Beta-amylase activity and thermostability in two mutants derived from the malting barley cv. triumph

The malting barley cuitivar, Triumph, and two mutants derived from it with higher (TLS) and lower (TL43) dormancy, respectively, were grown in replicated trials at Lieida, Spain and Dundee. Scotland, in 1999. Measurement of beta-amylase in the mature grain showed both mutants to have higher enzyme activity than the parental type with Spanish-grown samples higher in beta-amylase than Scottish-grown. There were no genotypic differences in beta-amylase thermostability or in the portion of the enzyme that was water-soluble. However, for all three genotypes, Scottish-grown samples had a higher proportion of water-soluble beta-amylase and total beta-amylase thermostability was also higher in the Scottish-grown sampler. Data from the Spanish-grown samples suggested that water-soluble beta-amylase was slightly more thermostable than the portion of the enzyme released by papain. (C) 2001 Academic Press.