Triticale malt (xTriticosecale Wittmack) a raw material for brewing - Using response surface methodology to optimise malting conditions

Response surface methodology was used to investigate the influence of three malting parameters, degree of steeping, germination time and temperature, on the quality of triticale malt. Each predictor variable was tested at three levels. Germination times were set to 5, 6, and 7 d, degrees of steeping to 42, 45, and 48 %, and germination temperatures were 15, 18 and 21 °C. The initial kilning temperature for all malts was set to 50 °C and gradually increased to 80 °C. A series of malt quality attributes were investigated including extract, viscosity, arabinoxylan, apparent attenuation limit, α- and β-amylase activity, limit dextrinase activity, α-amino nitrogen (FAN), Kolbach index, soluble N and dimethyl sulfide precursor (DMSP). The optimum malting programme was determined with 5 d germination time, 45 % degree of steeping, 15 °C steeping and germination temperature. The amylolytic and proteolytic activity obtained, were 84.8 % extract, 78.3 % AAL, 264 U/kg limit dextrinase activity, 1055 U/g β-amylase activity, 254 U/g α-amylase activity, 155 mg/L FAN, 1.7 mg/kg dimethyl sulfide precursor (DMS-P) and 2.305 mPa × s viscosity.