Mutation analysis of barley malt protein Z4 and protein Z7 on beer foam stability

Takashi Iimure, Tatsuji Kimura, Shigeki Araki, Makoto Kihara, Masahide Sato, Shinji Yamada, Tatsuro Shigyou, Kazuhiro Sato

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Beer foam stability is an important characteristic. It has been suggested that isoforms of protein Z, that is, protein Z4 and protein Z7, contribute to beer foam stability. We investigated the relationship between beer foam stability and protein Z4 and protein Z7 using their deficient mutants. As a protein Z4-deficient mutant, cv. Pirkka was used. Protein Z7 deficiency was screened in 1564 barley accessions in the world collection of Okayama University, Japan. The barley samples from normal, protein Z4-deficient, protein Z7-deficient, and double-deficient were genotyped in F 2 populations and then pooled based on the DNA marker genotypes of protein Z4 and protein Z7. For a brewing trial, F 5 pooled subpopulations were used. After malting and brewing, the foam stability was determined, and the results showed that the levels of foam stability in the four samples were comparable. Two-dimensional gel electrophoresis was used to investigate the proteome in these beer samples. The results showed that low molecular weight proteins, including lipid transfer protein (LTP2), in the deficient mutants were higher than those in the normal sample. Our results suggest that the contribution of protein Z4 and protein Z7 to beer foam stability was not greater than that of other beer proteins.

Original languageEnglish
Pages (from-to)1548-1554
Number of pages7
JournalJournal of agricultural and food chemistry
Issue number6
Publication statusPublished - Feb 15 2012

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)


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