Nigerian improved sorghum cultivars 'L538', 'YG5760', 'L1499', 'SSH1' and 'SSH3' were investigated for the effect of steeping conditions on their amylolytic development. The grains were steeped using 3 steep regimes SR 1, SR 2 and SR 3 which involved steeping and re-steeping in cold distilled and de-ionized water for 36, 45 and 54 h respectively. Grains in each SR were divided into 4 portions and further steeped for 6 h using final warm steep temperatures (FWST) of 30, 35, 40 and 45°C. α-and β-Amylase as well as diastatic activity were determined at different FWST. SR and FWST were correlated with enzyme development. Steeping conditions significantly (p<0.05) affected amylolytic development of the sorghum malts. Optimum moisture content (48%) was obtained at FWST of 35°C. α-Amylase was the predominant enzyme. All enzyme activities were at a peak at FWST of 30 and 35°C and at SR 2. The highest enzyme activity was recorded by cultivar 'YG5760' malt-(α-amylase 272, β-Amylase 169 μg equivalent glucose). High relationship existed between α-amylase and moderate relationship between β-Amylase and SR. Similar relationship existed between enzyme development and FWST.
Keywords: Diastatic activity; Sorghum cultivars; α-Amylase activity; β-Amylase activity.