Comparison of fermentation results and quality of the agricultural distillates obtained by application of commercial amylolytic preparations and cereal malts

Abstract

The objective of this study was to determine the efficiency of rye starch hydrolysis in mashing processes using either enzymatic preparations or cereal malts and their effect on the chemical composition of prepared mashes, fermentation results, as well as the composition of the obtained distillates. The raw materials used were unmalted rye grain and different malts (wheat, rye, and barley malts). The differences in the chemical composition of the distillery mashes, depending on the type and amount of malts used, were observed. The concentrations of reducing sugars were twice as high in mashes containing 30 % cereal malts as in the reference sample prepared with enzymatic preparations (56.2 ± 1.8) g glucose L−1 mash. An increase in the content of cereal malt in mashes from 30 to 50 % did not significantly improve the initial degree of starch saccharification. The highest ethanol content (8.40 ± 0.25) % vol. was found in the mash containing 50 % rye malt, but the fermentation efficiency in this case was the lowest among all fermentation trials and reached only (75.39 ± 1.88) % of the theoretical value. The highest efficiency of process (87.92 ± 2.19) %, comparable to that obtained from the rye mash digested with amylolytic preparations (86.60 ± 2.17) %, was found in the mash prepared with 50 % wheat malt. The fermentation of mash containing 50 % unmalted rye grain and 50 % barley malt gave the lowest ethanol concentration (6.60 ± 0.12) % vol. in the mash after fermentation. The distillates originating from mashes containing cereal malts were characterized by lower concentrations of undesirable acetaldehyde than the distillate obtained from unmalted rye alone.