The better performance of OSA2 in terms of overrun within EWP
systems can be attributed to its hydrophobicity, it is readily cited
that qoptimum ¼ 60e70 for foams and above these cited values the
hydrophobicity of the particle can be detrimental to foam formation
and stabilization (Hunter et al., 2008). Table 3 shows the
contact angle of the three starches used within this study. The
desirable contact angle of OSA2, means that it has the potential to
compete with the proteins for the interface. Therefore OSA2 can
preferentially adsorb at the interface. This is in contrast to OSA1,
Fig. 3d where concentration has little effect on the foam overrun,
suggesting that the EWP is dominating at the A/W interface.