Investigations into the underlying mechanisms of primary gushing in beverages through micro dynamic modelling

• Applicant: Professor Dr.-Ing. Thomas Becker
• Subject Area: Biological Process Engineering
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 370878837

Gushing is the phenomenon of spontaneous uncontrollable foaming of non-agitated normally carbonized packaged drinks upon opening. When impacted by this phenomenon, producers not only experience financial loss due to repercussions of these faulty beverages, but also a tarnishing of reputation amongst consumers. Primary gushing is defined as gushing associated with the raw materials used and is of great scientific interest because the underlying mechanisms remain unclear.There has been a long established correlation within the malt based drinks industry between epidemics of primary gushing and cereal grown in unseasonably wet growing conditions. These wet growing conditions are well suited for the growth of particular Fusarium ssp. and it is hypothesized that hydrophobins produced by these Fusarium ssp., particularly HFBI and HFBII, are responsible for primary gushing. There remains, however, many uncertainties about the mechanism through which these hydrophobins would cause such a rapid expulsion of dissolved gas. A number of hypothesis have been postulated, including the stabilization of nano/micro bubbles by a hydrophobin monolayer thus creating nucleation points. However, the underlying mechanisms still require investigation.Through extensive experience related to the dynamic modelling of foams and bubbles in combination with the development of a bubble measurement cell, the applicant is in a unique position to gain a deeper understanding of the underlying mechanisms related to primary gushing. In the implemented bubble measurement cell, it is possible to inject individual bubbles under controlled conditions. With this measurement cell, the bubble development as a function of time can be recorded and analyzed using high speed cameras with microscopic lenses. These observations will be used in a Lattice Boltzmann method model to both validate the model and to explore through simulations the plausibility of the supposed mechanisms. These findings will be further verified through experimental observations using high speed cameras to observe the opening of malt based beverages which will be induced to gush through inoculation with HFBI and HFBII hydrophobins.

• DFG Programme: Research Grants