Malting of Fusarium Head Blight-Infected Rye (Secale cereale): Growth of Fusarium graminearum, Trichothecene Production, and the Impact on Malt Quality.

Zhao Jin,Steve Zwinger,James Gillespie,Robert Brueggeman,Thomas Gross,Jaime Cumming,John Barr,Richard Horsley,Jochum Wiersma,Mark Sorrells,Paul Schwarz,Gary Bergstrom

doi:10.3390/toxins10090369

Zhao Jin, Steve Zwinger + Show 10 more

Open Access

https://doi.org/10.3390/toxins10090369

Copy DOI

Abstract

This project was initiated with the goal of investigating the malt quality of winter rye cultivars and hybrids grown in the United States in 2014 and 2015, but high levels of deoxynivalenol (DON) were subsequently found in many of the malt samples. DON levels in 75% of the investigated rye samples (n = 117) were actually below 1.0 mg/kg, as quantified by a gas chromatography combined with electron capture detector (GC-ECD). However, 83% of the samples had DON in excess of 1.0 mg/kg following malting, and the average DON level in malted rye was 10.6 mg/kg. In addition, relatively high levels of 3-acetate DON (3-ADON), 15-acetate DON (15-ADON), nivalenol (NIV), and DON-3-glucoside (D3G) were observed in some rye malts. Our results show that rye grain DON is likely a poor predicator of type B trichothecenes in malt in practice, because high levels of malt DON, 15-ADONm and D3G were produced, even when the rye samples with DON levels below 0.50 mg/kg were processed. Fusarium Tri5 DNA content in rye was highly associated with malt DON levels (r = 0.83) in a small subset of samples (n = 55). The impact of Fusarium infection on malt quality was demonstrated by the significant correlations between malt DON levels and wort viscosity, β-glucan content, wort color, wort p-coumaric acid content, and total phenolic content. Additional correlations of rye Fusarium Tri5 DNA contents with malt diastatic power (DP), wort free amino nitrogen (FAN) content, and arabinoxylan content were observed.

Highlights

Trichothecene mycotoxins, such as deoxynivalenol (DON), on brewing grains pose a food safety concern to maltsters and brewers, and several studies have shown that between 70 and >100% of the DON present on barley malt can be recovered in the finished beer [1,2,3]
The results suggest that rye DON is likely a poor predicator of malt trichothecenes in practice, because dramatically high levels of malt DON, 15-acetate DON (15-ADON), 3-acetate DON (3-ADON), NIV and D3G were produced even when the rye samples had DON levels of below 0.50 mg/kg
The current study demonstrated a very strong potential for the growth of F. graminearum and the formation of DON and other type B trichothecenes during the malting of Fusarium head blight (FHB) infected rye

Summary

Introduction

Trichothecene mycotoxins, such as deoxynivalenol (DON), on brewing grains pose a food safety concern to maltsters and brewers, and several studies have shown that between 70 and >100% of the DON present on barley malt can be recovered in the finished beer [1,2,3]. The results of the above surveys illustrate several important factors. A beer testing at 20 μg/L DON would translate to ≤0.10 mg/kg on the original malt, which is below the limit of quantification (LOQ) of many tests utilized in the grain trade.

Objectives

Methods

Results

Conclusion