The Effect of Kernel Size and Texture on the Malting Properties of Sorghum

Abstract

The effect of kernel size and texture of kernels on the malting properties of sorghum was investigated. Twelve sorghum cultivars were used for the study. The physical features of the kernels that were determined included the endosperm texture, endosperm type and kernel size. Also determined were the germination energy and germination capacity. To monitor the malting properties, the malting loss, hot water extract, cold-water extract and diastatic power were determined. The effect of duration of germination on the root and shoot lengths of kernels was also investigated. Two of the cultivars were floury while the other cultivars were corneous. All the cultivars were non-waxy. The mean percentage values of the germination energy and germination capacity were 84.92% and 91.75% respectively. As the germination period increased, root and shoot lengths of all the twelve cultivars also increased. The greatest change in the root and shoot lengths was observed between the second and third day of the germination period. The malting loss increased with the germination period and ranged between 15.5-33.0%. The malting loss for all cultivars reached its peak between the second and third day of germination. Malting loss was least for floury endosperm. The diastatic activity increased throughout the duration of germination. The diastatic activity was positively correlated with the cold water extract (r = 0.99) and hot water extract (r = 0.29). The cold water extract increased as the diastatic activity increased. The corneous grains were relatively high in diastatic activity but no correlation was obtained between the size indices and malting properties of the cultivars.



Keywords: Sorghum, Kernel size, texture, malting properties


J Food Tech in Africa (2002) 7, 78-81