The traditional malting activity required innovative solutions to improve the quality of the malt produced. The objective of this study was to evaluate the effect of variation in steeping and germination conditions on the quality of sorghum (Sorghum bicolor (L) Moench) malt. Sorghum seeds were germinated under different times and temperatures after steeping in saline solution, tap, distilled and acidified water (pH 2.3). Malt quality was evaluated according to standardized methods after 24, 48, 72 and 96 hours of germination. The distilled water steeping has shown high germination rates at all evaluation periods compared to the other solutions. The protein contents have varied significatively according to the steeping and germination conditions between 129.37± 14.70 and 403.86 ± 8.47 mg/100 g while the carbohydrates content varied between 56.18 ± 9.81 and 223.92 ± 16.66 mg/100 g. The highest total protein content was obtained when steeping in distilled water for 24 h followed by germination for 72 h at 25 °C. The high content of carbohydrates was obtained by steeping with salt solution (0.9 %) for 12 h followed by germination for 24 h at 25 °C. The specific activity of amylase ranged from 8.39 ± 0.04 to 258.26 ± 3.23 U/mg protein while that of peroxidase ranged from 210.00 ± 6 to 3100.00 ± 25.00 U/mg protein. The optimum condition for obtaining maximum amylase activity was steeping in distilled water for 12 h followed by germination for 120 h at 25 °C. The optimum conditions for obtaining the peroxidase activities were steeping in salt solution of concentration (0.9 %) for 8 h followed by germination for 120 h at 45 °C. Germination under light increased amylase activity while germination in the dark was beneficial for the optimization of peroxidase activities. These results constituted a contribution for optimization of sorghum malting condition for improving alcoholic beverages and child-meal products quality.

Keywords: Sorghum malting, Sorghum steeping, Malting temperature, Sorghum malt nutrition, Malt quality optimization