The addition of starch is accompanied by changes in the surface
tensions from the original protein solutions (~45 & ~42 mN/m for
0.5 & 1wt.% EWP respectively.~47 & ~46 mN/m for 0.5 & 1wt.% PPI
respectively). There is a correlation between surface tension and
overrun for the EWP systems. Fig. 4a and 4c demonstrate dependency
of s on the OSA2 concentration (i.e. increase in OSA2
concentration yields a reduction in the surface tensions observed at
a given concentration of EWP). This is in accordance to the overrun
data observed in Fig. 3a and 3c, where a reduction of ~8 mN/m is
observed at 5wt% OSA2 and ~3 mN/m for 5wt% OSA1