Effect of Different Steeping and Malting Regimen on the Amylolytic Activities of Some Improved Nigerian Sorghum Grain Varieties

Abstract

Three Nigerian improved sorghum varieties were evaluated to ascertain how different steeping and malting regimen affect their amylolytic enzyme development. Steeping incorporated air rest and continuous steep regime for 72 h. Samples were withdrawn every 12 h. Germination was then carried out for four days before kilning at 50°C for 24 h. Grain and malt parameters were examined. Results obtained showed variations in the response of sorghum root length to steep regimen and time. CSR-02 gave maximum root length (3.32 cm) after 72 h of air rested steeping. CSR-02, Samsorg 44 and Samsorg 14 had germinative energies of 92.00 ± 4.24, 94.00 ± 1.41 and 96.00 ± 1.41%; germinative capacities of 91.00 ± 1.41, 75.50 ± 2.12 and 88.00 ± 2.83; water sensitivities of 6.50 ± 2.12, 13.50 ± 1.44 and 1.00 ± 0.41 respectively. TKW results were 29.73 ± 0.32, 33.85 ± 1.54 and 33.51 ± 0.41 kg for CSR-02, Samsorg 44 and Samsorg 14 respectively. Variations in the response of the sorghum varieties to various conditions of steep regime and steep period were also observed. Steeping for 48 h seems to be the optimum time for the development of amylolytic activity in all the sorghum varieties at both steeping regimens. Samsorg 14 gave the highest total amylase activity (355.44 µg glucose equivalents), followed by Samsorg 44 (278.08 µg glucose equivalents). Samsorg 14 also showed the highest α-amylase development (276.93 µg glucose equivalents). Air rest was found to be show greater effect on β-amylase development in all the sorghum varieties.