FORMATION OF KINETICALLY TRAPPED GELS IN THE MALTODEXTRIN-GELATIN SYSTEM

摘要

A simple experimental procedure of cooling mixed maltodextrin-gelatin systems at various scan rates and to a range of final temperatures was employed to determine whether the state of thermodynamic equilibrium in solution is sustained in the structural organisation of the composite gels. Small-deformation dynamic oscillation and Visible spectrophotometry results demonstrate that the development of network rigidity and the polymeric weight ratio at which phase inversion occurs in the mixture is heavily governed by the applied thermal regime. There is an antagonistic effect operating between ordering-aggregation leading to gelation and the extent of phase separation, with rapid quenching and slow cooling (e.g., 1 degrees C/min) promoting the former and latter mechanism, respectively. Theoretical modelling indicates that either polymeric component holds disproportionate amounts of solvent in its phase when it forms the continuous matrix, It was concluded that, within the experimental time-temperature constraints, composite gels are kinetically trapped away from conditions of thermodynamic equilibrium observed for their mixtures in solution. (C) 1996 Elsevier Science Ltd. [References: 16]