However, it can also be seen that when
a small amount of xanthan (0.1%w/w) was added to the starch suspension
of 3.9%w/w, a marked increase in viscosity was observed
across the studied shear rates and the mixture possessed a more pronounced shear thinning behaviour. This increase in viscosity
was extremely larger than the pure xanthan solution (0.22%w/w).
Similar to the steady shear experimental results, frequency sweep
experiment showed enhanced elastic property, i.e. higher storage
modulus, in the mixed system compared to the pure xanthan solution
(Fig. 6). Therefore, this investigation revealed that such viscosity
improvement of the mixed system was evidently from the
synergy rather than the additive effect. However, in this study,
we did not attempt to identify the mechanism of such synergy in
acidic condition, yet we simply showed that the use of modified
starch as a thickener or stabiliser in chili sauce product is of particular
commercial interest as it offers the possibility of novel functionalities
on the one hand and of using reduced levels of
xanthan gum, thus possibly reducing production cost, on the other.