FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Effect of malting time and fractionation of barley grain on malt Kolbach index and content of free amino nitrogen in worts


The objective of the investigations was to determine the effect of malting time and additional fractionation of brewing barley grain on the affluence of malt and worts produced thereof as regards the products of enzymatic hydrolisation of proteins. The investigation material were brewing barley grains of Lailla, Jersey, Hanka, and Brenda cultivars originating from the vegetation season in 2004, from the Lower Silesia region. All the grains analyzed were classified by their thickness into 3 fractions: standard grain fraction (grains larger than 2.5 mm), fraction of grains ranging from 2.5 to 2.8 mm, and fraction with grains larger than 2. 8 mm. The grains of the three fractions were then malted for 5, 6, and 7 days. In the laboratory worts obtained from these malts, the content of free amino nitrogen was determined, and the Kolbach index was calculated. The results obtained were analyzed using a Statistica software. Based on the statistical analysis performed, it was shown that neither the malting time of 5, 6, and 7 days nor the additional fractionation considerably impacted the value of Kolbach index. Those two factors did not considerably impact the content of free amino nitrogen in worts analyzed. The malts were characterized by a high loosening level. Thus, it seems justified to assume that when shortening the malting process period to less than 5 days, the economics of production could be improved owing to the shorter process duration and to the reduced natural malting losses related with the development of rootlets and acrospires. The additional grain fractionation affected neither the Kolbach index, nor the content of free amino nitrogen. Therefore, no technological justification exists of introducing the fractionation as an additional process when considering the product quantities of enzymatic hydrolisation of proteins.


Kolbach index, free amino nitrogen (FAN), malting, fractionation