Investigation of overfoaming activities and gushing mechanisms of individual beer ingredients as model substances in bottled carbonated water

BACKGROUND: Researchers in several disciplines are interested in understanding the spontaneous and eruptive overfoaming (gushing) of carbonated beverages, as it is an essential problem of both the brewing and beverage industries. In order to understand the mechanism(s) taking place in gushing beer, several beer ingredients have been investigated as model substances in a much simpler matrix of carbonated water. For this purpose, sinapic acid, vanillic acid, ferulic acid, cinnamic acid and palmitic acid have been chosen as model beer ingredients. RESULTS: Gushing formation of the investigated beer ingredients depends on the degree of stabilized solvated molecular carbon dioxide in water. For this purpose, functional groups capable of forming hydrogen bonds with electronegative oxygen atoms of carbon dioxide are needed. However, the solubility of the substances plays an important role in the abundance of these functional groups in undissociated form to interact with molecular carbon dioxide. CONCLUSION: The reported data provide valuable insights into the gushing problem and help to understand its formation pathways. Each gushing-positive substance has an individual mechanism related to its structural conformation and solubility level. Therefore possible gushing mechanisms have been proposed with respect to the structural changes in model substances to clarify the differences in observed overfoaming and gushing stability levels.