The Variation of β-amylase activity and protein fractions in barley grains as affected by genotypes and post-anthesis temperatures

Abstract

The variation of β-amylase activity and protein fractions in barley grains was evaluated using 148 barley genotypes grown in the field and two cultivars under in vitro culture with two temperature treatments during grain development. The results showed that there was significant genotypic variation in β-amylase activity and protein fraction content. Regression analysis indicated that β-amylase activity was positively correlated with total protein and the level of each of the protein fractions, with the correlation coefficient between β-amylase activity and hordein content being the highest. Furthermore, higher post-anthesis temperatures (32/26°C, day/night) significantly enhanced β-amylase activity and protein fraction content, presumably as a result of reduced starch content. Albumin and glutelin were the least and most affected, respectively, in comparison with the plants under lower temperature (22/16°C). Temperature post-anthesis also influenced the morphology of the starch A granule and the number of B granules, suggesting the altered starch structure may also be a reason for deteriorated malting quality under high temperatures. © 2009 The Institute of Brewing & Distilling.