However, further increase in xanthan concentration or
guar gum addition resulted in a decrease of the specific
volume compared to that of the control samples.
It seems that the effects of hydrocolloids on the structure
of the produced bread depend on specific hydrocolloid
concentration. Hydrocolloids such as xanthan can thicken
the crumb air cell walls (Rosell et al., 2001b) and its
increased concentration can enhance this phenomenon
leading to a more compact structure. Furthermore at higher
concentration, the stability effects of xanthan in the bread
can be reversed.