Rheological and structural characterization of agar/whey proteins insoluble complexes

Rocha, Cristina M. R.; Souza, Hiléia K.S.; Magalhães, Natália F.; Andrade, Cristina T.; Gonçalves, M. P.

doi:10.1016/j.carbpol.2014.04.015

Cited by 40 publications

(11 citation statements)

References 46 publications

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“…The obtained zeta-potential values of the agar microgel particles were similar to those reported in previous studies, that is approximately −20 mV. 32,33 The BD-C and BD-80 particles prepared via macrogel formation indicated slightly lower zeta-potential magnitudes, which could be attributed to different structural features related to the surrounding state of sulfated groups on the surface of particles. All the absolute zeta-potential values were of about 20 mV, probably enough to generate electrically repulsive forces between particles helpful for preventing strongly binding aggregation.…”

Section: Resultssupporting

confidence: 86%

Microgelation imparts emulsifying ability to surface-inactive polysaccharides—bottom-up vs top-down approaches

et al. 2018

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In order to impart emulsifying ability to gel-forming polysaccharides that have not been used as emulsifying agents, three kinds of polysaccharides, agar, curdlan, and gellan gum were converted to microgels by different gelation methods via the bottom-up and top-down approaches. We clearly demonstrated that agar and curdlan acquired the ability to emulsify an edible oil by microgel formation. Among the colloidal properties of microgel suspensions such as microstructure, particle size, zeta-potential, viscosity, and surface hydrophobicity, we pointed out the importance of particle size on the emulsifying ability of polysaccharide-based microgels. The creaming behavior of the microgel-stabilized emulsions depended on the polysaccharide types and microgel preparation methods. The emulsion stability against oil droplet coalescence was extremely high for agar and curdlan microgel-stabilized emulsions during storage in the static condition, whereas different stability was observed for both the emulsions, that is, the curdlan microgel-based ones were more resistant to dynamic forcible destabilization by centrifugation than the agar ones, which can be attributed to the surface hydrophobicity of the microgels.

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Section: Resultssupporting

confidence: 86%

Microgelation imparts emulsifying ability to surface-inactive polysaccharides—bottom-up vs top-down approaches

et al. 2018

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“…These observations indicate that factors beyond electrostatic interactions, such as hydrogen bonding, might contribute to the rheological properties of OCC‐GA coacervates (Huang et al, 2015). Similarly, agar–whey protein coacervates formed in citrate buffer produced higher modulus values than coacervates formed in water (Rocha, Souza, Magalhães, Andrade, & Gonçalves, 2014). In this study, the contributions of electrostatic interaction and hydrogen bonding to WPI‐FG coacervate formation and rheological properties were studied to help resolve the above discrepancies.…”

Section: Resultsmentioning

confidence: 99%

Ionic strength and hydrogen bonding effects on whey protein isolate–flaxseed gum coacervate rheology

Shim

Reaney

2020

Food Science & Nutrition

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Whey protein isolate (WPI) was mixed with anionic flaxseed (Linum usitatissimum L.) gum (FG), and phase transition during coacervate formation was monitored. Effects of ionic strength and hydrogen bonding on coacervation of WPI‐FG system and corresponding rheological properties were investigated. During coacervate formation, structural transitions were confirmed by both turbidimetry and confocal laser scanning microscopy. Increasing ionic strength with sodium chloride (50 mM) decreased optical density (600 nm) at pHmax. Correspondingly, pHc and pHϕ1 decreased from pH 5.4 to 4.8 and from 5.0 to 4.6, respectively, while pHϕ2 increased from pH 1.8 to 2.4. Sodium chloride suppressed biopolymer electrostatic interactions and reduced coacervate formation. Adding urea (100 mM) shifted pHϕ1, pHmax, and pHϕ2 from 4.8, 3.8, and 1.8 to 5.0, 4.0, and 2.2, respectively, while pHc was unaffected. Optical density (600 nm) at pHmax (0.536) was lower than that of control in the absence of urea (0.617). This confirmed the role of hydrogen bonding during coacervate formation in the biopolymer system composed of WPI and FG. Dynamic shear behavior and viscoelasticity of collected coacervates were measured, and both shear‐thinning behavior and gel‐like properties were observed. Addition of sodium chloride and urea reduced ionic strength and hydrogen bonding, resulting in decreased WPI‐FG coacervate dynamic viscosity and viscoelasticity. The disturbed charge balance contributed to a loosely packed structure of coacervates which were less affected by altered hydrogen bonding. Findings obtained here will help to predict flaxseed gum behavior in protein‐based foods.

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“…In numerous examples, the elastic behavior dominates (i.e., the storage modulus (G') dominates) [8,61,137,138,171,175,[177][178][179][180], while in other coacervates the viscous or liquid-like behavior (i.e., the loss modulus (G") dominates) [95,103,171]. Meanwhile, there are other systems where a crossover is observed between the two regimes, with G" dominating at low frequencies, and G' dominating at higher frequencies [61,71,72,79,111,130,162,171].…”

Section: Frequency Sweepsmentioning

confidence: 99%

Linear viscoelasticity of complex coacervates

Liu

Winter

Perry

2017

Advances in Colloid and Interface Science

129

163

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Rheology is a powerful method for materials characterization that can provide detailed information about the self-assembly, structure, and intermolecular interactions present in a material. Here, we review the use of linear viscoelastic measurements for the rheological characterization of complex coacervate-based materials. Complex coacervation is an electrostatically and entropically-driven associative liquid-liquid phase separation phenomenon that can result in the formation of bulk liquid phases, or the self-assembly of hierarchical, microphase separated materials. We discuss the need to link thermodynamic studies of coacervation phase behavior with characterization of material dynamics, and provide parallel examples of how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics. We conclude by highlighting key areas of need in the field, and specifically call for the development of a mechanistic understanding of how molecular-level interactions in complex coacervate-based materials affect both selfassembly and material dynamics.

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Rheological and structural characterization of agar/whey proteins insoluble complexes

Cited by 40 publications

References 46 publications

Microgelation imparts emulsifying ability to surface-inactive polysaccharides—bottom-up vs top-down approaches

Microgelation imparts emulsifying ability to surface-inactive polysaccharides—bottom-up vs top-down approaches

Ionic strength and hydrogen bonding effects on whey protein isolate–flaxseed gum coacervate rheology

Linear viscoelasticity of complex coacervates

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