MBAA TQ https://doi.org/10.1094/TQ-58-1-0111-01 | 
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Chukwudi I. Nnamchi, UdoChukwu P. Anyim, IfeChukwu A. Ekwu, and Chioma O. Amadi. Department of Microbiology, University of Nigeria, Nsukka, Nigeria
Abstract
Three improved Nigerian sorghum grain varieties were studied for the effects of steep period and regimen (air rest and continuous) on the development of amylolytic activity in grains periodically withdrawn (every 12 h for 72 h) and malted. A few preliminary grain and malt quality properties of the grains, which include root length, thousand kernel weight (TKW), germinative energy, germinative capacity, and water sensitivity, were first determined. The response of root lengths to steep time and regimen varied with the sorghum varieties, with the highest root length being observed for CSR 01 variety (4.38 cm) after 48 h of steeping with air rest. Values obtained for the other parameters were TKW, 30.10 ± 0.14, 37.05 ± 0.35, and 22.94 ± 0.38 g; germinative energies, 99.50 ± 0.71, 98.50 ± 2.12, and 94.00 ± 4.24 %; germinative capacities, 97.50 ± 2.12, 81.00 ± 4.24, and 86.50 ± 2.12; and water sensitivities, 1.00 ± 0.01, 2.50 ± 0.71, and 4.00 ± 0.03% for CSR 01, Samsorg 45, and Samsorg 40, respectively. Results obtained for the amylolytic activities of the sorghum varieties showed that Samsorg 40 gave the highest α-amylase value of 223.60 µg of glucose equivalents (GEs) after 48 h of continuous steeping, whereas the highest value for its air-rested counterpart was 219.22 µg of GEs obtained after 60 h of steeping. For β-amylase, Samsorg 40 again gave the highest value, 52.24 µg of GEs, for both the continuously steeped and air-rested types.
Keywords: amylase, brewing, cereals, diastatic power, malting, sorghum, steeping
