Applicability of different brewhouse technologies and gluten-minimization treatments for the production of gluten-free (barley) malt beers: Pilot- to industrial-scale

The fate of gluten proteins and (poly)peptides throughout the brewing process of reference and gluten-minimized all-malt beers was monitored on both pilot-scale and industrial-scale. Common process steps such as wort separation, cooking, wort and beer clarification already significantly reduce the mass of gluten proteins (72-99%). Nevertheless, gluten derived (poly)peptides remained present at high concentrations in the final reference beers (58-397 ppm). A lauter tun, with course husk material as filter bed, showed to be more effective in reducing the mass of gluten proteins than a mash filter (33% vs. 18%). The mass of gluten proteins and (poly)peptides could be further significantly reduced (16-89% and 33-81% respectively) depending on the use of tannins, AN-PEP (Prolyl-endopeptidase from Aspergillus niger) and silica gel. To render all-barley malt beers gluten-free (≤20 ppm) (EC No. 41/2009, 2009) gluten-minimization treatments with AN-PEP and silica gel were combined successfully; these beers contained <5 ppm gluten proteins and <10 ppm gluten (poly)peptides.