The lowering of gushing potential from hydrophobin by the use of proteolytic enzymes

Abstract

Why was the work done: Gushing caused by hydrophobin originating from field fungal contamination of grain remains a significant problem in certain regions. We sought to explore whether the use of added proteinase enzymes could overcome the problem and allow the use of problematic grain. How was the work done: Four commercial proteinases were studied for their ability to digest hydrophobin and remove its foaming potential. One of those enzymes was then explored for its utility as an addition to mashing with a view to lowering the gushing potential of the ensuing beer. What are the main findings: The four enzyme preparations (Smizyme LP-G, Thermoase PC, Bromelain and Papain) were all capable of digesting hydrophobin. Of these, papain was chosen to assess whether the use of such an enzyme in mashing could ameliorate the gushing potential in finished beers. It was demonstrated that this can be achieved and without apparent detriment to the foaming potential of those beers. Why is the work important: It is now possible for brewers to consider an alternative approach to rectifying gushing risks if they are confronted with problematic grain. It must be stressed that this technique will not address the other main risk from infections of this type, namely the production of mycotoxins. Even in a context where gushing is not a problem, this work has indicated that there should be little concern with addition of papain at the mashing stage from a perspective of decreasing the foaming performance of beer.