Rheological Properties of Concentrated Pectin Gels Made through Diffusion of Alcohol at the Normal Room Temperature in the Concentrated Sub-Acid Pectin Solution

Abstract

Stress relaxation curves of pectin gels of 5.4-8.5% over the temperature range of about 9-25°C up to 2hr. have been obtained using a chainomatic balance relaxometer. Those curves were represented using a 6-elements mechanical model consisting of 3 Maxwell elements in parallel, and the following results are obtained.
1) The instantaneous elastic modulus, E0, and the elastic constant, E1, of the Maxwell element with the longest relaxation time, τ₁, are approximately proportional to C^1·7 and C^1·8, respectively, where C is (wt%) percentage of pectin.
2) An apparent activation energy obtained from the temperature dependence of τ₁ is a nearly constant value of about 7-8kcal/mol.
From the results described above, it may be said that the concentrated pectin gel which was experimented by this author has a constant three dimensional network structure independent of its concentration.