Changes in catalase activities during malting of some improved Nigerian sorghum grain varieties

Abstract

The catalase activities of ten germinating improved sorghum varieties were monitored over a 4-day period to determine the effect of malting on them. This was done using standard methods that involved catalase assay at the appropriate experimental intervals. Results obtained showed that the different varieties of sorghum differed in their expression of catalase, a difference that was also reflected across the different stages of the malting process. The highest overall catalase activity (20.54 ± 0.74 U) was given by variety SK5912 after 72 hours of germination followed in second place by that from variety Nafelen (18.65 ± 0.99 U) obtained after steeping. The third and fourth highest value (17.88 ± 1.24 U and 17.08 ± 1.64 U) were given by KSV8 and Boboje after 72 and 48 hours of germination respectively. These values are probably indications that no single stage of malting was best for catalase expression among all the varieties. However, the fact that most of them (varieties ICSV 400, SK5912 and KSV 8, CSRO2 and ICSV III) all expressed their highest catalase activities after 72 hours of germination showed that 72 hours is probably the best germination stage for the elicitation of catalase among sorghum grains. The next best stage should be after 48 hours during which point three varieties (Boboje, NRL 3 and KAT 487) had their highest catalase activities. As a unity, all the sorghum varieties had their lowest catalase expression after 24 hours of germination, followed by those obtained after 96 hours germination.

Keywords: catalase, sorghum, malting, peroxidase, cereal enzymes