Combined Modeling and Biophysical Characterisation of CO2 Interaction with Class II Hydrophobins: New Insight into the Mechanism Underpinning Primary Gushing

Although there is a common agreement that hydrophobins and CO2 are responsible for primary gushing of carbonated beverages, the bio-molecular mechanism of this phenomenon is not well understood. Here, hydrophobin HFBII has been produced, extracted, and purified. A gushing test and DLS analysis was performed and allowed the authors to design an MD simulation setup to investigate the interaction of CO2 molecules with HFBII in time. The results indicate that CO2 molecules tend to aggregate at the hydrophobic patch of HFBII twice as much as to the rest of the protein. A model is proposed that elucidates the "nanobomb" formation depicting a definite chemical and biophysical description of the primary gushing mechanism. © 2012 American Society of Brewing Chemists, Inc.