Coacervate Yield Research Articles

Fabrication of cryogel polyelectrolyte complex of Tragacanth gum and chitosan with potential biological applications

To provide more insight into the potential applications of the biocompatible polyelectrolyte complexes (PECs) of Tragacanth gum (TG) and chitosan (CS) in the biological fields, the PEC cryogel of TG and CS were fabricated. Different TG:CS ratios were examined to optimize the PEC characteristics. Based on coacervation yield, water absorption, supernatant viscosity, turbidity, and rheological properties, 18:2 was chosen as the optimized ratio of TG:CS. The pH = 4 was selected as the optimized point, resulting in the highest level of interactions between anionic and cationic polysaccharides. The zeta potential of PECs was indicative of the charge neutralization between polyanions and polycations which were also studied by FTIR spectra. The cryogel exhibited a macroporous plate structure in leaf-like form and narrowed mesopores distributed around 2.4 and 4.6 nm. PECs exhibited anti-bacterial activities, reducing 95 % of E. coli within 1 h and 99.9 % after 24 h, as well as 80 % of S. aureus after 1 h and 99.9 % after 24 h. TG:CS cryogel adhered to the human fibroblast cell lines (HFFF2) without cytotoxicity effects. The scratch assay validated that the cryogel effectively induced wound closure in human fibroblast cells within 48 h.

Influence of pH fractionation and salt on Bambara protein–gum arabic interaction and insoluble complex formation

Proteins exhibit remarkable interaction with polysaccharides to form complexes with novel functionality. Nevertheless, the formation of insoluble complexes close to the protein isoelectric point (pI) results in protein–protein interference, low coacervates yield, and limited application in acidified food systems. Hence, pH fractionation with salt was used to extract Bambara groundnut protein to induce a shift in optimum pH (pHopt) of insoluble complexes formed with gum arabic, ultimately improving protein and coacervates yields. Turbidimetric analyses were employed to monitor the interaction between Bambara groundnut protein and gum arabic. Protein isolates from optimised fractionation conditions and insoluble complexes were characterised. The most effective fractionation condition was achieved at pH 2.95, 0.28 M NaCl, producing a substantial pHopt shift to 3.4. This shift was associated with the formation of spherical microparticle complexes and an impressive 70% coacervate yield. Changes in patterns of protein–gum arabic interaction were associated with an increased content of β-sheet, enrichment of legumin subunits, and basic amino acids of the isolate. This approach successfully shifted the formation of insoluble complexes towards a high-acid pH environment, notably away from the pI. Findings from this study create a prospect for future utilisation of pulse grain protein-gum arabic complexes in acidic beverage development.

Microencapsulation of turmeric oleoresin: complex coacervation and crosslinking strategies for improving encapsulation efficiency and stability in gastrointestinal simulated fluids

Turmeric oleoresin microcapsules were prepared by complex coacervation of gum arabic (GA) and chitosan (Ch) using genipin as a crosslinker. For this propose, the effect of pH and the biopolymer mass ratio ( R GA / Ch pH ) on the zeta-potential and coacervate yield and their viscoelastic properties were evaluated. A liquid-like behavior was found for all the samples in the small- and large-amplitude oscillatory shear regions, with sample R 5 4.5 having the highest viscoelastic properties. Samples R 6 3 , R 5 4.5 and R 4 6 with the highest coacervate yield (∼98%) for each pH chosen to produce the microcapsules. Then, turmeric oleoresin-gum arabic emulsions were produced and characterized. The pH affected the droplet size and charge. At pH 3.0, the droplets were about 50 nm and had a negative charge. At pH 4.5 and 6.0, the droplets were larger but more negatively charged. These emulsions were coated with chitosan and crosslinked with genipin were lyophilized to make microcapsules, showing high encapsulation efficiency (>98%) and low surface oil content (4.5–9.0%). The crosslinked turmeric oleoresin microcapsules showed lower swelling and water uptake in gastrointestinal media than did the uncrosslinked powders. The results of this research will contribute to the knowledge of coacervate systems for nutraceutical applications.

Hazelnut Protein and Sodium Alginate Complex Coacervates: An Effective Tool for the Encapsulation of the Hydrophobic Polyphenol Quercetin.

For valorization purposes of hazelnut byproducts, complex coacervation of hazelnut protein isolate (HPI) with sodium alginate (NaAlg) was investigated by turbidimetric analysis and zeta potential determination as a function of pH and protein/alginate mixing ratio. HPI-NaAlg complex coacervates were used as an encapsulating material of quercetin (QE) at different concentrations. The optimal pH and mixing ratio resulting in the highest turbidity and neutral charge were 3.5 and 6:1, respectively. The coacervation yield was 74.9% in empty capsules and up to 90.0% in the presence of QE. Under optimal conditions, HPI-NaAlg complex coacervates achieved an encapsulation efficiency higher than 99% in all coacervate/QE formulations. Fourier transform infrared spectroscopy (FTIR) results revealed the occurrence of electrostatic interactions between different functional groups within the ternary complex in addition to hydrogen and hydrophobic interactions between QE and HPI. HPI-NaAlg complex coacervates can serve as an alternative matrix for the microencapsulation of bioactive ingredients with low water solubility in food formulations, which adds an additional valorization of hazelnut byproducts.

Pea protein isolate-kappa-carrageenan complex coacervate as a lecithin substitute and their effect on physical properties, polymorphism, and melting behaviour of dark chocolates

This study used pea protein isolate (4% w/w) and kappa-carrageenan (4% w/w) to prepare complex coacervate through electrostatic interactions by optimizing the pH and ratio of protein-to-polysaccharide. The maximum coacervate yield of 81% was achieved at the optimized pH of 3.0 and the protein-to-polysaccharide ratio of 4:1. The optimized coacervate at various concentrations (1, 1.5, 2, 2.5, and 3% w/v) was assessed to emulsify cocoa butter to water fractions. The 2% w/v of complex coacervate successfully emulsified up to 40% aqueous phase in cocoa butter to water fractions whereas complex coacervates at 1%, 1.5%, 2.5%, and 3% w/v were found to stabilize only 20% aqueous phase. The storage and temperature stability of emulsions were higher upon usage of 2% w/v complex coacervate as the serum layer separation was minimal. Based on the emulsion stability observations, complex coacervate (2% w/v) was used to partially and completely substitute lecithin in dark chocolates. The results showed that irrespective of the emulsifiers utilized, the polymorphism and melting behaviour of all chocolates remained the same and retained the desired polymorphic form V. The moisture content and particle size distribution of chocolates did not exceed the acceptable limit. The Casson plastic viscosity (ηca), Casson yield stress (τ0c), and hardness (N) of chocolates significantly (p < 0.05) increased upon increasing the complex coacervate. The present findings revealed that partial substitution (50%) of lecithin with complex coacervate is highly promising for the production of dark chocolates while retaining the desirable flow properties and polymorphism.

Efficacy of almond gum for coacervation with whey protein isolate- optimization, functionality and characterization: A comparison with high-methoxyl pectin

Complex coacervates of whey protein isolate (WPI) and two polysaccharides (almond gum (AG) and high methoxyl pectin (HMP)) under the different pHs (2.5–6.0) and biopolymer mass ratios (1:1–6:1) were prepared to achieve the maximum coacervate yield (CY). The optimum pH and mixing ratio to obtain the maximum CY of WPI-AG (75.93 %) and WPI-HMP (53.0 %) coacervates were 4.3 and 2:1, and 3.5 and 3:1, respectively. Although higher serum layers in emulsions stabilized by WPI-AG/HMP coacervates were detected at the 90 °C, remarkable heat stability under processing temperatures was obtained in ex-situ emulsions with both complex coacervates. Significantly more cold-storage and ionic stabilities were observed for emulsions formulated with WPI-AG than WPI-HMP. Peak shifts in FTIR spectra in the WPI-AG coacervate compared to the individual WPI and AG biopolymers revealed strong electrostatic interactions between these biopolymers. The absence of crystalline peaks for AG and HMP in X-ray diffraction (XRD) spectra confirmed the complexation of AG and HMP with WPI. Thermogravimetric and microstructural analyses showed that porous, loose mesh-like WPI-AG coacervates had superior thermal stability and structural integrity compared to WPI-HMP coacervates and individual biopolymers, which evidenced a more gradual weight loss pattern. WPI-AG coacervates would be promising for efficient emulsion-based delivery systems.

Lactoferrin-chia seed mucilage complex coacervates for intestinal delivery of quercetin and fortification of set yogurt

This study aimed to develop complex coacervates utilizing lactoferrin (LF) and chia seed mucilage (CSM) for promoting intestinal delivery of quercetin (Q) and fortification of set yogurt. Three cross-linkers, including calcium chloride (CC), transglutaminase (TG), and polyphenolic complex (HP), were used to further reinforce the coacervate network. Cross-linked coacervates had higher values of coacervate yield, encapsulation efficiency, and loading capacity. They efficiently preserved Q under gastric condition (⁓87%–99%), with CSM-TG-Q-LF being most effective for intestinal delivery of Q. Moreover, digested pellets of the cross-linked coacervates displayed better antioxidant activity than the uncross-linked coacervates with CSM-TG-Q-LF pellets showing maximum bioactivity. The Q-loaded coacervates demonstrated superior assembly in the yogurt matrix compared to the unencapsulated Q. Moreover, the coacervate systems, especially CSM-TG-Q-LF significantly improved the textural properties of yogurt and the stability of Q in it. Therefore, CSM-TG-LF is a promising carrier to promote intestinal delivery and food application of hydrophobic molecules.

Ascorbic acid encapsulation by complex coacervation of kappa carrageenan and calcium caseinate pretreated by high‐power ultrasound

AbstractEncapsulation by coacervation has received interest in the last few years because of its low cost. Ultrasound (US) processing has proven to be an adequate technology for protein denaturation, increasing coacervation yield. There is a lack of information regarding its effects on encapsulation yield. The aim of this work was to evaluate the effect of US treatments on calcium caseinate (CaCN)–kappa carrageenan (KC) coacervates and the improvements in encapsulation efficiency (EE) of ascorbic acid (AA). US‐treatments (50% and 100% amplitude, 2 and 4 min) were applied to a 2% CaCN solution. Caseinate solution was mixed with a soy oil–AA (25%) W/O emulsion to form a second emulsion W/O/W. Finally, the second emulsion was employed for complex coacervation with KC (2% solution). The results showed a 10% increase in EE in the US‐treatments, with better stability and release profiles compared to the control. Sonication proved to be effective for coacervation improvement.Practical ApplicationsUltrasound pretreatment of calcium caseinate for coacervation along with kappa carrageenan showed an increase in the coacervation yield. This result was mainly attributed to the structural protein modification obtained after ultrasound (US) treatment. These coacervates can be employed to encapsulate bioactive compounds, such as ascorbic acid (AA), which is one of the most labile vitamins. In this sense, the US application leads to increases in encapsulation efficiency (around 10%) with a better stability and release profile than the capsules without treatment. These results create an opportunity to encapsulate AA and use the capsules in systems with a wide range of pH, increasing the chances of having functional products on the market.

Preparation of sodium-containing coacervates via high-voltage electrostatic field treatment: Saltiness perception of prefabricated chicken patties

Sodium-containing soy protein isolates (SPI)/apple pectin (AP) coacervate dispersion were prepared via high-voltage electrostatic field (HVEF) application to inhomogeneous spatial distribution of sodium as a strategy for reduction of salt content and enhancing the saltiness of prefabricated chicken patties. SPI/AP coacervates were prepared by HVEF processing at pH of 4.0, HVEF voltage of 32 kV, and ratio of SPI: AP to 5:1 which was optimized according to Artificial neural network (ANN)-coupled with genetic algorithm. Fluorescence intensity and FTIR analysis demonstrated that the HVEF treatment caused alteration of protein conformation, improved hydrogen bonding and electrostatic interactions between SPI and AP. At the NaCl concentration of 100 mM, HVEF treated sodium-containing SPI/AP coacervates achieved maximum phase separation as well as coacervate yield (85.23 ± 0.51%). HVEF treated sodium-containing SPI/AP coacervates displayed increased sodium fluorescence intensities, higher sodium concentration difference between coacervate phase and supernatant, and smaller particle sizes. Furthermore, HVEF treated coacervate dispersion showed higher sodium release in vitro during oral digestion. The saltiness of prefabricated chicken patties prepared using HVEF treated coacervates dispersion allowed a reduction in the sodium content of 43.59%. The increase of saltiness perception and sodium release in prefabricated chicken patties is attributed to enhanced water mobility in the matrix and distribution of inhomogeneous sodium.

Does the protein structure of β-lactoglobulin impact its complex coacervation with type A gelatin and the ability of the complexes to entrap lutein?

The heteroprotein complex coavervation (HPCC) is triggered by the interaction between oppositely charged proteins resulting in two liquid phases in equilibrium: the coacervate phase, which is rich in protein and the equilibrium solution which has low protein concentration. Several intrinsic and extrinsic factors affect the HPCC, including the nature and the conformational state of the involved proteins. In this work, the mechanism of complex coacervation between type A gelatin (GA) and native and thermal treated (70 °C/5 min) β-lactoglobulin (β-lg and β-lg (TT)) was investigated. In addition, the ability of the obtained complex coacervates to entrap lutein was evaluated. The applied thermal treatment led to an increase of about 20% in the concentration of surface free sulfhydryl groups and increased around 66% the surface hydrophobicity of β-lg (TT), compared with the untreated one. Nevertheless, minor impact was noticed in the aggregation state of the proteins, as well as in their ability to bind lutein (Ksv in the magnitude order of 104 M−1). The optimal condition for the complex coacervation between GA-β-lg and GA-β-lg (TT) was pH 6.5, minimal ionic strength and mass ratio of 2.5:1. Even if the applied thermal treatment did not promote important changes in the thermodynamic parameters of the molecular interaction between GA-β-lg (TT) compared with those for the molecular interaction between GA-β-lg, it negatively affected the coacervation yield (from 64% to 57% in the optimal condition). Both obtained complex coacervates exhibited high lutein entrapment efficiency, demonstrating their potential for protecting and delivering this bioactive compound.

Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin

Heteroprotein complex coacervation is an assembly formed by oppositely charged proteins in aqueous solution that leads to liquid-liquid phase separation. The ability of lactoferrin and β-lactoglobulin to form complex coacervates at pH 5.5 under optimal protein stoichiometry has been studied in a previous work. The goal of the current study is to determine the influence of ionic strength on the complex coacervation between these two proteins using direct mixing and desalting protocols. The initial interaction between lactoferrin and β-lactoglobulin and subsequent coacervation process were highly sensitive to the ionic strength. No microscopic phase separation was observed beyond a salt concentration of 20 mM. The coacervate yield decreased drastically with increasing added NaCl from 0 to 60 mM. The charge-screening effect induced by increasing the ionic strength is attributed to a decrease of interaction between the two oppositely charged proteins throughout a decrease in Debye length. Interestingly, as shown by isothermal titration calorimetry, a small concentration of NaCl around 2.5 mM promoted the binding energy between the two proteins. These results shed new light on the electrostatically driven mechanism governing the complex coacervation in heteroprotein systems.

Phase separation and formation of sodium caseinate/pectin complex coacervates: effects of pH on the complexation

BackgroundThe electrostatic interactions between polysaccharides and proteins are an interesting field in the complex coacervation. PH and mixing ratio have major effect on the complexation and the coacervates structure. Hence, it is necessary to find the optimum pH and mixing ratio of the coacervates as well as understanding the thermal, mechanical, and structural characterization of the coacervates. Thus, structural changes of the complexes of sodium caseinate (NaCas) and high methoxyl pectin as a function of pH (2.00–7.00), biopolymer ratios (1:1, 2:1, 4:1, and 8:1), and total biopolymer concentration (0.1, 0.2, and 0.4% w/v) were evaluated by light scattering and ζ-potential measurements. The phase separation behavior of the NaCas/HMP coacervate and its kinetics turbidity were also investigated via monitoring the turbidity profiles. Moreover, the thermal, rheological and structural behavior of the coacervates was evaluated at the selected pH values.ResultsThe highest turbidity, particle size, and viscosity were achieved at pHmax = 3.30 and formation or dissociation around the pHmax was confirmed by particle size and FTIR. The optimum condition for the coacervation of NaCas and HMP was obtained at ratio 4:1 and 0.4% w/v. Thermal and mechanical stability of the NaCas/HMP coacervates was improved at pH 3.30. By increasing the total concentration of biopolymers, the NaCas/pectin ratio shifted to higher pH values. Furthermore, the maximum coacervate yield was achieved at 39.8% w/w at a ratio of 4:1 of NaCas/HMP and a total biopolymer concentration of 0.4% w/v.ConclusionPhase separation behavior of the coacervates exhibited the optimum pH in coacervation between NaCas and HMP. Furthermore, the rheological, thermal and structural stability of the coacervates were improved in comparison with the single biopolymers.Graphical

Microencapsulation of red beet extract using chitosan‐Persian gum complex coacervates

AbstractThe coacervation technique is an efficient encapsulation process in which macromolecules with opposite surface charges interact, resulting in polymeric complexes. Hydroethanolic solvent (52%) was selected to obtain bioactive compounds from red beet using the mixture experimental design. Red beet extract was encapsulated in a complex of chitosan and negatively charged Persian gum. The optimum condition for coacervate formation was received at the chitosan to Persian gum ratio of 18:82 at pH 5.3. The coacervation yield of the two polysaccharides was 80%, and the zeta potential of dispersion was close to zero. Complex formation between two biopolymers was confirmed through FTIR. Micro‐sized coacervates showed 90% encapsulation efficiency for the betalain extract to coacervate dispersion ratio of 14.3%. The betalain‐loaded chitosan/Persian gum complex presented superior thermal stability compared with pure polysaccharides. The obtained complex can be applied to improve the stability of betalains and control their release in food and pharmaceutical applications.Novelty Impact StatementEqual mixture of water:ethanol resulted in maximum betalain extraction. Strong electrostatic complexation was approved between Persian gum and chitosan. Persian gum/chitosan coacervate demonstrated high loading capacity for betalains.

Structural, morphological and rheological characterisation of bovine serum albumin–cress seed gum complex coacervate

SummaryThe interactions between the bovine serum albumin (BSA) and cress seed gum (CSG) were investigated by structural, morphological and rheological characterisation as a function of pH level (7.0–2.0) and biopolymers’ concentrations (BSA, 0.1%, 0.5% and 1%, w/w and CSG, 0.01%, 0.05% and 0.1%, w/w). The results showed that turbidity, zeta potential and coacervate yield values had correlations with the initial number of biopolymers, which are influenced by the level of the positive and negative charges of BSA and CSG. Furthermore, the optimal complexation conditions in terms of pH, CSG‐BSA content and yield were 3.5%, 0.05–0.1% and 61.17% respectively. Rheological properties revealed the formation of a weakly gel‐like structure with a shear‐thinning behaviour. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) authenticated an amorphous and branch‐like network structure in the coacervate phase respectively. These results reflect that CSG‐BSA complex coacervate could be an appropriate biopolymer carrier for susceptible and bioactive compounds.

Microencapsulation of algae oil by complex coacervation of chitosan and modified starch: Characterization and oxidative stability

The formation of complex coacervation using chitosan and octenyl succinic anhydride modified starch (OSA starch) and microencapsulation of algae oil were investigated in this study. The zeta-potential, turbidity and coacervate yield were evaluated as a function of pH and the chitosan- OSA starch mass ratio. The highest coacervate yield was achieved at pH 6.0 with a chitosan to OSA starch ratio of 1:3 (w/w). Isothermal titration calorimetry (ITC) indicated favorable affinity (Ka = 1.51 × 105 M−1) between chitosan and OSA starch. The microcapsules yielded an encapsulation efficiency (EE) in the range of 42.8 ± 0.8%- 93.1 ± 1.2%, the loading capacity ranged between 30.4 ± 2.7% and 58.3 ± 1.3%. Fourier transform infrared spectroscopy (FT-IR) spectra and scanning electron microscopy (SEM) further confirmed the microencapsulation. In comparison with the bulk oil, the microencapsulated algae oil exhibited improved oxidative stability during storage.

Preparation and characterization of soybean Protein isolate/chitosan/sodium alginate ternary complex coacervate phase

To improve morphological structure and stability of soy protein isolate - chitosan coacervate, a soy protein isolate-chitosan-sodium alginate ternary complex coacervate phase was successfully constructed by adding sodium alginate. The ζ -potential and turbidity data showed that soy protein isolate, sodium alginate, and chitosan interacted with each other in the pH range 5.0–7.0. The highest ternary coacervate yield was obtained at soy protein isolate/sodium alginate ratio 12:1 (g/g), soy protein isolate/sodium alginate:chitosan ratio 4:1 (g/g), pH 6.5, and total biopolymer concentration of 5 g/L. The viscoelastic properties and microstructure were also studied using rheology, fourier transform infrared spectroscopy, texture profile analysis, and scanning electron microscopy, which indicated that the ternary coacervates prepared in pH 5.5, 6.0, and 6.5 had a viscoelastic solid behavior (storage moduli between 12,600 and 35,000 Pa; loss moduli between 3440 and 10,000 Pa) with honeycomb porous network structures. The ternary coacervate prepared at pH 6.5 was more compact and clearly porous. The stability of the ternary complex coacervate phase to pH and ionic strength slight increased. The in situ cross-linking of sodium alginate can improve the structure properties of ternary coacervates, which may provide a new carrier to incoporate bioactive ingredients into food products.

Formulation, spray-drying and physicochemical characterization of functional powders loaded with chia seed oil and prepared by complex coacervation

In this research, complex coacervation between soy protein isolate (SPI) and gum arabic (GA) constituted a preliminary step for developing chia oil (CO)-in-water emulsions suitable for subsequent spray-drying. The contributions of total biopolymer concentration, SPI-GA ratio w/w and ionic strength on coacervate yield (CY) were quantified through a 3×6×4 factorial design. The SPI-GA ratios that gave the highest CY values (1-1 and 2-1) were selected to prepare emulsions and blank dispersions (devoid of CO). The preparation process included four well-defined sequential steps: high speed homogenization, high pressure homogenization, complex coacervation and a carrier addition (maltodextrin). The emulsification step, the SPI-GA ratio and the presence of CO had a significant effect (p ≤ 0.05) on ζ-Potential, apparent viscosity, structural recovery of the systems, gel strength and cross-linking. The microencapsulation process preserved the quality of CO (2.18 ± 0.01 h), as reflected by enhanced oxidative stability indices (around three times higher than bulk CO, 5.65–6.84 h) and non-significant changes in α-Linolenic acid after spray-drying and in-vitro digestion processes (60–66.53%, relative abundance). In addition, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) helped corroborate the stability of CO within the powders' structure. Finally, different characteristics of powders were significantly influenced (p ≤ 0.05) by the presence of CO, especially the color, flowability and sorption-dependent properties: the monolayer content (Wm) and the bulk moisture diffusivity.

Complex coacervate formation between hemp protein isolate and gum Arabic: Formulation and characterization

In this study, intermolecular interactions and structure formation between hemp protein isolate (HPI) and gum Arabic (GA) were investigated to unravel their complexation mechanisms. For this purpose, structural transition as a function of pH (2.0–7.0) and protein to polysaccharide ratio (HPI:GA, R = 0.5:1–13:1 w/w) was evaluated via turbidimetric analysis, ζ-potentiometry, state diagram construction and coacervate yield. It was proved that critical phase transition pH shifted to higher values with R increase, until reaching a plateau at ratio 10:1, with complexes to be formed even at pH region where both biopolymers were negatively charged. The shift of pH value, where maximum turbidity was noticed (pHopt), was well in accordance with net charge neutrality of HPI-GA mixtures found by electrophoretic mobility measurements. Maximum coacervation, occurred at ratio R = 2:1 and pHopt = 3.5, was depicted by the highest yield (92%), while morphological characteristics of liquid as well as freeze-dried HPI-GA coacervates, obtained through optical and scanning electron microscope measurements, gave a further perception of the associative processes during complex coacervation. Additionally, the molecular interactions between HPI and GA were confirmed by Fourier transform infrared spectroscopy (FTIR) revealing primarily electrostatic interactions with secondary stabilization of hydrogen bonds. Therefore, these findings could provide useful information for the development of HPI – GA coacervates as a potential bioactive encapsulation means.

Complex coacervation of pea protein isolate and tragacanth gum: Comparative study with commercial polysaccharides

The ability of pea protein isolates (PPI) to form complex coacervates with tragacanth gum was investigated. The coacervate formation was structurally compared to three other PPI-polysaccharide interaction models: arabic gum and sodium alginate (known to form coacervates with PPI) and tara gum, a galactomannan. The effects of the pH and protein/polysaccharide ratio were mainly investigated using turbidity and zeta potential measurements. Regarding the pH of soluble complex formation, the pH of complex coacervates increased with the increase in protein-anionic polysaccharide mixture ratio. SEM images revealed the ability of the spray-drying process to form spherical particles of pea protein-polysaccharide complexes. The specificity of the microparticle surface was protein-dependent. FTIR analyses of coacervates showed the electrostatic interaction between the PPI and the polysaccharides. The results showed that tragacanth gum could be used as an alternative to gum arabic to form complex coacervates with PPI based on zeta potential measurements and coacervation yield studies.

Complex coacervation of carboxymethyl konjac glucomannan and ovalbumin and coacervate characterization

Carboxymethyl konjac glucomannan (CMKGM) is an anionic derivative of konjac glucomannan (KGM). Its coacervation with ovalbumin (OVA) was investigated through turbidity and coacervate yield measurements and the resultant CMKGM-OVA coacervates were characterized as a function of phase separation pH. The results indicated that CMKGM could coacervate with OVA in pHs ranging from 2.0 to 4.5. OVA to CMKGM mass ratios higher than 1:1 led to insoluble coacervates, while lower ratios conferred soluble complexes. NaCl suppressed the interaction between CMKGM and OVA and could resuspend their precipitated coacervates. The interaction between the two polyelectrolytes was not affected in temperatures ranging from 25 °C to 55 °C, but was weakened in higher temperatures. The coacervation increased the thermal stability and induced structural changes in both the polyelectrolytes. Atomic force microscope observation revealed that the CMKGM-OVA coacervates separated in mass ratio 1:1 was not susceptible to aggregation, and quartz crystal microbalance with dissipation analysis demonstrated that OVA exhibited the strongest absorption towards CMKGM in pH 3.0 in multilayer mode. Hence, CMKGM is a promising polyelectrolyte for coacervation with proteins and could be used in the construction of targeted delivery systems through the electrostatic interaction with oppositely charged biopolymers.