vitro and in vivo evaluations

We analyzed the physical properties and digestibility of apigenin-loaded emulsions as they passed through a simulated digestion model. As the emulsion passed through the simulated stages of digestion, the particle size and zeta potential of all the samples changed, except for the soybean oil-Tween 80 emulsion, in which zeta potential remained constant, through all stages, indicating that soybean oil-Tween 80 emulsions may have an effect on stability during all stages of digestion. Fluorescence microscopy was used to observe the morphology of the emulsions at each step. The in vivo pharmacokinetics revealed that apigenin-loaded soybean oil-Tween 80 emulsions had a higher oral bioavailability than did the orally administrated apigenin suspensions. These results suggest that W/O/W multiple emulsions formulated with soybean oil and tween 80 have great potential as targeted delivery systems for apigenin, and may enhance in vitro and in vivo bioavailability when they pass through the digestive tract.

Emulsion characteristics, chemical and textural properties of meat systems produced with double emulsions as beef fat replacers

In recent years, double emulsions are stated to have a promising potential in low-fat food production, however, there are very few studies on their possible applications in meat matrices. We aimed to investigate the quality of beef emulsion systems in which beef fat was totally replaced by double emulsions (W1/O/W2) prepared with olive oil and sodium caseinate (SC) by two-step emulsification procedure. Incorporation of W1/O/W2 emulsion resulted in reduced lipid, increased protein content, and modified fatty acid composition. W1/O/W2 emulsion treatments had lower jelly and fat separation, higher water-holding capacity and higher emulsion stability than control samples with beef fat. Increased concentrations of W1/O/W2 emulsions resulted in significant changes in texture parameters. TBA values were lower in W1/O/W2 emulsion treatments than control treatment after 60days of storage. In conclusion, our study confirms that double emulsions had promising impacts on modifying fatty acid composition and developing both technologically and oxidatively stable beef emulsion systems.

Assessment of partial coalescence in whippable oil-in-water food emulsions

Partial coalescence influences to a great extent the properties of final food products such as ice cream and whipped toppings. In return, the partial coalescence occurrence and development are conditioned, in such systems, by the emulsion's intrinsic properties (e.g. solid fat content, fat crystal shape and size), formulation (e.g. protein content, surfactants presence) and extrinsic factors (e.g. cooling rate, shearing). A set of methods is available for partial coalescence investigation and quantification. These methods are critically reviewed in this paper, balancing the weaknesses of the methods in terms of structure alteration (for turbidity, dye dilution, etc.) and assumptions made for mathematical models (for particle size determination) with their advantages (good repeatability, high sensitivity, etc.). With the methods proposed in literature, the partial coalescence investigations can be conducted quantitatively and/or qualitatively. Good correlation were observed between some of the quantitative methods such as dye dilution, calorimetry, fat particle size; while a poor correlation was found in the case of solvent extraction method with other quantitative methods. The most suitable way for partial coalescence quantification was implied to be the fat particle size method, which would give results with a high degree of confidence if used in combination with a microscopic technique for the confirmation of partial coalescence as the main destabilization mechanism.

Mesoporous silica nanoparticles with controllable morphology prepared from oil-in-water emulsions

Mesoporous silica nanoparticles are an important class of materials with a wide range of applications. This paper presents a simple protocol for synthesis of particles as small as 40nm and with a pore size that can be as large as 9nm. Reaction conditions including type of surfactant, type of catalyst and presence of organic polymer were investigated in order to optimize the synthesis. An important aim of the work was to understand the mechanism behind the formation of these unusual structures and an explanation based on silica condensation in the small aqueous microemulsion droplets that are present inside the drops of an oil-in-water emulsion is put forward.

Design and Characterization of Fibrin-Based Acoustically Responsive Scaffolds for Tissue Engineering Applications

Hydrogel scaffolds are used in tissue engineering as a delivery vehicle for regenerative growth factors. Spatiotemporal patterns of growth factor signaling are critical for tissue regeneration, yet most scaffolds afford limited control of growth factor release, especially after implantation. We previously found that acoustic droplet vaporization can control growth factor release from a fibrin scaffold doped with a perfluorocarbon emulsion. This study investigates properties of the acoustically responsive scaffold (ARS) critical for further translation. At 2.5 MHz, acoustic droplet vaporization and inertial cavitation thresholds ranged from 1.5 to 3.0 MPa and from 2.0 to 7.0 MPa peak rarefactional pressure, respectively, for ARSs of varying composition. Viability of C3H/10T1/2 cells, encapsulated in the ARS, did not decrease significantly for pressures below 4 MPa. ARSs with perfluorohexane emulsions displayed higher stability versus those with perfluoropentane emulsions, while surrogate payload release was minimal without ultrasound. These results enable the selection of ARS compositions and acoustic parameters needed for optimized spatiotemporally controlled release.

Encapsulation of Xenopus Egg and Embryo Extract Spindle Assembly Reactions in Synthetic Cell-Like Compartments with Tunable Size

Methods are described for preparing Xenopus laevis egg and embryo cytoplasm and encapsulating extract spindle assembly reactions in cell-like compartments to investigate the effects of cell size on intracellular assembly. Cytoplasm prepared from the eggs or embryos of individual frogs is screened for the ability to form interphase nuclei and metaphase spindles, and subsequently packaged, along with DNA, into droplets of varying size using microfluidics. The dimensions of these cell-like droplets are specified to match the range of cell diameters present in early embryo development. The scaling relationship between droplets and spindles is quantified using live fluorescence imaging on a spinning-disk confocal microscope. By comparing the encapsulated assembly of spindles formed from cytoplasmic extracts prepared from embryos at distinct stages of Xenopus early development, the influence of cell composition and cell size on spindle scaling can be evaluated. Because the extract system is biochemically tractable, the function of individual proteins in spindle scaling can be evaluated by supplementing or depleting factors in the cytoplasm.

Drug delivery and drug targeting with parenteral lipid nanoemulsions - A review

Lipid nanosized emulsions or nanoemulsions (NE) are oil in water dispersions with an oil droplet size of about 200nm. This size of oil droplets dispersed in a continuous water phase is a prerequisite for the parenteral, namely intravenous administration. Many parenteral nutrition and drug emulsions on the market confirm the safe use of NE over years. Parenteral emulsions loaded with APIs (active pharmaceutical ingredients) are considered as drug delivery systems (DDS). DDS focuses on the regulation of the in vivo dynamics, such as absorption, distribution, metabolism, and extended bioavailability, thereby improving the effectiveness and the safety of the drugs. Using an emulsion as a DDS, or through the use of surface diversification of the dispersed oil droplets of emulsions, a targeted increase of the API concentration in some parts of the human body can be achieved. This review focuses on NE similar to the marketed once with no or only low amount of additional surfactants beside the emulsifier from a manufacturing point of view (technique, used raw materials).

Dynamic and viscoelastic interfacial behavior of β-lactoglobulin microgels of varying sizes at fluid interfaces

HYPOTHESIS

Microgel particles formed from the whey protein β-lactoglobulin are able to stabilize emulsion and foam interfaces, yet their interfacial properties have not been fully characterized. Smaller microgels are expected to adsorb to and deform at the interface more rapidly, facilitating the development of highly elastic interfaces.

METHODS

Microgels were produced by thermal treatment under controlled pH conditions. Dynamic surface pressure and dilatational interfacial rheometry measurements were performed on heptane-water droplets to examine microgel interfacial adsorption and behavior. Langmuir compression and atomic force microscopy were used to examine the changes in microgel and monolayer characteristics during adsorption and equilibration.

FINDINGS

Microgel interfacial adsorption was influenced by bulk concentration and particle size, with smaller particles adsorbing faster. Microgel-stabilized interfaces were dominantly elastic, and elasticity increased more rapidly when smaller microgels were employed as stabilizers. Interfacial compression increased surface pressure but not elasticity, possibly due to mechanical disruption of inter-particle interactions. Monolayer images showed the presence of small aggregates, suggesting that microgel structure can be disrupted at low interfacial loadings. The ability of β-lactoglobulin microgels to form highly elastic interfacial layers may enable improvements in the colloidal stability of food, pharmaceutical and cosmetic products in addition to applications in controlled release and flavor delivery systems.

Formulation and stabilization of nano-/microdispersion systems using naturally occurring edible polyelectrolytes by electrostatic deposition and complexation

This review paper presents an overview of the formulation and functionalization of nano-/microdispersion systems composed of edible materials. We first summarized general aspects on the stability of colloidal systems and the roles of natural polyelectrolytes such as proteins and ionic polysaccharides for the formation and stabilization of colloidal systems. Then we introduced our research topics on (1) stabilization of emulsions by the electrostatic deposition using natural polyelectrolytes and (2) formulation of stable nanodispersion systems by complexation of natural polyelectrolytes. In both cases, the preparation procedures were relatively simple, without high energy input or harmful chemical addition. The properties of the nano-/microdispersion systems, such as particle size, surface charge and dispersion stability were significantly affected by the concerned materials and preparation conditions, including the type and concentration of used natural polyelectrolytes. These dispersion systems would be useful for developing novel foods having high functionality and good stability.

Interfacial adsorption and surfactant release characteristics of magnetically functionalized halloysite nanotubes for responsive emulsions

Magnetically responsive oil-in-water emulsions are effectively stabilized by a halloysite nanotube supported superparamagnetic iron oxide nanoparticle system. The attachment of the magnetically functionalized halloysite nanotubes at the oil-water interface imparts magnetic responsiveness to the emulsion and provides a steric barrier to droplet coalescence leading to emulsions that are stabilized for extended periods. Interfacial structure characterization by cryogenic scanning electron microscopy reveals that the nanotubes attach at the oil-water interface in a side on-orientation. The tubular structure of the nanotubes is exploited for the encapsulation and release of surfactant species that are typical of oil spill dispersants such as dioctyl sulfosuccinate sodium salt and polyoxyethylene (20) sorbitan monooleate. The magnetically responsive halloysite nanotubes anchor to the oil-water interface stabilizing the interface and releasing the surfactants resulting in reduction in the oil-water interfacial tension. The synergistic adsorption of the nanotubes and the released surfactants at the oil-water interface results in oil emulsification into very small droplets (less than 20μm). The synergy of the unique nanotubular morphology and interfacial activity of halloysite with the magnetic properties of iron oxide nanoparticles has potential applications in oil spill dispersion, magnetic mobilization and detection using magnetic fields.

A lipid based multi-compartmental system: Liposomes-in-double emulsion for oral vaccine delivery

The gastric mucosa provides the entry point for the majority of pathogens, as well as being the induction site for protective immunity; however, there remain few examples of oral vaccines due to the challenges presented by the gastrointestinal route. In this study, we develop a lipid-based multi-compartmental system for oral vaccine delivery. Specifically, we have optimised the formulation of a water-in-oil-in-water double emulsion prepared from a triglyceride - soya bean oil, using surfactants Span 80/Tween 80 and Pluronic F127 to stabilise the internal and external water phases, respectively. Into the internal water phase, we also incorporated a PEGylated liposome, prepared using hydrogenated phosphatidyl choline as a carrier for our model protein, FITC-labelled ovalbumin. We demonstrated the successful incorporation of intact liposomes into the internal water phase of the double emulsion using imaging techniques including cryo-SEM and confocal microscopy. Finally, we use in vitro release studies of FITC-ovalbumin, to provide further confirmation of the multi-compartmental structure of the double emulsion system and demonstrate significant extended release of the entrapped model antigen compared with PEG-liposomes; these characteristics are attractive for oral vaccine delivery.

Effect of emulsification and spray-drying microencapsulation on the antilisterial activity of transcinnamaldehyde

Spray-dried redispersible transcinnamaldehyde (TC)-in-water emulsions were prepared in order to preserve its antibacterial activity; 5% (w/w) TC emulsions were first obtained with a rotor-stator homogeniser in the presence of either soybean lecithin or sodium caseinate as emulsifiers. These emulsions were mixed with a 30% (w/w) maltodextrin solution before feeding a spray-dryer. The antibacterial activity of TC alone, TC emulsions with and without maltodextrin before and after spray-drying were assayed by monitoring the growth at 30 °C of Listeria innocua in their presence and in their absence (control). Whatever the emulsifier used, antilisterial activity of TC was increased following its emulsification. However, reconstituted spray-dried emulsions stabilised by sodium caseinate had a higher antibacterial activity suggesting that they better resisted to spray-drying. This was consistent with observation that microencapsulation efficiencies were 27.6% and 78.7% for emulsions stabilised by lecithin and sodium caseinate, respectively.

Drug encapsulated polymeric microspheres for intracranial tumor therapy: A review of the literature

Despite intensive surgical excision, radiation therapy, and chemotherapy, the current life expectancy for patients diagnosed with glioblastoma multiforme is only 12 to 15months. One of the approaches being explored to increase chemotherapeutic efficacy is to locally deliver chemotherapeutics encapsulated within degradable, polymeric microspheres. This review describes the techniques used to formulate drug encapsulated microspheres targeted for intracranial tumor therapy and how microsphere characteristics such as drug loading and encapsulation efficiency can be tuned based on formulation parameters. Further, the results of in vitro studies are discussed, detailing the varied drug release profiles obtained and validation of drug efficacy. Finally, in vivo results are summarized, highlighting the study design and the effectiveness of the drug encapsulated microspheres applied intracranially.

Formulation of mayonnaise with the addition of a bioemulsifier isolated from Candida utilis

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A biosurfactant from Candida utilis was employed in formulations of mayonnaises.

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The biosurfactant was tested on rats and in different formulations of mayonnaise.

⿢

The biosurfactant showed absence of toxic effect in the animals.

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The most stable formulation was obtained with guar gum and the biosurfactant.

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The innocuousness of the biosurfactant indicates its safe use in food emulsions.

Biosurfactants have a number of industrial applications due their diverse properties, such as emulsification, foaming, wetting, and surface activity. The aim of the present study was to produce a biosurfactant from Candida utilis and employ it in the formulation of a mayonnaise. The biosurfactant was produced in a mineral medium supplemented with glucose and canola waste frying oil at 150 rpm for 88 h. The product was biologically tested on rats and in different formulations of mayonnaise, which were submitted to microbiological evaluations. The biosurfactant was added to the diet of the rats for 21 days. Greater consumption was found of the experimental diet. Moreover, no changes were found in the liver or kidneys of the animals, demonstrating the absence of a toxic effect from the biosurfactant. Six different formulations of mayonnaise were prepared and tested regarding stability with the addition of carboxymethyl cellulose and guar gum (combined and isolated) after 30 days of refrigeration. The most stable formulation with the best quality was obtained with combination of guar gum and the isolated biosurfactant, with an absence of pathogenic microorganisms. In conclusion, the potential and innocuousness of the biosurfactant isolated from C. utilis indicates its safe use in food emulsions.

Structure-antioxidant activity relationships of o-hydroxyl, o-methoxy, and alkyl ester derivatives of p-hydroxybenzoic acid

Anti-DPPH radical effect as well as anti-peroxide activity of o-hydroxyl, o-methoxy, and alkyl ester derivatives of p-hydroxybenzoic acid in a bulk fish oil system and its O/W emulsion were investigated. Electronic phenomena, intra- and/or intermolecular hydrogen bonds, interfacial properties, and chemical reaction of the solvent molecules with phenolic compounds were considered to be mainly involved in the antiradical activities observed. Antioxidant activity of the phenolic acids derivatives as a function of these factors was variously affected by the environmental conditions which may occur in practice.

Characterization of flaxseed oil emulsions

The emulsifying capacity of surfactants (polysorbate 20, polysorbate 80 and soy lecithin) and proteins (soy protein isolate and whey protein isolate) in flaxseed oil was measured based on 1 % (w/w) of emulsifier. Surfactants showed significantly higher emulsifying capacity compared to the proteins (soy protein isolate and whey protein isolate) in flaxseed oil. The emulsion stability of the flaxseed oil emulsions with whey protein isolate (10 % w/w) prepared using a mixer was ranked in the following order: 1,000 rpm (58 min) ≈ 1,000 rpm (29 min) ≈ 2,000 rpm (35 min) >2,000 rpm (17.5 min). The emulsion stability of the flaxseed oil emulsions with whey protein isolate (10 % w/w) prepared using a homogenizer (Ultra Turrax) was independent of the speed and mixing time. The mean particle size of the flaxseed oil emulsions prepared using the two mixing devices ranged from 23.99 ± 1.34 μm to 47.22 ± 1.99 μm where else the particle size distribution and microstructure of the flaxseed oil emulsions demonstrated using microscopic imaging were quite similar. The flaxseed oil emulsions had a similar apparent viscosity and exhibited shear thinning (pseudoplastic) behavior. The flaxseed oil emulsions had L* value above 70 and was in the red-yellow color region (positive a* and b* values).

Development of stable flaxseed oil emulsions as a potential delivery system of ω-3 fatty acids

The objective of the present study was to develop a stable flaxseed oil emulsion for the delivery of omega-3 (ω-3) fatty acids through food fortification. Oil-in-water emulsions containing 12.5 % flaxseed oil, 10 % lactose and whey protein concentrate (WPC)-80 ranging from 5 to 12.5 % were prepared at 1,500, 3,000 and 4,500 psi homogenization pressure. Flaxseed oil emulsions were studied for its physical stability, oxidative stability (peroxide value), particle size distribution, zeta (ζ)-potential and rheological properties. Emulsions homogenized at 1,500 and 4,500 psi pressure showed oil separation and curdling of WPC, respectively, during preparation or storage. All the combinations of emulsions (homogenized at 3,000 psi) were physically stable for 28 days at 4-7 ºC temperature and did not show separation of phases. Emulsion with 7.5 % WPC showed the narrowest particle size distribution (190 to 615 nm) and maximum zeta (ζ)-potential (-33.5 mV). There was a slight increase in peroxide value (~20.98 %) of all the emulsions (except 5 % WPC emulsion), as compared to that of free flaxseed oil (~44.26 %) after 4 weeks of storage. Emulsions showed flow behavior index (n) in the range of 0.206 to 0.591, indicating higher shear thinning behavior, which is a characteristic of food emulsions. Results indicated that the most stable emulsion of flaxseed oil (12.5 %) can be formulated with 7.5 % WPC-80 and 10 % lactose (filler), homogenized at 3,000 psi pressure. The formulated emulsion can be used as potential omega-3 (ω-3) fatty acids delivery system in developing functional foods such as pastry, ice-creams, curd, milk, yogurt, cakes, etc.

Effect of the degree of substitution of octenyl succinic anhydride-banana starch on emulsion stability

Banana starch was esterified with octenylsuccinic anhydride (OSA) at different degree substitution (DS) and used to stabilize emulsions. Morphology, emulsion stability, emulsification index, rheological properties and particle size distribution of the emulsions were tested. Emulsions dyed with Solvent Red 26 showed affinity for the oil phase. Backscattering light showed three regions in the emulsion where the emulsified region was present. Starch concentration had higher effect in the emulsification index (EI) than the DS used in the study because similar values were found with OSA-banana and native starches. However, OSA-banana presented greater stability of the emulsified region. Rheological tests in emulsions with OSA-banana showed G'>G" values and low dependence of G' with the frequency, indicating a dominant elastic response to shear. When emulsions were prepared under high-pressure conditions, the emulsions with OSA-banana starch with different DS showed a bimodal distribution of particle size. The emulsion with OSA-banana starch and the low DS showed similar mean droplet diameter than its native counterpart. In contrast, the highest DS led to the highest mean droplet diameter. It is concluded that OSA-banana starch with DS can be used to stabilize specific emulsion types.

Formation and functionality of self-assembled whey protein microgels

Whey proteins spontaneously form spherical particles when heated in aqueous solutions at conditions where their net charge density is below a critical value. The particles are microgels consisting of a hydrated crosslinked network of proteins with a diameter between 100nm and 1μm. Stable suspensions of these microgels can be formed in a narrow range of conditions when the protein charge density is low enough to induce their formation, but high enough to inhibit further association into larger clusters or macroscopic gels. The formation of microgels and their application to stabilize emulsions and foams; form core-shell particles; form gels; or modify the texture of polysaccharide solutions and gels are reviewed.

Role of interfacial protein membrane in oxidative stability of vegetable oil substitution emulsions applicable to nutritionally modified sausage

The potential health risk associated with excessive dietary intake of fat and cholesterol has led to a renewed interest in replacing animal fat with nutritionally-balanced unsaturated oil in processed meats. However, as oils are more fluid and unsaturated than fats, one must overcome the challenge of maintaining both physical and chemical (oxidative) stabilities of prepared emulsions. Apart from physical entrapments, an emulsion droplet to be incorporated into a meat protein gel matrix (batter) should be equipped with an interactive protein membrane rather than a small surfactant, and the classical DLVO stabilization theory becomes less applicable. This review paper describes the steric effects along with chemical roles (radical scavenging and metal ion chelation) of proteins and their structurally modified derivatives as potential interface-building materials for oxidatively stable meat emulsions.

Improved oxidative barrier properties of emulsions stabilized by silica-polymer microparticles for enhanced stability of encapsulants

The materials encapsulated within oil-in-water emulsions are prone to oxidation due to the permeation of oxidative species across the oil-water interface and into the lipid phase. Thus, the oxidative barrier properties of the interfacial layer are pivotal in reducing oxidation within emulsified oils. To enhance these barrier properties, we explored an approach of stabilizing emulsions using 'silica-polymer microparticles'. We hypothesize that these microparticles will enhance the barrier properties of emulsion interfaces by mechanisms such as higher interfacial thickness and quenching of oxidative species before they permeate into the emulsions. Silica-ε-polylysine (Si-EPL) microparticles were synthesized by electrostatic aggregation of anionic silica nanoparticles and cationic ε-polylysine in the aqueous phase. Formation of Si-EPL microparticles was validated using particle size, ζ-potential and scanning electron microscopy measurements. These microparticles were subsequently used for emulsion stabilization. Emulsions stabilized by silica nanoparticles alone were used as control. Oxidative barrier properties were determined by measuring the rate of permeation of peroxyl radicals from the aqueous to the oil phase of the emulsion using fluorescence based methods. The rate of permeation of peroxyl radicals was significantly lower in emulsions stabilized by Si-EPL microparticles compared to that stabilized by silica nanoparticles. One of the mechanisms responsible for the observed effect was enhanced quenching of peroxyl radical by Si-EPL microparticles before they can permeate inside the oil phase. To further validate the results, stability of a model bioactive compound, retinol, encapsulated in these emulsions was compared. Consistent with peroxyl radical permeation measurements, emulsion stabilized by Si-EPL microparticles significantly improved the oxidative stability of retinol compared to that stabilized by silica nanoparticles alone. Thus, by engineering the physical properties of the interfacial layers, the oxidation of the encapsulants in emulsions can be controlled.

Microemulsion versus emulsion as effective carrier of hydroxytyrosol

Two edible Water-in-Oil (W/O) dispersions, an emulsion that remains kinetically stable and a microemulsion which is spontaneously formed, transparent and thermodynamically stable, were developed for potential use as functional foods, due to their ability to be considered as matrices to encapsulate biologically active hydrophilic molecules. Both systems contained Medium Chain Triglycerides (MCT) as the continuous phase and were used as carriers of Hydroxytyrosol (HT), a hydrophilic antioxidant of olive oil. A low energy input fabrication process of the emulsion was implemented. The obtained emulsion contained 1.3% (w/w) of surfactants and 5% (w/w) aqueous phase. The spontaneously formed microemulsion contained 4.9% (w/w) of surfactants and 2% (w/w) aqueous phase. A comparative study in terms of structural characterization of the systems in the absence and presence of HT was carried out. Particle size distribution obtained by Dynamic Light Scattering (DLS) technique and interfacial properties of the surfactants' layer, examined by Electron Paramagnetic Resonance (EPR) spectroscopy indicated the involvement of HT in the surfactant membrane. Finally, the proposed systems were studied for the scavenging activity of the encapsulated antioxidant toward galvinoxyl stable free radical showing a high scavenging activity of HT in both systems.