Agarose gel isoelectric focusing of gliadins in the presence of ethanol

Stenram, Unna; Acevedo, Fernando; Larsson-Raźnikiewicz, Märtha

doi:10.1016/0308-8146(90)90070-k

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…For a diluted agarose solution in water containing 6% ethanol, the mesoscopic aggregates observed are more compact in morphology due to the modification of the balance between H-bonds and hydrophobic interactions [5]. In another way, ethanol is used for the coagulation of agarose/DMSO for fibers production [12], and an isoelectric focusing technique was applied for the characterization of gliadins [28] in 45% ethanol for a better resolution. The authors assert that this composition is the highest possible ethanol concentration that does not cause the precipitation of agarose.…”

Section: Comparison Of Gels In Water and Ethanolmentioning

confidence: 99%

Characterization of Agarose Gels in Solvent and Non-Solvent Media

et al. 2023

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Agarose is known to form a homogeneous thermoreversible gel in an aqueous medium over a critical polymer concentration. The solid-liquid phase transitions are thermoreversible but depend on the molecular structure of the agarose sample tested. The literature has mentioned that agarose gels could remain stable in non-solvents such as acetone or ethanol. However, there has been no characterization of their behavior nor a comparison with the gels formed in a good solvent such as water. In the first step of this article, the structure was characterized using 1H and 13C NMR in both D2O and DMSO-d6 solvents. DMSO is a solvent that dissolves agarose regardless of the temperature. First, we have determined a low yield of methyl substitution on the D-galactose unit. Then, the evolution of the 1H NMR spectrum was monitored as a function of temperature during both increasing and decreasing temperature processes, ranging from 25 to 80 °C. A large thermal hysteresis was obtained and discussed, which aided in the interpretation of rheological behavior. The hysteresis of NMR signals is related to the mobility of the agarose chains, which follows the sol/gel transition depending on the chains’ association with H-bonds between water and the -OH groups of agarose for tightly bound water and agarose/agarose in chain packing. In the second step of the study, the water in the agarose gel was exchanged with ethanol, which is a non-solvent for agarose. The resulting gel was stable, and its properties were characterized using rheology and compared to its behavior in aqueous media. The bound water molecules that act as plasticizers were likely removed during the exchange process, resulting in a stronger and more brittle gel in ethanol, with higher thermal stability compared to the aqueous gel. It is the first time that such gel is characterized without phase transition when passing from a good solvent to a non-solvent. This extends the domains of application of agarose.

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Section: Comparison Of Gels In Water and Ethanolmentioning

confidence: 99%

Characterization of Agarose Gels in Solvent and Non-Solvent Media

et al. 2023

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“…For a diluted agarose solution in water containing 6% of ethanol, mesocopic aggregates observed are more compact in morphology due to modification of the balance between H-bonds and hydrophobic interactions [2]. On another way, ethanol is used for coagulation of agarose /DMSO for fibers production [9] and in isoelectric focusing technique was applied for characterisation of gliadins [25] in 45% ethanol for a better resolution. The authors precise that this composition is the highest possible ethanol concentration not causing precipitation of agarose.…”

Section: Comparison For Gels In Water and In Ethanolmentioning

confidence: 99%

Characterisation of Agarose Gels in Solvent and Non-solvent Media

Roux¹,

Jeacomine²,

Maîtrejean³

et al. 2023

Preprint

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Agarose is known to form a homogeneous thermoreversible gel in aqueous medium over a critical polymer concentration. The solid-liquid phase transitions are thermoreversible but depend on the molecular structure of the agarose sample tested. Then, in a first step, the structure was characterised by 1H and 13C NMR in D2O and in DMSO which is a solvent of agarose whatever the temperature. A low yield in methyl substituent on the D-galactose unit was determined. Then, evolution of the 1H NMR spectrum was followed as a function of temperature in increasing and decreasing temperature process from 25 to 80°C. A large thermal hysteresis is obtained and discussed. It helps to interpret rheological behaviour. In fact, NMR signals are related to proton relaxation and especially to proton involved in H-bonds between water and -OH agarose for tightly bound water and agarose/agarose in chain packing. In a second step, water was exchanged against ethanol which is a non solvent of agarose. A stable gel was demonstrated and characterised by rheology to be compared with aqueous behaviour. Bound water playing the role of plasticizer is probably removed and the gel is much stronger (and brittle) in ethanol with a larger thermal stability. It is the first time that such gel is characterised without phase transition when passing from a good-solvent to a non-solvent. This extends the domains of application of agarose.

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Electrophoresis of cereal storage proteins

Bean

Lookhart

2000

Journal of Chromatography A

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Agarose gel isoelectric focusing of gliadins in the presence of ethanol

Cited by 3 publications

References 7 publications

Characterization of Agarose Gels in Solvent and Non-Solvent Media

Characterization of Agarose Gels in Solvent and Non-Solvent Media

Characterisation of Agarose Gels in Solvent and Non-solvent Media

Electrophoresis of cereal storage proteins

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