Kvasny Prum. 2011; 57(7-8): 182-189 | DOI: 10.18832/kp2011016

Polyphenol compounds and antioxidative properties of barley varieties recommended for Czech beer.Peer-reviewed article

Alexandr MIKYŠKA, Ivo HARTMAN, Danuša HAŠKOVÁ
Výzkumný ústav pivovarský a sladařský, a. s., Praha, Lípová 15, 120 44 Praha 2

Polyphenol compounds in malt affect the antioxidative activity, sensorial and colloidal stability of beer. Polyphenol antioxidants play an important role in the sensorial aging of beer and also in the beneficial effects of beer drinking. Barley is a primary source of water-soluble polyphenol antioxidants and other reducing compounds, which are released and/or formed during malting. A set of six barley varieties recommended for the production of Czech beer collected from four localities (experimental stations) was used to study the content of polyphenol compounds and antioxidative capacity of laboratory malts prepared by a standardized process. In laboratory worts, we determined the content of polyphenol compounds, reductive capacity by the procedure using 2,6-dichlorophenolindophenol (RC-DCPI) and antiradical activity by using the radical 1,1-diphenyl-2-picrylhydrazyl (ESR-DPPH). The results revealed varietal differences and a significant effect of soil and climatic conditions on the parameters under study. The highest values of total polyphenols, flavanoids and a relatively low content of anthocyanogens (the highest polymeration index), as well as the highest values of ESR-DPPH and RC-DCPI, were found in the variety Aksamit. The varieties Blaník, Bojos and Advent were comparable in terms of the content of polyphenol compounds and reducing properties. The older variety Tolar exhibited a relatively low content of total polyphenols and low ESR-DPPH values but a high value of RC-DCPI. The lowest content and the least convenient composition of polyphenol compounds, as well as the lowest values of ESR-DPPH a RC-DCPI were determined in the variety Radegast. The antiradical potential ESR-DPPH-ARP showed the strongest correlation with the content of total polyphenols, RC-DCPI correlated most closely with the content of flavanoids in the wort. The content and composition of polyphenolics in the wort were locality-dependent. The highest content of anthocyanogens was determined in malts from the locality Krásné Údolí, the lowest in the locality Stupice.Polyphenol compounds in malt affect the antioxidative activity, sensorial and colloidal stability of beer. Polyphenol antioxidants play an important role in the sensorial aging of beer and also in the beneficial effects of beer drinking. Barley is a primary source of water-soluble polyphenol antioxidants and other reducing compounds, which are released and/or formed during malting. A set of six barley varieties recommended for the production of Czech beer collected from four localities (experimental stations) was used to study the content of polyphenol compounds and antioxidative capacity of laboratory malts prepared by a standardized process. In laboratory worts, we determined the content of polyphenol compounds, reductive capacity by the procedure using 2,6-dichlorophenolindophenol (RC-DCPI) and antiradical activity by using the radical 1,1-diphenyl-2-picrylhydrazyl (ESR-DPPH). The results revealed varietal differences and a significant effect of soil and climatic conditions on the parameters under study. The highest values of total polyphenols, flavanoids and a relatively low content of anthocyanogens (the highest polymeration index), as well as the highest values of ESR-DPPH and RC-DCPI, were found in the variety Aksamit. The varieties Blaník, Bojos and Advent were comparable in terms of the content of polyphenol compounds and reducing properties. The older variety Tolar exhibited a relatively low content of total polyphenols and low ESR-DPPH values but a high value of RC-DCPI. The lowest content and the least convenient composition of polyphenol compounds, as well as the lowest values of ESR-DPPH a RC-DCPI were determined in the variety Radegast. The antiradical potential ESR-DPPH-ARP showed the strongest correlation with the content of total polyphenols, RC-DCPI correlated most closely with the content of flavanoids in the wort. The content and composition of polyphenolics in the wort were locality-dependent. The highest content of anthocyanogens was determined in malts from the locality Krásné Údolí, the lowest in the locality Stupice.

Keywords: antioxidants, antiradical activity, barley variety, polyphenols, malt

Received: May 2, 2011; Accepted: June 2, 2011; Published: July 1, 2011 

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