1. Structure and dynamics of ovalbumin gels: 1. Gel induced by high-temperature heat treatment
- Author
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Akihiro Koike, Norio Nemoto, and Etsushiro Doi
- Subjects
Aqueous solution ,Polymers and Plastics ,Chemistry ,Organic Chemistry ,Evaporation ,Analytical chemistry ,Thermodynamics ,Dynamic mechanical analysis ,Viscoelasticity ,Shear modulus ,Creep ,Dynamic light scattering ,Dynamic modulus ,Materials Chemistry - Abstract
Dynamic viscoelastic (DVE) measurements are made on seven ovalbumin (OVA) gel samples induced by thermal denaturation of aqueous suspensions of OVA with OVA concentration C ranging from 12 to 45 wt% at 160°C for 5 min and subsequent moulding under pressure, and also on four OVA gels with higher C prepared by slow evaporation of water from the 45 wt% gel. The storage and loss shear moduli, G ′( ω ) and G ″( ω ), of OVA gels with C in the range of 30–59 wt% show angular frequency ω dependence characteristic of the critical gel with the fractal structure, i.e. G ′( ω ) ∼ G ″( ω ) ∼ ω ″ and tan δ = tan(nπ/2) over the whole ω range of 0.14–100 rad s −1 measured at three temperatures of 5.0, 25.0 and 45.0°C. This finding is confirmed by shear creep and creep recovery measurements as well as dynamic light scattering measurements on the same gels. The critical gel structure, however, is not formed either for gels with C C > 59 wt%.
- Published
- 1996