Authors: Qian Li 1, Kevin P. Smith 2, and Zhao Jin 1
1. Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
2. Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN, USA
Corresponding author: Zhao Jin, zhao.jin@ndsu.edu
Presenting Author: Qian Li
Abstract
Fusarium infection in barley remains a persistent challenge for the brewing industry, primarily due to the pathogen’s ability to re-grow and proliferate during the malting process. This study investigated the multifaceted impacts of Fusarium infection on malt quality and the characteristics of soluble arabinoxylan (AX), including the content of ferulic acid bound to AX, since the oxidative crosslinking of ferulic acid within AX is associated with the resistance mechanisms of host plant against pathogen infection. Three barley varieties, AAC Synergy, Colon, and S2M184, cultivated in yield trials (Control) and Fusarium head blight (FHB) nurseries (Treatment) in St. Paul and Crookston, MN, were used as raw materials. The barley samples were processed into malt and subsequently into wort under standardized conditions. In the control samples, the deoxynivalenol (DON) content in both barley and malt were below 0.6 µg/g. However, in FHB-infected barley and malt, the DON content ranged from 1.7 to 17.5 µg/g.
The analysis of wort demonstrated that Fusarium infection led to a significant increase in the molecular weight of AX, with an average increase of 46.8%, and values ranging from 8.2% to 127.9%. Conversely, the content of bound monomeric ferulic acid showed a marked decrease, ranging from 13.2% to 50.6%, depending on the barley variety and cultivation plot. This reduction is likely associated with the oxidative crosslinking within AX post-infection, driven by the potential formation of ferulic acid dimers, which may have also contributed to the observed increase in the molecular weight of AX. Notably, the variations in AX molecular weight and bound ferulic acid content in wort correlated closely with their DON levels in barley. Further, Fusarium infection resulted in the marked reductions in β-glucan content (average reduction of 75.51%) and α-amylase activity (average decrease of 23.77%), alongside a significant increase in wort color. These findings underscore the complex biochemical consequences of Fusarium infection on brewing quality and highlight the necessity for effective management practices to control infection in barley production.
Acknowledgements
U.S. Department of Agriculture under Agreement No. 59-0206-9-064 (cooperative project with USWBSI).
American Malting Barley Association.
North Dakota Barley Council.
James Gillespie for analyzing DON and John Barr for analyzing the malt quality.