Structural and Enzymic Changes in Germinated Barley and Rye

Germination of barley and rye grains at 15°C and 56% moisture content resulted in the production of α-amylase, β-glucanase, endo-β-xylanase and α-arabinosidase. During germination of rye, enzyme activity increased significantly after the first day, whereas in the case of barley a rapid increase was not observed until after the third or fourth day. Rye varieties produced more xylanase, whereas barley produced more α-amylase and β-glucanase. Of the barley samples, germinated Pokko had the highest activities of β-glucanase, xylanase and α-amylase, and at 46% moisture content highest degradation of cell walls on the basis of image analysis. Arve had the highest α-arabinofuranosidase activity. Of the rye samples, Amando produced more xylanase and α-arabinosidase than Anna. The M_w of barley and rye β-glucan decreased significantly during germination. In rye samples, residual high molecular weight arabinoxylans were still present after 4 days of germination. The mass average molecular weight (M_w) of this fraction was 3 × 10⁶.