Optimization of the application of commercial enzymes in sorghum mashes

Enzymes, Extracts, Other Session
Birgit Schnitzenbaumer, School of Food and Nutritional Sciences, National University of Ireland, University College Cork, College Road, Cork, Ireland
Co-author(s): Jean Titze and Elke Arendt, School of Food and Nutritional Sciences, National University of Ireland, University College Cork, Cork, Ireland

ABSTRACT: Brewing with unmalted sorghum involves the addition of exogenous enzymes such as alpha-amylase, beta-amylase, protease, and hemicellulase. High levels of commercial enzymes usually improve both extract content and processability of sorghum worts. However, a balance between product quality and production costs has to be established. The aim of this study was to optimize the application of commercial enzymes during mashing (infusion process) when replacing various levels of barley malt with unmalted sorghum. For this purpose, Nigerian white sorghum was fully characterized using standard methods specified by the Mitteleuropäische Brautechnische Analysenkommission, European Brewery Convention, or American Society of Brewing Chemists, as well as lab-on-a-chip capillary electrophoresis and scanning electron microscopy. The optimization of exogenous enzymes added to mashes containing up to 40% sorghum was achieved by monitoring rheological behavior during mashing using a Physica MCR rheometer. In addition, laboratory-scale mashing trials were carried out applying the optimized enzyme treatment for determining the quality of worts produced with various levels of sorghum adjunct. All analyses were done in triplicate. It has been revealed that the application of a Physica MCR rheometer for optimizing the addition of commercial enzymes to sorghum mashes is highly successful. The optimized use of exogenous enzymes in brewing has not only the ability to significantly improve the quality and processability of mashes and worts containing up to 40% unmalted sorghum, but also to significantly reduce the production costs of beer brewed with commercial enzymes.

Birgit Schnitzenbaumer successfully completed an apprenticeship as assistant tax consultant and worked in this job full-time before she studied brewing and beverage technology at the Technical University of Munich in Weihenstephan, Germany. During her studies, she completed several internships in breweries and did her master’s thesis on the effect of malting on the protein profile of proso millet (Panicum miliaceum L.) at the School of Food and Nutritional Sciences of the University College Cork, Ireland. Birgit graduated with a Dipl.-Ing. (M.S.) in brewing and beverage technology in 2009 and started her Ph.D. project on the application of novel and industrial enzymes when brewing with unmalted cereals at the University College Cork in November 2009.