Temporal Control Over Complex, Simple, and Multiphase Coacervates Using Ureolysis and Ammonium Carbonate Decomposition

Complex coacervation between gelatin type B (GE) and chia mucilage (ChM) was studied. GE-ChM were mixed at mass ratios of 1:1, 2:1, 3:1, 4:1, and 1:2 in a pH range of 1.50 to 5.00, maintaining a total solid concentration of 0.2% (w/w), using turbidity and viscosity tests to obtain the highest yield of complex coacervates. To characterize the complex coacervates, morphology and Fourier-transform infrared spectroscopy (FTIR) were determined. The optimum yield for complex coacervation was achieved with a GE-ChM mass ratio of 2:1 and pH value of 3.6. The critical pH values associated with the formation of soluble (pHc ) and insoluble (pHɸ1 ) complexes, and complete dissociation (pHɸ2 ) at the optimum GE-ChM ratio were found to be 4.50, 4.10, and 2.00, respectively. It was observed that increasing the mass ratio of GE or ChM, the yield of complex coacervates decreased; the higher yields were obtained with the proportions of 2:1 and 1:1 with values of 68.25 ± 0.05% and 61.04 ± 0.05%, respectively. Capsules formed at mass ratios of 1:1, 2:1, and 3:1, had the characteristic grape agglomerate shape for complex coacervates. Further characterization with scanning electron microscopy (SEM) showed a spherical shape for capsules. FTIR spectrum of complex coacervates at optimum conditions had a combination of bands corresponding to GE and ChM, suggesting an interaction between GE-ChM during the formation of complex coacervates. Therefore, complex coacervates between GE-ChM can be formed, and could be used as an alternative as encapsulating agents to be applied in the food industry. PRACTICAL APPLICATION: Complex coacervation is a technique that is being studied in several applications in the food industry. However, studies are still being made to explore different possibilities of natural sources to be used in complex coacervation. This study showed that the combination of gelatin and chia mucilage may be an alternative as encapsulating agents for complex coacervation to be applied in the food industry.

Complex coacervation refers to the liquid-liquid phase separation (LLPS) process occurring between charged macromolecules. The study of complex coacervation is of great interest due to its implications in the formation of membraneless organelles (MLOs) in living cells. However, the impacts of the crowded intracellular environment on the behavior and interactions of biomolecules involved in MLO formation are not fully understood. To address this knowledge gap, we investigated the effects of crowding on a model protein-polymer complex coacervate system. Specifically, we examined the influence of sucrose as a molecular crowder and polyethylene glycol (PEG) as a macromolecular crowder. Our results reveal that the presence of crowders led to the formation of larger coacervate droplets that remained stable over a 25-day period. While sucrose had a minimal effect on the physical properties of the coacervates, PEG led to the formation of coacervates with distinct characteristics, including higher density, increased protein and polymer content, and a more compact internal structure. These differences in coacervate properties can be attributed to the effects of crowders on individual macromolecules, such as the conformation of model polymers, and nonspecific interactions among model protein molecules. Moreover, our results show that sucrose and PEG have different partition behaviors: sucrose was present in both the coacervate and dilute phases, while PEG was observed to be excluded from the coacervate phase. Collectively, our findings provide insights into the understanding of crowding effects on complex coacervation, shedding light on the formation and properties of coacervates in the context of MLOs.

Complex coacervation between β-lactoglobulin and Acacia gum: A nucleation and growth mechanism

Nanoencapsulation of zeaxanthin extracted from Lycium barbarum L. by complex coacervation with gelatin and CMC

Complex coacervates obtained from peptide leucine and gum arabic: Formation and characterization

Microspheres (MS) of Ketorolac Tromethamine (KT) for oral delivery were prepared by complex coacervation (method-1) and simple coacervation (method-2) methods without the use of chemical cross–linking agent (glutaraldehyde) to avoid the toxic reactions and other undesirable effects of the chemical cross-linking agents. Alternatively, ionotropic gelation was employed by using sodium-tripolyphosphate (Na-TPP) as cross linking agent. Chitosan and gelatin B were used as polymer and copolymer respectively. All the prepared microspheres were subjected to various physico-chemical studies, such as drug-polymer compatibility by Thin Layer Chromatography (TLC) and Fourier Transform Infra Red Spectroscopy (FTIR), surface morphology by Scanning Electron Microscopy (SEM), frequency distribution, encapsulation efficiency, in-vitro drug release characteristics and release kinetics. The physical state of drug in the microspheres was determined by Differential Scanning Calorimetry (DSC) and X-ray powder Diffractometry (XRD). TLC and FTIR studies indicated no drug-polymer incompatibility. All the MS showed release of drug by a fickian diffusion mechanism. DSC and XRD analysis indicated that the KT trapped in the microspheres existed in an amorphous or disordered-crystalline status in the polymer matrix. It is possible to design a controlled drug delivery system for the prolonged release of KT, improving therapy by possible reduction of time intervals between administrations.

In this research, gum Arabic (GA) and whey protein nanofibrils (WPN) were employed for the encapsulation of curcumin as a bioactive compound with low water solubility through the complex coacervation method. The optimum conditions for the formation of complex coacervates were found at WPN/GA weight ratio of 1:1 and pH value of 3.0. The resulting complexes showed a high ability for loading of curcumin as a bioactive cargo. Fluorescence spectroscopy showed that the curcumin was loaded in the hydrophobic core of WPN/GA coacervates. The characteristics of curcumin-loaded coacervates were also evaluated by XRD and FT-IR analysis. The curcumin-loaded complex coacervates dispersions showed a shear thinning behavior. They also showed a good surface activity which makes them excellent candidates to fabricate new functional food emulsions and beverages. The results indicated that the antioxidant activity and photo-stability of curcumin were significantly improved by encapsulation into WPN/GA complexes. A sustained-release profile also was investigated for curcumin from WPN/GA complexes in the simulated gastrointestinal conditions. This study suggested that the WPN/GA electrostatic-driven complexes can be used as efficient carriers for curcumin delivery.

Ethylcellulose microparticles containing chitosan and gelatin: pH-dependent release caused by complex coacervation

Complex Coacervate Formation on a Heterogeneous Membrane

Enhanced nutraceutical potential of cannabidiol derived from industrial hemp using plant based complex coacervates

The present work aimed to study the influence of the pH and protein ratio on the formation of complex coacervates of carboxymethylcellulose (CMC) and whey protein isolated nanoparticles (WPIN). These biopolymers and transglutaminase, as a cross-linking agent, were used to encapsulate sacha inchi oil (SIO) containing β-carotene (β-C). The stability of β-C from SIO microcapsules (β-SIO microcapsules) was evaluated under in vitro digestion using an INFOGEST 2.0 in vitro digestion protocol. The release of β-C in a simulated food model was studied, and mathematical models were used to determine the mechanism. A ratio of 1:6 (CMC/WPIN) at pH 3.5 was used for the formation of the complex. Chemical and morphological analyses suggested that SIO was microencapsulated and that a high encapsulation efficiency was obtained. The β-C from β-SIO microcapsules was preserved in vegetable oil (food model), and Fickian diffusion occurred. The β-C from β-SIO microcapsules was preserved under oral and gastric conditions, and higher release occurred during intestinal digestion when samples were subjected to in vitro digestion simulation. After in vitro digestion, the β-C from β-SIO microcapsules presented higher stability (83.37%) and acceptable bioaccessibility (31.16%). There are few studies in the literature of encapsulated SIO using the CMC/WPIN complex or studies of the release of β-carotene from SIO during in vitro digestion and in food simulants. The knowledge obtained in this study will facilitate the use and applications of β-C-loaded microcapsule delivery systems.

In this paper, for the first time, we have reported the formation of complex coacervate during interaction between hydrophobic protein, zein, and hydrophilic nanoclay, Laponite, in a 60% v/v ethanol solution at pH 4. Dynamic light scattering and viscosity measurements revealed the formation of zein–Laponite complexes during the interaction between zein at fixed concentration, CZ = 1 mg/mL, and varying concentrations of Laponite, CL (7.8 × 10–4 – 0.25% w/v). Further investigation of the zein–Laponite complexes using turbidity and zeta potential data showed that these complexes could be demarcated in three different regions: Region I, below the charge neutralization region (CZ = 1 mg/mL, CL ≤ 0.00625% w/v) where soluble complexes was formed during interaction between oppositely charged zein and Laponite; Region II, the charge neutralization region (CZ = 1 mg/mL, 0.00625 < CL ≤ 0.05% w/v) where zein–Laponite complexes form neutral coacervates; and Region III, the interesting overcharged coacervates region (CZ = 1 mg/mL, CL > 0.05% w/v). Investigation of coacervates using a fluorescence imaging technique showed that the size of neutral coacervates in region II was large (mean size = 1223.7 nm) owing to aggregation as compared to the small size of coacervates (mean size = 464.7 nm) in region III owing to repulsion between overcharged coacervates. Differential scanning calorimeter, DSC, revealed the presence of an ample amount of bound water in region III. The presence of bound water was evident from the presence of an additional peak at 107 °C in region III apart from normal enthalpy of evaporation of water from coacervates.

Pressure‐sensitive adhesives (PSA) were microencapsulated using simple and complex coacervation and aminoplaste. The microcapsules thus prepared were characterized by FTIR spectroscopy, particle size distribution, rheological behavior, and peeling tests. The microcapsules were isolated and found to be out of sticky indicating that the PSAs were indeed encapsulated. The prepared suspensions were deposited at the surface of a paper sheets and the dried labels were then pressed against each other. The ensuing complex was then characterized in terms of peeling forces and showed that the encapsulation using aminoplaste technique of a commercial PSA yielded peel energy of 170 J · m−2, which constitutes the recovering of about 68% of the adhesive power of the original nonencapsulated PSA.magnified image

The potential utilization of encapsulation techniques in food, pharmaceutical and agricultural products preparation, presents a new alternative for complementary technologies such as targeting delivery vehicles and carriers for active food ingredients. Encapsulation could be accomplished by different techniques like: simple or complex coacervation, emulsification technique, phase separation, spray drying, spray chilling or spray cooling, extrusion coating, freeze drying, fluidized-bed coating, liposomal entrapment, centrifugal suspension separation, co-crystallization and molecular inclusion complexation. Encapsulation is a method by which one bioactive material or mixture of materials is coated by the other material. It is designed for protection, isolation, assists in the storage and controlled release. A timely and targeted release improves the effectiveness of ingredients, broadens the application and ensures optimal dosage, thereby improving cost-effectiveness process for manufacturers. This review highlights recent innovations in encapsulation and controlled release technologies. In addition, design principle of novel peppermint oil delivery systems which displays the new structured biomaterials for capsules fabrication by complex coacervation technique, besides microemulsification method for bioactive material, Lactobacillus encapsulation and targeted release studies reported.

The main objective of this work is devoted to the microencapsulation process by the complex coacervation using two types of natural polymer namely sodium alginate and gelatin to encapsulate a pharmaceutical active ingredient of the “Diclofenac” family of analgesics and to prolong its release in vivo. In a first step, the influence of physicochemical parameters on the existing interactions between both polymers has been studied. The effects of pH, Pr : Ps (Protein: polysaccharide) ratio and the addition of salt concentration through the particle size and Zetametry by the dynamic light scattering technique, make it possible to experimentally limit the optimal domain of coacervate formation; which is used to formulate the Diclofenac-based microparticles. The results revealed a great influence of pH on the formation of the P r:Ps complex with an impact on the mean diameter (D42). The latter recorded a clear increase, with a decrease in the electro-kinetic potential reflecting the neutralization of the charges at pH 3.5-4. The results also showed a better coacervation (interaction between the polymers) for ratios of alginate / gelatin equal to 4/1 and 3/1. The formulation of microparticles based on Diclofenac by coacervation was subsequently characterized on the technical (size and texture) and biopharmaceutical levels, which revealed a prolonged type release of 8 h.