Fate of triazole fungicide residues during malting, mashing and boiling stages of beermaking

The fate and behaviour of five sterol biosynthesis-inhibiting (SBI) fungicides (cyproconazole, diniconazole, epoxiconazole, flutriafol, and tebuconazole) during different stages of beermaking (malting, mashing and boiling) on laboratory scale was assessed. A significant correlation (r > 0.93, P < 0.05) was observed between amounts removed after steeping and the octanol/water partition coefficient (as log K-ow) of the fungicides. Although in smaller proportion than steeping, germination and kilning were significant stages on the fungicide dissipation. The carryover after malting ranged from 30% to 40% of the initial residues on barley. After mashing, a substantial fraction was removed with the spent grains in all cases (36-49%) whereas a weak fall after boiling was observed for the fungicide residues (<= 2.5%). The calculated transfer factors (TFs) do not indicate a concentration effect after processing in any case (TFs < 1). Finally, after the storage of malt and spent grains (3 months) a slow fall in the residual content was observed. (C) 2010 Elsevier Ltd. All rights reserved.