engleski

Barley malt protein modification of selected winter and spring cultivars

Samples of the six malting barley cultivars were collected from two different locations, Osijek and Nova Gradiska, during the harvest years of 2004, 2005 and 2006. Zlatko, Barun and Vanessa are two-rowed winter type barley cultivars and Fran, Matej and Scarlett are spring barley cultivars. These samples were subjected to grain analyses, comprising protein content and hordein fraction content by reversed-phase high-performance liquid chromatography (RP-HPLC). The samples were micro-malted and the malts were analyzed to determine the influence of grain composition and the influence of growing conditions on malt extract and protein modification during malting. The results of grain protein content showed that there was no significant difference among cultivars of different seasonal type, but the protein component was highly sensitive to the growing conditions. The primary storage protein fraction in barley grain, hordein, was significantly affected by a growing season, but was less influenced by location. Marked variation in malt extract content over the different cultivars and environments was also observed. Malt protein modification indicators have included Kolbach Index (KI), free amino nitrogen (FAN) and the rate of hordein degradation during malting. Significant differences among cultivars and environments were found for all traits. The reported results clearly indicate that barley breeding trials are grown essentially to test the malting quality potential of selected cultivars.

barley cultivars; malt; growing conditions; protein modification

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