A new method is presented to determine the phase diagram of mixed aqueous biopolymer systems using Fourier transform infrared spectroscopy coupled with partial least-squares analysis. We present the equilibrium phase diagrams of aqueous amylopectin/gelatin mixtures allowed to phase separate at a temperature outside the range within which either polymer could gel. The method is capable of detecting the changes in the phase diagram when the molecular weight of one of the components is altered. The phase diagrams are analyzed in terms of the Flory-Huggins theory for ternary systems. The method we have developed can be extended to any other combination of polymers in solution which show sufficient spectral difference.

No abstract

No abstract

Weak amylopectin gels have been formed directly following dissolution of waxy maize granules. Rheological characterisation of these gels has been carried out as a function of stress and frequency. The gels are visually clear and homogeneous, and environmental scanning electron microscopy shows no trace of the original granules remaining. It is postulated that the origin of the gel network lies in pairwise aggregation of outer chains of the amylopectin molecules, presumably via double helix formation. However, these pairs of chain segments do not aggregate to develop crystallinity.

No abstract