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OVA (ovalbumin)/CMC (sodium carboxymethylcellulose) nanoparticles are prepared by combining complex coacervation and thermal induction. The effect of different parameters on stability of OVA/CMC nanoparticles (different ratios, pH, temperature, salt concentration and storage time) is investigated. And then the loading and stabilizing mechanism of particles on curcumin are further analyzed. After heating, OVA and CMC in particle could further cross-linking and a highly salt-tolerant and ultra-long stable nanoparticle can be formed. OVA/CMC nanoparticle with the loose structure of wool ball could effectively load curcumin with the loading content and loading efficiency of 36.40 and 95.40%, 36.30 and 92.82%, 36.0 and 94.48% for the ratios of 1:2, 1:1 and 2:1, respectively. Curcumin-loaded of OVA/CMC nanoparticles show good DPPH· scavenging activity, Ferric-reducing ability and ABTS + scavenging activity compared with curcumin/water. The results can be useful for designing food and beverage particle with improving bioactive substances functional properties., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

After formation of the ovalbumin (OVA)-gum arabic (GA) complex coacervates, a more ordered crystal structure was obtained, and the protein denaturation temperature increased from 72 to 96 °C. GA can reduce the pH-induced conformational perturbations of ovalbumin. The presence of GA improved the stability of the α-helix and β-turn regions against pH, but showed less influence on the random coil and β-sheet domains. The complex coacervates showed the highest viscosity value at pH 3.7 compared with the other pH values tested (4.0, 3.4, 3.0, 2.7) due to the stronger interactions of OVA and GA. A large thixotropic loop was observed for the coacervate obtained at pH 3.7 compared with that obtained at pH 4.0. Moreover, the salt concentration and OVA:GA ratio influenced the rheological properties by affecting the structure and composition of the complexes. A stronger interaction between OVA and GA led to greater viscoelastic properties., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Natural biopolymer stabilized oil-in-water emulsions were formulated using ovalbumin (OVA), gum arabic (GA) solutions and their complexes. The influence of interfacial structure of emulsion (OVA-GA bilayer and OVA/GA complexes emulsions) on the physical properties and antimicrobial activity of thyme oil (TO) emulsion against Escherichia coli (E. coli) was evaluated. The results revealed that the two types of emulsions with different oil phase compositions remained stable during a long storage period. The oil phase composition had an appreciable influence on the mean particle diameter and retention of the TO emulsions. The stable emulsion showed a higher minimum inhibitory concentration (MIC), and the TO emulsions showed an improved long-term antimicrobial activity compared to the pure thyme oil, especially complexes emulsion at pH 4.0. These results provided useful information for developing protection and delivery systems for essential oil using biopolymer., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The formation of soluble and insoluble complexes between ovalbumin (OVA) and gum arabic (GA) polysaccharide was investigated under specific conditions (pH 1.0-7.0; temperature 4-55 °C; NaCl concentration 0-60mM; total biopolymer concentration 0.05-3.0 wt%) by turbidimetric analysis. For the 2:1 OVA:GA ratio and in the absence of NaCl, soluble and insoluble complexes were observed at pH 4.61 (pHφ1) and 4.18 (pHφ2), respectively, with optimal biopolymer interactions occurring at pH 3.79 (pHopt). Under the same conditions, OVA alone gave only a weak turbidity intensity (turbidity <0.03), whereas GA had none. As the temperature increased, critical pH values shifted toward lower pH, and the maximum turbidity value occurred at 25 °C. The region between pHφ1 and pHφ2 was narrowed and the electrostatic interactions became weaker with increasing NaCl concentration. The maximum turbidity value increased as the total biopolymer concentration increased until reaching a critical value (2.0%), afterwards becoming a constant value., (Copyright © 2013. Published by Elsevier B.V.)

In this work, three methods were used for preparation of the emulsion. The mean particle diameter, ζ-potential, microstructure and stability of the emulsions coated by ovalbumin (OVA) and gum arabic (GA) were evaluated. The complexes (OVA/GA) and multilayer (OVA-GA) emulsions showed smaller droplet diameter (about 330 nm) above pH 3.3 and had a relatively good storage stability compared to the multilayer (GA-OVA) emulsion. Meanwhile, different stabilization mechanisms were identified. In the complexes (OVA/GA) emulsions, the OVA and GA formed complexes firstly that created an interface layer on the surface of the droplets. For the multilayer (OVA-GA) emulsion, the OVA adsorbed on the surface of the droplets, and then GA formed a double-layer structure by electrostatic interaction between the GA and the OVA. The multilayer (GA-OVA) emulsions showed a larger mean particle diameter due to the poor adsorption capacity of the GA compared with OVA. All emulsions revealed good thermal stability and no obvious change was observed. The experimental results demonstrated that the OVA/GA complexes could be used to prepare stable emulsion structures, which may be useful in the beverage industry. [ABSTRACT FROM AUTHOR]

The stability, rheological and morphology properties of oil-in-water emulsions coated by ovalbumin (OVA)/gum arabic (GA) complexes were evaluated. At a ratio of 1:2, the emulsions showed better creaming and oxidative stability. Above or below 1:2, the emulsions were unstable due to depletion or bridging flocculation and the rates of lipid oxidation for 30-day storage were significantly higher. All emulsions exhibited elastic gel-like rheological properties. But the apparent viscosity (η) and storage modulus (G′) of emulsions at a ratio of 1:2 were higher than that of 1:1 and 1:3, which attributed to the electrostatic repulsion and ordered spatial structure of emulsions. Meanwhile, the Raman spectral results showed the OVA/GA complexes stabilizing system induced lipid chain disorder or lipid–protein interactions modifications, which may reflect the formation of a gel-like structure in the emulsion. [ABSTRACT FROM AUTHOR]

This study investigated the complexes formed between ovalbumin (OVA) and gum arabic (GA) and their ability to stabilize oil-water emulsions. The stability of the emulsions stabilized by the OVA/GA complexes was evaluated by measuring storage time (1–7 days), salt concentration (0–100 mM NaCl), and heat (40–90 °C, 30 min) stability at pH 3.8–7.0. The results showed that the stability of the OVA-stabilized emulsion was greatly improved by an OVA/GA ratio of 1:2 and acidic pH. Above or below 1:2, the emulsion was unstable due to depletion or bridging flocculation. Emulsions saturated with OVA/GA complexes were stable with changing pH, storage time, and heat treatment (up to 90 °C). However, the OVA/GA complexes did not improve the stability of the emulsions when salt concentrations were varied. The experimental results demonstrated that OVA/GA complexes could be used to prepare stable emulsion structures, which may be useful in the beverage industry. [ABSTRACT FROM AUTHOR]

Phase separation behavior and structure between ovalbumin (OVA) and gum arabic (GA) were investigated at pH 1.5–6.5; 2:1 OVA:GA mixing ratio, total biopolymer concentration 0.05 wt%. Soluble and insoluble complexes were observed as a function of pH. The biopolymers particles had a tiny diameter ( d ≤ 500 nm) at pH above 4.0 or below 2.5, and increased sharply at pH 4.0 together with the turbidity under the same conditions. As the biopolymers mixing ratios increased from 1:3 to 24:1, critical pHs shifted towards higher pH. However, monovalent ions had a same influence on OVA–GA complex formation; the divalent cations reduced the formation of complex compared with same concentration monovalent ions. Second-derivative UV spectra and intrinsic fluorescence results indicated that the unfolding of the tertiary conformation was induced by GA, and more tryptophan residues were buried inside the OVA protein after complexation. [ABSTRACT FROM AUTHOR]

Abstract: The promotion or inhibition of gastrointestinal digestion of tea polyphenol (TP) towards the two typical proteins from egg white (ovalbumin (OVA) and lysozyme (LYZ)) was examined. The results showed that TP made OVA/LYZ easier for digestion in the pepsin solution at pH1.2 and inhibited OVA/LYZ digestion in pancreatin solution at pH7.5. Non-covalent interactions between OVA/LYZ and TP and the secondary structure of OVA/LYZ were studied by using Fluorescence spectroscopy and Fourier transform infrared spectroscopy (FTIR), respectively. Results suggested that stronger conformational change occurred at pH1.2 compared with that of pH7.5 affected by TP in both proteins. Non-covalent interactions between OVA/LYZ and TP at pH1.2 increased random and β-sheet structures in both proteins at the expense of α-helix, which resulted in the proteins with looser structures. At pH7.5, an opposite second structural change of both proteins caused by the non-covalent interactions between OVA/LYZ and TP. The conformational and second structural change of proteins (substrate) might be a reason for promoting and inhibiting digestion of OVA/LYZ affected by TP. [Copyright &y& Elsevier]

The emulsion stabilized by loose and branched particles was easy to flocculate and cream. And compact particles formed a stable interfacial membrane, which could resist hydrophobic interaction and flocculation. [Display omitted] • Relationship between particle characteristics and emulsion properties was analyzed. • Compactness and stability of particle depend on protein content in a certain range. • Compact particles could resist hydrophobic interaction and flocculation. • The important role of particle compactness in emulsion stability has been proved. A protein/polysaccharide colloidal particle was prepared via combined complex coacervation and heat-induction. When the ratio of ovalbumin (OVA) to carboxymethylcellulose (CMC) was at 1:2, loose flexible particles (low D f) with low surface hydrophobicity were obtained. Conversely, dense and compact particles (high D f) were easily formed at a higher OVA/CMC ratio. Only in the appropriate OVA/CMC ratio, pH will have a greater impact on the colloidal particles. At the pH value of 4.4, the OVA/CMC ratio had a greater impact on the colloidal particles compared to pH. The emulsion stabilized by loose particles had a mean particle size of 3888 nm and was easily flocculated and creamed. On the other hand, compact particles formed a stable emulsion, which had a higher exponent of Δ r2 (0.867) and could resist flocculation during the 7 days storage. As such, the results showed that stable emulsion could be realized by utilizing compact particles as emulsifiers. [ABSTRACT FROM AUTHOR]