The Use of Response Surface Methodology to Optimise Malting Conditions of Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten-Free Foods
Martin Zarnkow1,3,4, Matthias Keßler2, Felix Burberg1, Werner Back1, Elke K. Arendt3, and Stefan Kreisz1
1 Lehrstuhl für Technologie der Brauerei I, Technische Universität München Weihenstephan, Weihenstephaner Steig 20, 85354 Freising, Germany.
2 Saatenunion GmbH, Eisenstraße 12, 30916 Isernhagen, Germany.
3 Department of Food and Nutritional Sciences, National University of Ireland, University College Cork, College Road, Cork, Ireland.
4 Corresponding author. E-mail: Martin.Zarnkow@wzw.tum.de
J. Inst. Brew. 113(3), 280–292, 2007 | VIEW ARTICLE
ABSTRACT
Response surface methodology was used to investigate the influence of the three malting parameters, i.e. degree of steeping, germination time, and temperature on the quality of proso millet malt. Each predictor variable was tested at three levels. Germination times varied from 5, 6, and 7 days, degrees of steeping were 44, 48, and 52%, and germination temperatures were 16, 20, and 24°C. A set kilning temperature of 65°C was used for all malts. A series of malt quality parameters were investigated including extract, apparent attenuation limit, gelatinisation temperature, α-amylase activity, β-amylase activity, limit dextrinase activity, Kolbach index, α-amino nitrogen, viscosity, and colour. The optimal malting program was achieved after the fifth day of germination, 44% degree of steeping, and a 22°C steeping and germination temperature. The obtained values for the amylolytic and cytolytic attributes were 64.8% extract, 1.383 mPa × s viscosity, 76.0% apparent attenuation limit, 111 U/g α--amylase activity, and 102 U/g β--amylase activity.
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Publication no. G-2007-1126-501 ©2007 The Institute & Guild of Brewing