use of response surface methodology to optimise malting conditions of proso millet (Panicum miliaceum L.) as a raw material for gluten-free-foods

• Published in: Journal of the Institute of Brewing 2007, Vol.113 (3), p.280-292
• Main Authors: Zarnkow, M, Kessler, M, Burberg, F, Back, W, Arendt, E.K, Kreisz, S
• Format: Article
• Language: English
• Subjects: alpha-amylase; amino nitrogen; Beers; beta-amylase; Biological and medical sciences; Cereal and baking product industries; color; enzyme activity; Fermented food industries; Food industries; Fundamental and applied biological sciences. Psychology; gelatinization; gelling properties; imbibition; Kolbach index; limit dextrinase; malt extract; malting; malting quality; millets; optimization; Panicum miliaceum; response surface methodology; seed germination; temperature; viscosity
• ISSN: 0046-9750; 2050-0416
• DOI: 10.1002/j.2050-0416.2007.tb00288.x

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.