engleski

The effect of environmental conditions on barley hordeins

Barley malting quality has for many years been recognised as being highly dependent on the amount of grain protein. Hordeins, as the major barley endosperm protein fraction, represent an important determinant of end-use quality. Hordeins are found as a heterogenous mixture of polypeptides and have been categorized into three groups called the B, C and D hordeins. In the present study, we have analysed two sets of barley varieties, four spring and three winter, with aim to investigate the effects of environmental conditions on barley protein components and malt quality. The experiment was set up as multilocation trial during three years. Barley grains were analysed for total protein and hordein contents and micromalted. The hordein groups were characterized using reversed phase-high performance liquid chromatography (RP-HPLC). The total protein content of the barley grain was affected by different growing conditions. Marked variation in malt extract content over the different environments was observed. Hordein fraction content was also sensitive to the growing conditions, indicating that there was considerable variability between environments. Substantial differences in the distribution of protein among the B, C and D hordeins of the barley grain of these varieties were noted. Spring barley varieties had higher relative proportions of C and D hordein groups. In contrast, winter barley varieties showed higher relative proportion of B hordein group. Total hordein content significantly negatively correlated with malt extract content. Of the individual hordein groups, B hordein showed the strongest negative correlation with malt extract.

barley; hordeins; environment conditions; malt quality

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