46E-17 |
Malt and wort properties of Kenyan sorghum varieties germinated for different time periods |
J. MUORIA, UAF, 11452 W. 17th Place, Lakewood, CO 80215 and P. J. Bechtel, School of Fisheries and Ocean Sciences, University of Alaska, 245 O'Neil Building, Fairbanks, AK 99775. Sorghum is used in Africa and Asia to produce malt for making beer. However, there are limited studies on sorghum as a brewing cereal especially in Africa. The aim of this study was to evaluate and document the properties of malts and worts made from six varieties of sorghums grown in Kenya. Six Kenyan Sorghum varieties; Serena, Seredo, KAT 369, VO01, PGRC 101 and IS76 were germinated at 22 °C for 2, 4 and 6 days; dried at 55 °C for 18 hours and worts made. Wort filtration, pH, extract in ° Plato, hot water extract, Kolbach Index, viscosity, malt nitrogen, soluble nitrogen and wort turbidity, were determined. Means were compared (p<0.05) using a 6*3 Proc GLM SAS analysis. The grain protein contents were 9.44, 8.87, 12.22, 8.63, 9.46, 8.95 % DM for Serena, Seredo, KAT 369, V001, PGRC 101 and IS76, respectively (significantly different at p<0.05). Carbohydrate contents (64.00 - 70.14%) were significantly different (p<0.05). Extract in ° Plato and Kolbach Index increased with germination time at 22°C. The Kobach Indices for the sorghums were less than 33 % except for V001 at 6 days. Serena and Seredo had high viscosity levels (1.64 and 1.57) at 6 days, which were greater than the recommended levels of 1.45 cP. Seredo and Serena had a high turbidity levels while KAT 369 had a high protein value (1.807) at 6 days. High levels of viscosity and proteins coupled with low Kolbach index can result in beer with haze and filtration problems. This study suggests that sorghum should be germinated at higher temperature than 22 °C; however, better worts were made with four and six days of germination. Variety differences were apparent at the 22 degree C germination temperature and could be used in a grain breeding program.
Session 46E, International
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