Prolamin Levels through Brewing and the Impact of Prolyl Endoproteinase

Abstract

Beer is derived from grist materials that contain gluten-type protein; therefore, it has long been assumed that it should not be consumed by those with celiac disease. However, because a significant objective of the malting and brewing process is protein precipitation and modification, beer may be rendered low in gluten from these processes alone. The levels of prolamin have been monitored throughout the brewing process with the RIDASCREEN Gliadin competitive R5 enzyme-linked immunosorbent assay method. The barley malt contained 6,832.3 ± 61 mg/kg, but only 131.1 ± 1 mg/kg of prolamin remained after fermentation. Addition of prolyl endoproteinase lowered the level of prolamin still further, to levels below the reliable limit of detection. A significant difference in foam stability was observed between the control and the prolyl endoproteinase-treated gluten-free beer, but no other beers were significantly affected by the addition of this enzyme.