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The intestinal microflora has living microorganisms that promote the well-being and health of the intestine and indirectly of different systems of the body. When probiotic microorganisms are supplied in the correct dose and in an adequate manner, they contribute to the reduction of acquiring certain diseases; Probiotics have numerous properties that affect the microflora of the body, resulting in benefits mainly for intestinal health and the immune system, which can be supplied by nutraceutical products or functional foods. However, there are limitations in their use because they are sensitive under adverse environmental conditions, they degrade in food matrices under acidic conditions of the gastrointestinal tract, where they must exert their mechanism of action to generate beneficial effects on the health of the host. Therefore, it is important to implement strategies that provide protection to probiotics against unfavorable conditions, to significantly maintain viability during processing and in the digestive system. There are various encapsulation techniques, including ionic gelation and complex coacervation, both methods with great benefits for the protection of probiotic microorganisms and broad advantages for application in different food matrices; These techniques are made with non-toxic, natural materials approved for human consumption. This review aims to present important aspects of probiotic microorganisms in the food industry and the need for protective barriers, focusing mainly on encapsulation techniques by ionic gelation and complex coacervation., La microflora intestinal cuenta con microorganismos vivos que promueven el bienestar y la salud del intestino y de manera indirecta de diferentes sistemas del cuerpo. Cuando se suministran microorganismos probióticos en dosis correctas y de manera adecuada, estos contribuyen a la disminución de adquirir ciertas enfermedades; los probióticos cuentan con numerosas propiedades que inciden sobre la microflora del organismo resultando beneficiosos principalmente en la salud intestinal y en el sistema inmunológico, que pueden ser suministrados por productos nutraceúticos o por alimentos funcionales. Sin embargo, existen limitaciones en su uso debido a que son sensibles bajo condiciones adversas del entorno, se degradan en matrices alimentarias en condiciones ácidas del tracto gastrointestinal, lugar donde deben ejercer su mecanismo de acción para generar los efectos benéficos en la salud del hospedero. Por lo tanto, es importante la implementación de estrategias que brinden protección a los probióticos frente a condiciones no favorables, para mantener significativamente la viabilidad durante el procesamiento y en el sistema digestivo. Existen diversas técnicas de encapsulación, entre ellas la gelificación iónica y la coacervación compleja, ambos métodos con grandes bondades para la protección de microorganismos probióticos y amplias ventajas para la aplicación en diferentes matrices alimentarias; estas técnicas, se realizan con materiales no tóxicos, naturales y aprobados para el consumo humano. La presente revisión tiene por objetivo presentar aspectos importantes sobre los microorganismos probióticos en la industria de alimentos, en la salud, y la necesidad de las barreras de protección con enfoque principalmente en el método de gelificación iónica y coacervación compleja como técnicas emergentes de encapsulación.

The molecular characteristics of the food-grade polysaccharide gum acacia may vary depending on source, which could in turn significantly affect its behaviour as thickener, emulsifier and as a wall material in microencapsulation. In this study, five acacia gums (GA) from different sources were screened with respect to molecular weight distribution, interfacial tension, microencapsulation of salmon oil by complex coacervation and resulting oxidative stability of the oil. Bovine serum albumin (BSA) was used in combination with GA (BSA:GA = 1:1 w:w) for the coacervation. Interfacial tension was investigated for all GA alone and in combination with BSA at pH 5.5, pH 4.2 and pH 7, corresponding to the pH of emulsification, coacervation and neutral/reference conditions, respectively. Three of the five GA tested (GA from Sigma and the food grade GA Encapcia and Instant Gum BA from Nexira) resulted in stable complex coacervate microcapsules, with mean coacervate yields of the resulting microcapsules ranging from 34% to 76% depending on GA source, and a ∼100% microencapsulation yield. The food grade GA Encapcia and Instant gum BA were found to provide significantly better protection against oxidation than the Sigma GA, both as a function of the microencapsulation process and after storage for 12 months. The differences in performance of the GA are discussed in terms of molecular weight, GA variety and impurities.

Complex coacervation is a phase separation of a mixture into two immiscible liquid phases mainly due to electrostatic interactions between two oppositely charged polymers. Microencapsulation by complex coacervation, though highly effective and achievable at the bench-scale, is challenging to scale-up because of the complexity and high-cost of the process. Thus, I developed a novel complex coacervation process (herein referred to as the ‘CoCo process’) that combines the coacervation, shell hardening and drying steps into one step by spray drying. During spray drying, the base vaporizes upon atomization, lowering the pH of the atomized droplets and inducing the two oppositely charged polymers to associate by complex coacervation. Rapid moisture removal force tightens associations between the polymers, leading to formation of water-insoluble microcapsules that are collected at the outlet of the spray dryer. The CoCo process overcomes the commercialization barrier and appears as a promising technique to encapsulate various cargo for a wide range of applications. This work investigated how to control the barrier properties of matrix microcapsules formed by the CoCo process to stabilize the bioactive components and control the release of the bioactive components for various applications. First, as a proof concept, the potential of the CoCo process to encapsulate volatile oil was investigated by encapsulating D-limonene using gelatin and alginate as matrix building components, and succinic acid and a volatile base in the formulations to modulate the pH. Here I defined a metric termed as the extent of complex coacervation (ECC) to assess the extent to which all polymers within the particles participate in complex coacervation and it was defined as the fraction of polymers that do not solubilize from the CoCo particles when the spray dried powders are suspended in water. Insoluble CoCo particles were produced without chemical cross-linking, with extent of complex coacervatio

Complex coacervation is a phase separation of a mixture into two immiscible liquid phases mainly due to electrostatic interactions between two oppositely charged polymers. Microencapsulation by complex coacervation, though highly effective and achievable at the bench-scale, is challenging to scale-up because of the complexity and high-cost of the process. Thus, I developed a novel complex coacervation process (herein referred to as the ‘CoCo process’) that combines the coacervation, shell hardening and drying steps into one step by spray drying. During spray drying, the base vaporizes upon atomization, lowering the pH of the atomized droplets and inducing the two oppositely charged polymers to associate by complex coacervation. Rapid moisture removal force tightens associations between the polymers, leading to formation of water-insoluble microcapsules that are collected at the outlet of the spray dryer. The CoCo process overcomes the commercialization barrier and appears as a promising technique to encapsulate various cargo for a wide range of applications. This work investigated how to control the barrier properties of matrix microcapsules formed by the CoCo process to stabilize the bioactive components and control the release of the bioactive components for various applications. First, as a proof concept, the potential of the CoCo process to encapsulate volatile oil was investigated by encapsulating D-limonene using gelatin and alginate as matrix building components, and succinic acid and a volatile base in the formulations to modulate the pH. Here I defined a metric termed as the extent of complex coacervation (ECC) to assess the extent to which all polymers within the particles participate in complex coacervation and it was defined as the fraction of polymers that do not solubilize from the CoCo particles when the spray dried powders are suspended in water. Insoluble CoCo particles were produced without chemical cross-linking, with extent of complex coacervatio

Essential Oils (EOs) are a substance composed of two phases. A liquid and volatile substance that has aromatic, antibacterial, antioxidant. The properties of EOs are not new to humanity. Indeed, these began to take a role from the first civilizations (Egyptian civilization). Where EOs used as preservatives and flavourings. Nowadays, the use of the EOs is the same. Avoid the growth of bacteria and viruses (theoretical) in food, the contact surface (chairs of the bus), tables, fabrics (clothes). During these last years, the industrial world took the relevance of the microencapsulation technique. This technique pretends to capture the EOs to reach two main objectives. First, contain all his active compounds into a microcapsule to prevent the degradation of the environment. Second, release control into the media, contact surface, or fabrics. Microencapsulation is a beneficial technology to improve fields of biomedicine and the food industry. Besides, the impregnation of these microcapsules on fabrics can develop a lot of new properties. Indeed, the antibacterial and antioxidant properties. The amount of these properties requires an accurate and meticulous methodology. The formation of the microcapsules is very complicated to explain from one point of view. Therefore, it is necessary to collect all the available data. Nevertheless, the research count with very sophisticated equipment, which can provide us with very accurate results. Nanosizer, Spectrophotometer, SEM. The meaning of this research is to make sure if it is possible to control either the diffusion of the EOs and his chemist properties (diameter and morphology). Simple coacervation of microcapsules of ß-cyclodextrin (B-CD) with lavender (L) is the technique that we will follow at the beginning of this research. These simple microcapsules will be impregnated in different fabrics: Polyester (PET), Cotton (COT), and Polyamide (PA). After his impregnation, we must wait until dry in the ambient and make the drug d, Peer Reviewed, Postprint (published version)

The cashew (Anacardium occidentale) is a tropical flowering tree that generates globally over 4 million metric tons of cashew nuts a year. Although the cashew nut is the most well-known product, other byproducts can produce additional value, including cashew apples, cashew nutshell liquid, cardanol, and cashew gum. Over the years, a fair amount of R&D has been done on cashew byproducts in order to increase their value for different applications. In order to stimulate further interest in the use of these products, a selective review of the applications and chemical modifications of these byproducts has been done in this Review. A particular emphasis has been made on the recent publications by authors on cashew gum and cardanol derivatives to show how the use of specific polymer reactions (e.g., ene reaction, aminohydrin formation, amine-formaldehyde reaction, and polysaccharide ether and ester formation) and physical processes (e.g., polymer blending, complex coacervation, microencapsulation, and electrospraying) can enhance the properties of these agro-based materials.

The study was conducted to understand the effect of zein-gum Arabic (GA) complex coacervates prepared by ultrasound treatment on the encapsulation of resveratrol. Compared with zein, zein-GA complex coacervation largely increased the encapsulation efficiency from 26.19% to 55.85% and it was further increased to 74.2% after sonication. Also, prominent rise in the related loading capacities from 2.79% to 6.01% was noted. The increased particle size by the addition of GA and polydispersity index of the ternary complex was dramatically reduced after ultrasound treatment; the absolute values of zeta potential were increased. The hydrogen bonds, electrostatic interactions and hydrophobic effects were the main driving forces for the formation of the ternary complex particles. Ultrasound treatment strengthened the hydrogen bonding and electrostatic interactions, resulting in the formation of compact and homogeneous composite nanoparticles with smaller particle size, which was further confirmed by scanning electron microscope and atomic force microscope. These findings reveal the mechanism of ultrasound enhancing the zein-GA complex coacervation to load resveratrol, and demonstrate its promising effect in modifying protein-polysaccharide complex coacervation as a delivery carrier in the functional food and beverage industry.

Plant-based ingredients are key building blocks for future sustainable advanced materials. Functionality is typically higher for highly purified plant-based ingredients, but this is at the expense of their sustainability value. Here, a method is introduced for creating a soft functional material, with structural elements ranging from the nanometer to the millimeter scale, directly from legume flours. Globulins from soy and pea flours are extracted in their native state at acidic pH and mixed with gum arabic, resulting in liquid-liquid phase separation into a dilute phase and a viscoelastic complex coacervate. Interfacial tensions of the coacervates, determined via AFM-based probing of capillary condensation, are found to be very low (γ= 48.5 and 32.3 μN/m for, respectively, soy and pea), thus promoting the deposition of a shell of coacervate material around oil droplets. Despite the complex nature of the starting material, the dependence of interfacial tensions on salt concentrations follows a scaling law previously shown to hold for model complex coacervates. Curing of the coacervate material into a strong and purely elastic hydrogel is shown to be possible via simple heating, both in bulk and as a shell around oil droplets, thus providing proof of principle for the fabrication of precise core-shell microcapsules directly from legume flours.

The present study evaluated the effect of the incorporation of copaiba oil, in direct and in microencapsulated form, into films based on Xanthosoma mafaffa Schott starch. Initially, the characterization of copaiba oil by gas chromatograph coupled with mass spectrometry (GC-MS) and its antimicrobial activity against gram-positive and gram-negative bacteria was performed. The films were produced by the casting technique and characterized in relation to physical, chemical, structural, and antimicrobial activity. Sesquiterpenes, mainly ß-caryophyllene, were the predominant compounds in copaiba oil, showing antimicrobial activity against B. subtilis and S. aureus. The films showed forming capacity, however, was observed a decrease in solubility and revealed an increase in hydrophobic characteristics. However, the oil reduced the tensile strength and elongation, while the microcapsules did not influence the mechanical properties in comparison to the control film. From microstructure analysis, changes in the films roughness and surface were observed after the addition of oil both directly and in microencapsulated form. Films incorporated with microparticles were able to inhibit the gram-positive bacteria tested, forming inhibition zones, indicating that the encapsulation of copaiba oil was more efficient for protecting bioactive compounds from the oil, suggesting the possible application of mangarito starch-based films incorporated with copaiba oil as biodegradable packaging, This work was supported by the Coordination for the Improvement of Higher Education Personnel (CAPES) 1808888, Postprint (published version)

Most commercially available soft tissue glues offer poor performance in the human body. We have developed an injectable adhesive whose setting mechanism is activated by a change in environmental factors, i.e., temperature and/or ionic strength. The material and setting process are inspired by the adhesive processing mechanism observed in natural maritime glues. Complex coacervation, a liquid–liquid phase separation between oppositely charged polyelectrolytes, is thought to play an important role in the processing. Complex coacervates are characterized by a high water content, which inevitably weakens the glue. Here, we aim to increase the adhesive performance by systematically tuning the water content. Among the several strategies here explored, the most effective one is the mechanical removal of water using an extruder, resulting in an increase of work of adhesion by 1 order of magnitude compared to the original formulation.

Many marine organisms have developed adhesives that are able to bond under water, overcoming the challenges associated with wet adhesion. A key element in the processing of several natural underwater glues is complex coacervation, a liquid–liquid phase separation driven by complexation of oppositely charged macromolecules. Inspired by these examples, the development of a fully synthetic complex coacervate-based adhesive is reported with an in situ setting mechanism, which can be triggered by a change in temperature and/or a change in ionic strength. The adhesive consists of a matrix of oppositely charged polyelectrolytes that are modified with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) grafts. The adhesive, which initially starts out as a fluid complex coacervate with limited adhesion at room temperature and high ionic strength, transitions into a viscoelastic solid upon an increase in temperature and/or a decrease in the salt concentration of the environment. Consequently, the thermoresponsive chains self-associate into hydrophobic domains and/or the polyelectrolyte matrix contracts, without inducing any macroscopic shrinking. The presence of PNIPAM favors energy dissipation by softening the material and by allowing crack blunting. The high work of adhesion, the gelation kinetics, and the easy tunability of the system make it a potential candidate for soft tissue adhesion in physiological environments.

Underwater adhesion represents a huge technological challenge as the presence of water compromises the performance of most commercially available adhesives. Inspired by natural organisms, we have designed an adhesive based on complex coacervation, a liquid-liquid phase separation phenomenon. A complex coacervate adhesive is formed by mixing oppositely charged polyelectrolytes bearing pendant thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) chains. The material fully sets underwater due to a change in the environmental conditions, namely temperature and ionic strength. In this work, we incorporate silica nanoparticles forming a hybrid complex coacervate and investigate the resulting mechanical properties. An enhancement of the mechanical properties is observed below the PNIPAM lower critical solution temperature (LCST): this is due to the formation of PNIPAM-silica junctions, which, after setting, contribute to a moderate increase in the moduli and in the adhesive properties only when applying an ionic strength gradient. By contrast, when raising the temperature above the LCST, the mechanical properties are dominated by the association of PNIPAM chains and the nanofiller incorporation leads to an increased heterogeneity with the formation of fracture planes at the interface between areas of different concentrations of nanoparticles, promoting earlier failure of the network-an unexpected and noteworthy consequence of this hybrid system.

The mechanism that leads to liquid-liquid phase separation (LLPS) of the tau protein, whose pathological aggregation is implicated in neurodegenerative disorders, is not well understood. Establishing a phase diagram that delineates the boundaries of phase co-existence is key to understanding whether LLPS is an equilibrium or intermediate state. We demonstrate that tau and RNA reversibly form complex coacervates. While the equilibrium phase diagram can be fit to an analytical theory, a more advanced model is investigated through field theoretic simulations (FTS) that provided direct insight into the thermodynamic driving forces of tau LLPS. Together, experiment and simulation reveal that tau-RNA LLPS is stable within a narrow equilibrium window near physiological conditions over experimentally tunable parameters including temperature, salt and tau concentrations, and is entropy-driven. Guided by our phase diagram, we show that tau can be driven toward LLPS under live cell coculturing conditions with rationally chosen experimental parameters.

Phase separation of multivalent protein and RNA molecules underlies the biogenesis of biomolecular condensates such as membraneless organelles. In vivo, these condensates encompass hundreds of distinct types of molecules that typically organize into multilayered structures supporting the differential partitioning of molecules into distinct regions with distinct material properties. The interplay between driven (active) versus spontaneous (passive) processes that are required for enabling the formation of condensates with coexisting layers of distinct material properties remains unclear. Here, we deploy systematic experiments and simulations based on coarse-grained models to show that the collective interactions among the simplest, biologically relevant proteins and archetypal RNA molecules are sufficient for driving the spontaneous emergence of multilayered condensates with distinct material properties. These studies yield a set of rules regarding homotypic and heterotypic interactions that are likely to be relevant for understanding the interplay between active and passive processes that control the formation of functional biomolecular condensates.

The mechanism that leads to liquid-liquid phase separation (LLPS) of the tau protein, whose pathological aggregation is implicated in neurodegenerative disorders, is not well understood. Establishing a phase diagram that delineates the boundaries of phase co-existence is key to understanding whether LLPS is an equilibrium or intermediate state. We demonstrate that tau and RNA reversibly form complex coacervates. While the equilibrium phase diagram can be fit to an analytical theory, a more advanced model is investigated through field theoretic simulations (FTS) that provided direct insight into the thermodynamic driving forces of tau LLPS. Together, experiment and simulation reveal that tau-RNA LLPS is stable within a narrow equilibrium window near physiological conditions over experimentally tunable parameters including temperature, salt and tau concentrations, and is entropy-driven. Guided by our phase diagram, we show that tau can be driven toward LLPS under live cell coculturing conditions with rationally chosen experimental parameters.

Phase separation of multivalent protein and RNA molecules underlies the biogenesis of biomolecular condensates such as membraneless organelles. In vivo, these condensates encompass hundreds of distinct types of molecules that typically organize into multilayered structures supporting the differential partitioning of molecules into distinct regions with distinct material properties. The interplay between driven (active) versus spontaneous (passive) processes that are required for enabling the formation of condensates with coexisting layers of distinct material properties remains unclear. Here, we deploy systematic experiments and simulations based on coarse-grained models to show that the collective interactions among the simplest, biologically relevant proteins and archetypal RNA molecules are sufficient for driving the spontaneous emergence of multilayered condensates with distinct material properties. These studies yield a set of rules regarding homotypic and heterotypic interactions that are likely to be relevant for understanding the interplay between active and passive processes that control the formation of functional biomolecular condensates.

Clove oil was emulsified in 1% w/w chitosan (CC emulsions) and 2.5% w/w sodium alginate matrix (CA emulsions) containing Tween 80 as the surfactant. Different homogenization speeds (5,000, 10,000, 15,000 and 20,000 rpm) were used to produce the emulsions, and the stability of the emulsions during storage (29 days) was determined. The stability of the emulsions containing clove oil prior to the solidification process was assessed when chitosan and sodium alginate were used as encapsulating materials. Different homogenization speeds resulted in polydisperse emulsions with a size of 2–3 μm and 90% of stability after 29 days of storage. Different homogenization speeds did not significantly affect the concentrations of the active compounds contained in the emulsions. However, these concentrations changed significantly after 29 days of storage when sodium alginate was used to make the emulsions and the homogenization speeds were ≥ 10,000 rpm. High temperature caused by the high viscosity of the solution and high energy dissipation during homogenization suggested that the emulsions composed of sodium alginate were unstable. Chitosan enabled a longer processing time during the clove oil encapsulation process compared to sodium alginate, when emulsification by homogenization was used. The stability of the emulsion of the clove oil-in-chitosan matrix prior to the solidification step was superior.

In recent years, people’s dietary habits become more oriented toward healthy, safe, and, at the same time, tasty food. The perception of food taste is mostly affected by the addition of flavors and aromas during processing. Due to sensitivity of flavors and aromas in their native form, aroma encapsulation is already well established in the food industry. The benefits ascribed to encapsulation are reflected in easier handling of liquid flavors by its conversion into a dry form, improved stability when exposed to oxygen, light, and/or elevated temperatures, improved shelf-life, decreased release of volatile flavor components, masking of off-flavors and off-tastes, ability to impact textural properties of final products, and prolonged/controlled release. Among numerous encapsulation methods, spray drying has been predominantly used for encapsulation of flavors and aromas. However, the innovations in the field of encapsulation, particularly galloping nanotechnologies, have gained considerable attention from the food sector in the past decade, with applications for aromas as well as for other food compounds. This chapter reviews the current state of knowledge on nanoencapsulation of aromas and flavors, overviewing the processes and techniques utilized for coacervation, nanoprecipitation, molecular inclusion, and production of nanoparticulate formulations such as nanoemulsions, liposomes, solid–lipid nanoparticles (SLNs), and nanostructure lipid carriers (NLCs). Furthermore, the chapter gives insight into physicochemical and morphological characteristics of aroma nanoencapsulates, summarizing advantages and limitations of aroma nanoscale formulations versus microparticle formulations produced by conventional microencapsulation technologies. Finally, a critical prospect of potential application of aroma nanoencapsulates in real food products will be given, supported by examples available in literature.

Microencapsulation of fish oil was investigated using gelatin/SDS/NaCMC as the coating materials. The microencapsulation efficiency (EE) of microencapsulated fish oil (MFO) was investigated with respect to three variables including the Concentration of Wall Material (CWM), Ratio of Core and Wall Material (RCW) and the pH. The response surface model for microencapsulation efficiency showed a high coefficient of determination and a non-signi?cant lack of ?t (p < 0.05). The optimum microencapsulation efficiencies were 75.2

Microencapsulation of fish oil was investigated using gelatin/SDS/NaCMC as the coating materials. The microencapsulation efficiency (EE) of microencapsulated fish oil (MFO) was investigated with respect to three variables including the Concentration of Wall Material (CWM), Ratio of Core and Wall Material (RCW) and the pH. The response surface model for microencapsulation efficiency showed a high coefficient of determination and a non-signi?cant lack of ?t (p < 0.05). The optimum microencapsulation efficiencies were 75.2

Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6 mM) and the binding stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of lysozyme determined by differential scanning calorimetry. Furthermore, the protein stability of lysozyme was found to be improved upon complexation during a 12-weeks storage study at room temperature, as shown by a significant increase in recovered protein when complexed (94 ± 2% and 102 ± 5% depending on the polymer-protein weight to weight ratio) compared to 89 ± 2% recovery for uncomplexed protein. This study shows the potential of hyaluronic acid to be used in combination with complex coacervation to increase the physical stability of pharmaceutical protein formulations.

Microencapsulation of fish oil was investigated using gelatin/SDS/NaCMC as the coating materials. The microencapsulation efficiency (EE) of microencapsulated fish oil (MFO) was investigated with respect to three variables including the Concentration of Wall Material (CWM), Ratio of Core and Wall Material (RCW) and the pH. The response surface model for microencapsulation efficiency showed a high coefficient of determination and a non-signi?cant lack of ?t (p < 0.05). The optimum microencapsulation efficiencies were 75.2

Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6 mM) and the binding stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of lysozyme determined by differential scanning calorimetry. Furthermore, the protein stability of lysozyme was found to be improved upon complexation during a 12-weeks storage study at room temperature, as shown by a significant increase in recovered protein when complexed (94 ± 2% and 102 ± 5% depending on the polymer-protein weight to weight ratio) compared to 89 ± 2% recovery for uncomplexed protein. This study shows the potential of hyaluronic acid to be used in combination with complex coacervation to increase the physical stability of pharmaceutical protein formulations.

This study describes the development of a biodegradable nanoparticulate system for the intranasal delivery of multiple proteins. Chitosan (CS)–dextran sulphate (DS) nanoparticles were developed and optimised for the incorporation of pertussis toxin (PTX) and a potential targeting ligand (immunoglobulin-A, IgA). In vitro characterization and in vivo uptake studies were performed for the evaluation of developed nanoparticles. The ratio of CS to DS, the order of mixing and pH of nanoparticle suspension were identified as important formulation factors governing the size and zeta potential of nanoparticles. An optimised CS–DS nanoparticle formulation prepared with the CS to DS weight ratio of 3 : 1 was used to load PTX and/or IgA. Entrapment efficiency of >90% was obtained for both. The in vivo uptake of IgA-loaded CS–DS nanoparticles in mice showed a preferential uptake of nanoparticles probably by nasal membranous or microfold cells following intranasal administration. The results of this study indicate the potential application of IgA-loaded CS–DS nanoparticles as a nasal vaccine delivery system.

The effect of material properties on complex coacervation of whey protein and gum Arabic from various sources was investigated. In this study, it was demonstrated that material properties of whey protein isolates and gum Arabic affect the complex coacervation process significantly. For whey protein, the coacervation capability could be correlated with their level of denaturation and calcium content. For gum Arabic, both material sources and salt content were found to be attributing factors to their coacervation capability. This study facilitated the development of Omega-3 lipids microcapsules with promising performances in certain food applications.