Abstract: In order to investigate gel properties of cross-linked tapioca starch, the pasting and rheological properties of tapioca starch with different cross-linking degrees were determined using a rapid viscosity analyzer (RVA) and a dynamic rheometer. Viscosity measurement showed that final viscosity and setback first increased and then decreased with increasing cross-linking degree, while breakdown continuously decreased. The steady-state rheological properties showed that all tapioca starch pastes with different cross-linking degrees were pseudo-plastic non-Newtonian fluids (T0 > 0, n < 1). The dynamic rheological properties demonstrated that the storage modulus (G’) and loss modulus (G”) of the cross-linked tapioca starch gel (6% m/m) were improved throughout the whole frequency range (0.1～10.0 Hz) compared to the raw starch gel. The G’ of the properly cross-linked tapioca starch gel was increased, while tanδ was decreased during 2 h aging at 4 ℃. Compared to the raw starch gel, the G’ and G” of the cross-linked tapioca starch gel (15% m/m) were improved during both heating and cooling. During cooling, the G’ was increased rapidly with increasing cross-linking degree suggesting improved gel properties.

Key words: cross-linked tapioca starch, pasting properties, rheological properties, gel