Influence of Levan on the Thermally Induced Gel Formation of β-Lactoglobulin

Abstract

In this study, the influence of levan on the phase behavior and the thermally induced gelation of the mixed β-lactoglobulin—levan gels as a function of polymer content, molecular weight and ionic strength was characterized. For this purpose, rheology was used to study the mechanical properties of the gels and the water binding of the network structure was investigated by time domain nuclear magnetic resonance. Phase behavior and network type were analyzed by optical observation and electron microscopy. Levan enhanced the aggregation and gel formation of β-lg due to segregative forces between the polymer species. Segregation was caused by the excluded volume effect and was more pronounced at lower ionic strength, higher levan contents and higher levan molecular weights. The presence of levan increased the water binding of the gel networks. However, this effect decreased with increasing levan content. At high ionic strength and high levan content, phase separated gels were formed. While segregative forces enhanced network formation, and therefore, increased the gel strength of mixed gels at low ionic strength, levan had also antagonistic effects on the network formation at high ionic strength and high polymer contents.

Unveiling the Rational Development of Stimuli-Responsive Silk Fibroin-Based Ionogel Formulations

“…We suggest that IL inclusion promotes the formation of diverse ionogels via electrostatic, inter- and intramolecular hydrogen bonding interactions. ,, We consider that for the [Cho]­[Cl]-ionogel formulations, of highest ionic strength, [Cho]­[Cl] incorporation could result in surface charge accumulation on the silk fibroin chains and weak intermolecular hydrogen bonding interactions. ,− This would explain our findings of higher T ionogel values, lower phenobarbital solubility, and impeded [Cho]­[Cl]-ionogel formation. In contrast, the extended structure of the dihydrogen phosphate anions could contribute to the formation of strong intermolecular hydrogen bonding networks and steric effects. − This aligns with our observations of a shorter formation period, greater strength, structural and energetic stability for the [Cho]­[DHP]-ionogels compared to the [Cho]­[Cl]-ionogels.…”