| Abstract
| - Detailed studies were carried out on the influence of corn size distribution on the values obtained fordiastatic power (DP) of commercially malted barley. Malted barley was screened using a screeningbox, and the DP activities of the different corns retained on the different compartments of the screeningbox were determined. The malt samples retained on the 2.8 mm screen had the highest DP activity,whereas the small corns (≤2.2 mm) had the lowest levels of DP activity. When the DP results of thecorns retained on the different screens were weighed in relation to the percentages of grains retainedon each screen, the results obtained were very similar to those obtained from the mixed, unscreenedmalt samples. The results indicate that the higher the percentage of large corns in a malt sample,the higher the levels of DP found in the malts. In malt samples from both the Decanter and Maresivarieties/cultivars, regression analysis showed that large corns accounted for 87% of the variation inDP. These studies confirmed that corn size distribution is a very important factor in determining theDP level of malted barley. The study is of commercial significance because within a variety, with asimilar range of nitrogen, large corns produce malt of higher DP. When the percentage of large cornsis high, this should give extract with improved fermentability (yield of fermentable sugars). Thegelatinization properties of different grain size fractions, some of which were malted individually, werealso studied using a rapid visco analyzer (RVA), and this showed that kernel size had an importantimpact on the physical properties and malting performance. Keywords: Corn size distribution; diastatic power; malt quality; rapid visco analysis
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