The Black Gap: Understanding the Potential Roles of Black Fungal-Derived Enzymes in Malting and Brewing Quality: A Review

Abstract

The infestation of brewing grains with filamentous fungi can have wide-ranging effects, including poor processability during malting and brewing, diminished storage quality, and potential threats to food safety and human health. Darkly pigmented fungi, also known as dematiaceous fungi, that spoil cereal grains during ripening and storage comprise a rich source of extracellular enzymes, including various cellulolytic enzymes and other polysaccharide-degrading enzymes, along with proteolytic enzymes, that can modify the physicochemical properties of cereal grains, contribute to substrate hydrolysis during germination, and may have a negative influence on malting and brewing properties. This review article addresses the potential impact of dark-pigmented fungi on malting and brewing quality beyond food safety. It summarizes the current knowledge on secreted fungal hydrolytic enzymes involved in barley grain degradation and discusses their potential impact in terms of malting and brewing quality, focusing on dematiaceous fungi and those causing black symptomatology on the grain. Overall, this review highlights the necessity for further research into the impact of dark-pigmented fungi on malting and brewing quality.

Keywords:

• Barley
• enzymes
• fungi
• infected brewing cereals
• malting process

Author contributions

MB reviewed the literature and drafted the manuscript. BS, MG, and TB edited the manuscript. All authors have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

Disclosure statement

The authors report that there are no competing interests to declare.

Additional information

Funding

This work was supported by the IGF Project under Grant AiF 19766 N of the FEI, supported via AiF within the program for promoting the Industrial Collective Research (IGF) of the Federal Ministry of Economic Affairs and Climate Action (BMWK), based on a resolution of the German Parliament. This study was supported by the Forschungskreis der Ernährungsindustrie e.V. (FEI), Wissens­chaftsförderung der Deutschen Brauwirtschaft e.V. (WiFö), and Wissenschaftliche Station für Brauerei in München e.V. AiF Projekt;