title: Changes in polyphenol compounds and barley laccase expression during the malting process.
abstract: BACKGROUND
  Polyphenols and phenolic acid are able to slow down or prevent oxidation processes and are therefore thought to have important effects in malting and brewing. Laccase catalyses the oxidation of a wide variety of substrates, including polyphenols. The aim of this paper was to determine the changes in polyphenol compounds and the relative expression of the HvLac1 gene during malting.
  
  
  RESULTS
  The dominant phenolic acid was ferulic acid. The amount of ferulic acid increased, whereas the amount of vanillic acid decreased during malting. The highest levels of expression of the HvLac1 gene were observed during the third air rest period in varieties with the 'Haruna Nijo' (HN) allele, as recommended for the production of beer with the protected geographical indication (PGI) 'Česke pivo' (Czech beer), whereas the highest expression was observed in the first day of germination in varieties with the 'Morex' (M) allele. However, the profiles of HvLac1 gene expression in varieties with alternative alleles during malting were similar, and the level of polyphenol compounds throughout malting was different.
  
  
  CONCLUSIONS
  The polyphenol contents in barley increased several-fold during malting, and the degree of increase differed with variety. The expression of HvLac1 transcript was similar in every barley variety.
authors: Crop Research Institute, Drnovská 507, 161 06 Praha 6, Ruzyně, Czech Republic.
authors: Lenka
authors: L
authors: Tomková-Drábková
authors: Research Institute of Brewing and Malting, PLC (RIBM), 12044 Praha, Czech Republic.
authors: Vratislav
authors: V
authors: Psota
authors: Research Institute of Brewing and Malting, PLC (RIBM), 12044 Praha, Czech Republic.
authors: Lenka
authors: L
authors: Sachambula
authors: Crop Research Institute, Drnovská 507, 161 06 Praha 6, Ruzyně, Czech Republic.
authors: Leona
authors: L
authors: Leišová-Svobodová
authors: Research Institute of Brewing and Malting, PLC (RIBM), 12044 Praha, Czech Republic.
authors: Alexandr
authors: A
authors: Mikyška
authors: Crop Research Institute, Drnovská 507, 161 06 Praha 6, Ruzyně, Czech Republic.
authors: Ladislav
authors: L
authors: Kučera
mesh_terms: D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D001467:Hordeum / Q000201:enzymology*; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D059808:Polyphenols / Q000737:chemistry*; D011422:Propionates; D036226:Seedlings / Q000201:enzymology*
chemical_list: D003373:Coumaric Acids; D059808:Polyphenols; D011422:Propionates; C004999:ferulic acid; D042845:Laccase; C495469:p-coumaric acid
keywords: barley; laccase; malting; polyphenols