Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment
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Date
Authors
Kruger, Johanita
Oelofse, Andre
Taylor, Janet
Taylor, J.R.N. (John Reginald Nuttall)
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley-Blackwell
Abstract
Brewing and bioethanol production with raw grain and exogenous enzymes produces wort with satisfactory hot water extract (HWE). However, the free amino nitrogen (FAN) and mineral content can be too low, owing to low protein digestibility (PD) and phytate–mineral chelation, respectively. This study evaluated the potential for improvement in yeast nutrition in raw whole sorghum and maize brewing and bioethanol production by genetic modification (GM) of sorghum to improve PD and reduce phytate content, and by treatment with exogenous phytase. While phytase addition decreased sorghum spent grain phytate content (88%) and content of minerals (17 to 59%; i.e. increased wort mineral content), it did not affect maize phytate spent grain mineral content or HWE significantly. However, phytase addition did increase maize wort FAN (20%), sorghum HWE (2.8 percentage points) and wort FAN (23%). GM sorghum gave reduced spent grain mineral contents (11–38%), increased HWE (5.5 percentage points) and wort FAN (71%). Hence, genetic modification of sorghum to improve PD and reduce phytate content has considerable potential in raw grain brewing and bioethanol production to improve yeast nutrition.
Description
Keywords
Bioethanol, Genetic modification, Maize, Minerals, Phytase, Protein digestibility
Sustainable Development Goals
Citation
Kruger, J, Oelofse, A, Taylor, J & Taylor JRN 2012, 'Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment', Journal of The Institute of Brewing, vol. 118, no. 1, pp. 70-75.