Production of deoxynivalenol (DON) and DON-3-glucoside during the malting of Fusarium infected hard red spring wheat

Abstract

Wheat is increasingly utilized in malting and beer brewing, but there is little information on the behavior of Deoxynivalenol (DON) and DON-3-glucoside (DON-3-G) during the malting of Fusarium infected wheat. In this study, twenty Hard Red Spring wheat samples (DON levels of 0–10.13 μg/g) were micro-malted following 2- and 6- months of storage. DON was determined by GC-MS, DON-3-G by LC-MS and Fusarium Tri5 DNA by real-time PCR. When initially malted, DON levels increased by an average of 460% over that detected in 15 wheat samples which had original DON levels above the quantification limit (0.20 μg/g). DON levels in all the 15 malts exceeded of the FDA adversary limit of 1.00 μg/g. DON-3-G/DON ratios increased from 23 to 64 mol% following malting. The increase of DON and DON-3-G was attributed to the Fusarium growth in malting, with Tri5 DNA increasing by an average of 7.6- fold. The viability of Fusarium decreased in the later malting, but DON levels fell below 1.00 μg/g for only two malts. Levels of DON-3-G in the malts did not change significantly between the two malting dates.