Transfer of Fusarium mycotoxins from malt to boiled wort

Abstract

Malting was simulated using two different batches of barley as raw material: a naturally contaminated batch and laboratory inoculated (with a deoxynivalenol (DON) and zearalenone (ZEA) producing Fusarium graminearum strain) one. Up to three contamination levels were prepared, every process being carried out in triplicate. A significant washout effect on DON was observed by the end of the first water phase (between 22.4 and 34 % reduction) with an even more pronounced reduction (up to 75 % decrease) by the end of the steeping process. ZEA content remained almost unchanged (no significant difference between the initial and the final concentration). Germination was characterized by an increase in all the three toxins (ZEA, DON and DON-3-G) concentrations, however showing a decreasing trend in the last 24 h of the stage, compared to the first day of germination. Kilning lead to a significant reduction of DON in the naturally contaminated batch (46.6 and 78.8% decrease in level 1 and level 2 of contamination, respectively), nevertheless an increase in all other toxins and contamination levels was observed. Keywords: Deoxynivalenol, deoxynivalenol-3-glucoside, zearalenone, HPLC-DAD/FLD, malting.

The authors are grateful to the University of Lleida (grant JADE Plus 218/2016), and to the Spanish Ministry of Economy and Competitiveness (MINECO, Project AGL2014-55379-P and AGL2016-77610-R) for funding this work. Y. Rodriguez-Carrasco thanks the University of Valencia for his postdoctoral grant “Atracció de Talent”. The authors are grateful to Arthur Kendall for revising English proficiency.