Exceptional stability of food foams using class II hydrophobin HFBII

The foam stability of aerated solutions containing the Class II hydrophobin protein HFBII from Trichoderma reesei has been investigated and compared with that of other typical food emulsifiers and aerating agents. In simple solutions, we have found that 0.1 wt% HFBII forms exceptionally stable foams across a wide range of solution pH conditions. In aerated solutions comprising xanthan thickener, in order to slow the rate of creaming, we demonstrate that the foams stabilised by HFBII show no significant change in bubble size or air phase volume over a period of at least 4 months. Such foam stability is far in excess of any food-aerating agent of which we are currently aware. HFBII stabilises foams purely by adsorption to the air–water surface, forming a highly elastic surface and providing resistance to both coalescence and disproportionation, without influencing the aqueous phase viscosity.