An extension of the Pitzer equation for the excess Gibbs energy of aqueous electrolyte systems to aqueous polyelectrolyte solutions

Filho, Pedro de Alcântara Pessôa; Maurer, Gerd

doi:10.1016/j.fluid.2008.04.019

Cited by 19 publications

(5 citation statements)

References 31 publications

(66 reference statements)

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“…To calculate the molar concentrations the volume of proteins is excluded from the total volume of the gel, cf. ( Pessôa Filho and Maurer, 2008 ), similar to the Ross equation ( van der Sman, 2012 ).…”

Section: Theorymentioning

confidence: 90%

“…Furthermore, the ionic strength requires a redefinition for ions inside the gel phase. We follow the theory of Maurer for non-ideality of polyelectrolyte solutions ( Pessôa Filho and Maurer, 2008 ), which uses the Debye-Hueckel and Pitzer theory for the non-ideality of the ion and solvent activity, together with a redefinition of the ionic strength.…”

Section: Theorymentioning

confidence: 99%

“…Maurer argued that the ionic strength of a polyelectrolyte solution should be modified to include also the (partially) mobile charges on the polymer ( Pessôa Filho and Maurer, 2008 ). For our protein gel, it is defined as:

…”

Section: Theorymentioning

confidence: 99%

See 2 more Smart Citations

Physical chemistry of gastric digestion of proteins gels

Sman

Houlder

Cornet

et al. 2020

Current Research in Food Science

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In this paper, we present the rich physics and chemistry of the gastric digestion of protein gels. Knowledge of this matter is important for the development of sustainable protein foods that are based on novel proteins sources like plant proteins or insects. Their digestibility is an important question in the design of these new protein foods. As polyelectrolyte gels, they can undergo volume changes upon shifts in pH or ionic strengths, as protein gels experience when entering the gastric environment. We show that these volume changes can be modelled using the Flory-Rehner theory, combined with Gibbs-Donnan theory accounting for the distribution of electrolytes over gel and bath. In-vitro experiments of soy protein gels in simulated gastric fluid indeed show intricate swelling behaviour, at first the gels show swelling but at longer times they shrink again. Simulations performed with the Flory-Rehner/Gibbs-Donnan theory reproduce qualitatively similar behaviour. In the final part of the paper, we discuss how the model must be extended to model realistic conditions existing in the in-vivo gastric environment.

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Section: Theorymentioning

confidence: 90%

Section: Theorymentioning

confidence: 99%

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Physical chemistry of gastric digestion of proteins gels

Sman

Houlder

Cornet

et al. 2020

Current Research in Food Science

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“…It is assumed that all considered processes are isothermal at T = 25 °C, crystallisation is only induced via pH-variation and that pH variation in mixtures are instantaneous upon the implemented manipulation. The solubility of ampicillin as a function of pH is described using the extended Pitzer model (de Pessôa Filho et al, 2008) in Eqs. 1-2, where constants ε, σ, pKA1 and pKA2 are taken from the literature (Encarnación-Gómez et al, 2016), kB = Boltzmann constant, NA = Avogadro number, ρ = ampicillin density and the isoelectric point (pI) and its corresponding solubility (S(pI)) are regressed in previous work (Dafnomilis et al, 2019) log…”

Section: Batch Crystallisation Modelmentioning

confidence: 99%

Multi-objective Dynamic Optimisation of Ampicillin Batch Crystallisation

Dafnomilis

Diab

Rodman

et al. 2020

Computer Aided Chemical Engineering

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Ampicillin is a key β-lactam antibiotic listed as a World Health Organisation (WHO) Essential Medicine. Crystallisation is a unit operation of paramount importance in pharmaceutical manufacturing, whose design and operation are essential in controlling process yield and important product quality attributes, such as mean product crystal size (MCS) and size distribution width. A published model for the solubility of ampicillin as a function of pH as well as growth and nucleation kinetics is used towards the simulation and optimisation of its batch crystallisation. This study performs multi-objective dynamic optimisation of the batch crystallisation of ampicillin to establish optimal pH trajectories for different production objectives, including maximising the mean crystal size whilst minimising the size distribution width subject to various yield constraints. Trade-offs between different product quality attributes are thus quantified, visualised and discussed.

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“…Nevertheless, the real contribution of the protein to the ionic strength is still under debate, because the very de nition of the ionic strength is developed for punctual electric charges. One possible way to minimize this e ect is to use a similar approach that has been used for common polyelectrolytes (PESSÔA-FILHO;MAURER, 2008). Using such approach, it is possible to neglect this e ect here.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Study on the thermodynamics of bovine serum albumin aqueous solutions: experiments, modeling and molecular simulations.

Franco¹

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An extension of the Pitzer equation for the excess Gibbs energy of aqueous electrolyte systems to aqueous polyelectrolyte solutions

Cited by 19 publications

References 31 publications

Physical chemistry of gastric digestion of proteins gels

Physical chemistry of gastric digestion of proteins gels

Multi-objective Dynamic Optimisation of Ampicillin Batch Crystallisation

Study on the thermodynamics of bovine serum albumin aqueous solutions: experiments, modeling and molecular simulations.

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