Dynamic rheological studies on mixtures of hot pepper-soybean paste and xanthan gum

Dynamic theological properties of hot pepper-soybean paste (HPSP) mixed with xanthan gum were evaluated at different gum concentrations (0.3, 0.6, and 0.9%) and fermentation times (12 and 24 week). Magnitudes of storage (G) and loss moduli (G") in the HPSP-xanthan gum mixture systems increased with an increase in frequency (omega)), while complex viscosity (eta*) decreased. G' values were higher than the G" values over most of the frequency range (0.63-63 rad/sec), and were frequency-dependent. The dynamic moduli (G', G", and eta*) of the HPSP-xathan mixtures were lower than those of the control (0% gum). The differences between the dynamic moduli values at 12-week and 24-week fermentation decreased with increasing gum concentration, showing that xanthan gum can be used to stabilize and improve the viscoelastic theological properties of HPSP. The G' value of the HPSP-xathan mixtures increased with an increase in gum concentration from 0.3 to 0.9%, whereas the G" decreased. The ability of xanthan gum to increase the elastic properties in the HPSP-xanthan mixture systems seemed to be the result of the incompatibility phenomena existing between xanthan gum and glutinous rice starch.