Associative Phase Behavior and Negative Second-Order Virial Coefficients in Analytical Calculations of the Spinodal for Complex Mixtures Composed of Many Components.

The calculation of spinodals for mixtures composed of many macromolecular components ( ≥ 2, not counting the solvent explicitly as a component) for a model including interactions up to quadratic terms in concentration is extended to the case of negative (second-order) virial coefficients, typically indicating attractive interactions between the components. Surprisingly, it is found that different permutations of the signs of the virial coefficients do not always lead to different spinodals. This observation is explained by means of an analysis of the effects of the signs of the virial coefficients in calculations in a parameter space introduced previously as "linear programming space", in which calculations for the spinodal can be done efficiently.

Phase Separation in Complex Mixtures with Many Components: Analytical Expressions for Spinodal Manifolds.

The phase behavior is investigated for systems composed of a large number of macromolecular components , with ≥ 2. Liquid-liquid phase separation is modeled using a virial expansion up to the second order of the concentrations of the components. Formal analytical expressions for the spinodal manifolds in dimensions are derived, which simplify their calculation (by transforming the original problem into inequalities that can be evaluated numerically using linear programming techniques).

Phase Behavior of Ternary Polymer Mixtures in a Common Solvent.

The Edmond-Ogston model for phase separation is extended to ternary polymer mixtures in a common solvent (de facto a quaternary mixture). The model assumes a truncated virial expansion of the Helmholtz free energy up to the second-order terms in the concentration of the polymers, and the second virial coefficients (, , , , , ) are the six parameters of the model. New results from this model are presented in relation to earlier work on binary mixtures: a necessary condition for the virial coefficients for the occurrence of phase separation in two or three phases, an analysis of the different regions of (local) thermodynamic instability using the Descartes sign rule, an expression for the critical curves, a relation between the tangents in points along the critical curve, a relation between the concentration of components in the different phases according to the so-called Lambert-W function, and a consistency check for the composition of coexisting phases in ternary mixtures.

Exploring how changes to the steroidal core alter oleogelation capability in sterol: γ-oryzanol blends.

Oleogels based on sterols such as β-sitosterol blended with the sterol ester γ-oryzanol are a very interesting class of systems, but there are aspects of their formation and structure that remain elusive. It has previously been shown that a methyl group on the C30 position of the sterol-ester plays an important role in gelation. This work explored the effect that having C30 methyl groups on both the sterol and the sterol-ester had on the gelation process and subsequent gel structure.

Erratum: Addition to "Phase-Separating Binary Polymer Mixtures: The Degeneracy of the Virial Coefficients and Their Extraction from Phase Diagrams".

[This corrects the article DOI: 10.1021/acsomega.1c00450.

Phase-Separating Binary Polymer Mixtures: The Degeneracy of the Virial Coefficients and Their Extraction from Phase Diagrams.

The Edmond-Ogston model for phase separation in binary polymer mixtures is based on a truncated virial expansion of the Helmholtz free energy up to the second-order terms in the concentration of the polymers. The second virial coefficients ( , , ) are the three parameters of the model. Analytical solutions are presented for the critical point and the spinodal in terms of molar concentrations.

The Phase Behavior of γ-Oryzanol and β-Sitosterol in Edible Oil.

The phase behavior of binary mixtures of γ-oryzanol and β-sitosterol and ternary mixtures of γ-oryzanol and β-sitosterol in sunflower oil was studied. Binary mixtures of γ-oryzanol and β-sitosterol show double-eutectic behavior. Complex phase behavior with two intermediate mixed solid phases was derived from differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) data, in which a compound that consists of γ-oryzanol and β-sitosterol molecules at a specific ratio can be formed.

Elucidation of density profile of self-assembled sitosterol + oryzanol tubules with small-angle neutron scattering.

Small-angle neutron scattering (SANS) experiments have been performed on self-assembled tubules of sitosterol and oryzanol in triglyceride oils to investigate details of their structure. Alternative organic phases (deuterated and non-deuterated decane, limonene, castor oil and eugenol) were used to both vary the contrast with respect to the tubules and investigate the influence of solvent chemistry. The tubules were found to be composed of an inner and an outer shell containing the androsterol group of sitosterol or oryzanol and the ferulic acid moieties in the oryzanol molecule, respectively.

Stability of aqueous food grade fibrillar systems against pH change.

We report that the stability of an aqueous food grade fibril system upon pH change is affected by the presence of peptides that are formed during the process of fibril formation. We discuss several other relationships between food relevant properties and nano-scale characteristics, and compare these relationships for aqueous fibril systems to those of oil based fibril systems. In such fibril systems, dynamics, self-organisation, and sensitivity to external conditions, play an important role.

Organogel-emulsions with mixtures of β-sitosterol and γ-oryzanol: influence of water activity and type of oil phase on gelling capability.

In this study, water-in-oil emulsions were prepared from water containing different salt concentrations dispersed in an oil phase containing a mixture of β-sitosterol and γ-oryzanol. In pure oil, the β-sitosterol and γ-oryzanol molecules self-assemble into tubular microstructures to produce a firm organogel. However, in the emulsion, the water molecules bind to the β-sitosterol molecules, forming monohydrate crystals that hinder the formation of the tubules and resulting in a weaker emulsion-gel.

The Influence of Concentration and Temperature on the Formation of γ-Oryzanol + β-Sitosterol Tubules in Edible Oil Organogels.

The gelation process of mixtures of γ-oryzanol and sitosterol structurants in sunflower oil was studied using light scattering, rheology, and micro-scanning calorimetry (Micro-DSC). The relation between temperature and the critical aggregation concentration (CAC) of tubule formation of γ-oryzanol and sitosterol was determined using these techniques. The temperature dependence of the CAC was used to estimate the binding energy and enthalpic and entropic contribution to the tubular formation process.

Effect of hydrolysed egg protein on brain tryptophan availability.

Serotonin synthesis critically depends on plasma levels of tryptophan (TRP). Earlier studies have shown that for mood and cognitive benefits to occur, the ratio between TRP and other large neutral amino acids (LNAA) has to be increased by approximately 40 %. The present study investigated the dose-dependent effects of a TRP-rich hydrolysed protein (egg-protein hydrolysate, EPH) on the plasma TRP:LNAA.

Multicomponent hollow tubules formed using phytosterol and gamma-oryzanol-based compounds: an understanding of their molecular embrace.

The formation kinetics of self-assembling tubules composed of phytosterol:gamma-oryzanol mixtures were investigated at the Canadian Light Source on the mid-IR beamline using synchrotron radiation and Fourier transform infrared spectroscopy (FT-IR). The Avrami model was fitted to the changing hydrogen bonding density occurring at 3450 cm(-1). The nucleation process was found to be highly dependent on the molecular structure of the phytosterol.

Manipulation of glycemic response with isomaltulose in a milk-based drink does not affect cognitive performance in healthy adults.

Previous research suggests that glucoregulation and nutrient interventions, which alter circulating glucose, impact cognitive function. To examine the effect of modulating glycemic response using isomaltulose on cognitive function 24 healthy male adult participants consumed energy and macronutrient-matched milk-based drinks containing 50 g isomaltulose, 50 g sucrose or a water control in a counterbalanced within-subject design. Interstitial glucose was measured continuously in 12 subjects and all provided 9 capillary measures on each test day.

Stability of whey-protein-stabilized oil-in-water emulsions during chilled storage and temperature cycling.

The stability of heat-treated and/or acidified, partly-crystalline-fat-based, whey-protein-stabilized oil-in-water (o/w) emulsions against partial coalescence was investigated during chilled storage (at 5 degrees C) and repeated temperature cycling (three times between 5 and 25 degrees C). Experiments focused on the evolution of firmness and droplet size (using pulsed field gradient NMR and scanning electron microscopy). Besides the effects of denaturation and/or acidification, the influence of the droplet size of the dispersed phase on emulsion stability was investigated also.