THE GELATION OF DIALDEHYDE STARCH

The rheological behaviour of periodate oxidized potato starches has be en investigated in both dilute and concentrated aqueous dispersions. O n heating, low viscosity solutions were obtained at low concentrations and viscoelastic gels at high concentrations. During the gelation pro cess, two types of gel structure were distinguished. First a particle gel is formed, and on continued heating and shearing, deformation and disruption of the granules is observed, resulting in the formation of a polymer network. The increasing stability of the particle gels with increasing degree of oxidation has been attributed to an increase in p article rigidity. The aldehyde groups in dialdehyde starch are suppose d to reinforce the granular structures, as a result of intragranular h emiacetalization. The gel stability could be improved by adding native potato starch to the premix. (C) 1997 Elsevier Science Ltd.