title: Proteomic analysis of differences in barley (Hordeum vulgare) malts with distinct filterability by DIGE.
abstract: Filterability is an essential quality parameter of barley malt and significantly impacts productive efficiency and quality of beer. In the study, differences of metabolic capability, rather than of initial contents of macromolecules in barleys, were found to be the main reason for malt filterability gap between the widely used cultivars Dan'er and Metcalfe in China. Comparative proteomics based on fluorescent difference gel electrophoresis (DIGE) was employed to quantitatively analyze proteins of four commercial malts belonging to the two cultivars, and 51 cultivar-differential spots were identified to 40 metabolic proteins by MALDI-TOF/TOF mass spectrometry, mainly including hydrolases and pathogen-related proteins. According to their function analysis and abundance comparison between cultivars, filterability-beneficial and -adverse proteins were putatively proposed. Two most remarkable differential proteins, β-amylase and serpin Z7, were further investigated to verify their effects on Dan'er malt filterability. These results provide biological markers for barley breeders and maltsters to improve malt filterability.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first report of comprehensive investigation of metabolic proteins related to wort filterability of barley malts, and sheds light on clues for filterability improvement. Visible differences in the expression level of metabolic proteins between Dan'er and Metcalfe malts using 2D-DIGE signify a valuable tool for cultivar comparison, illustration of key proteins responsible for filterability and even other qualities of barley malts. And with these explorations on biomarkers of malt filterability and other aspects, there will be higher efficiency and quality of beer brewing, less application of exogenous hydrolases and more expending market for Chinese malting barleys. This article is part of a Special Issue entitled: Translational Plant Proteomics.
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Jin
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Jun-Yong
authors.initials: JY
authors.lastname: Sun
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Mu
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
mesh_terms: D001515:Beer / Q000032:analysis; D005374:Filtration; D001467:Hordeum / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000032:analysis*; D040901:Proteomics; D015843:Serpins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D057825:Two-Dimensional Difference Gel Electrophoresis; D001614:beta-Amylase / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D015843:Serpins; D001614:beta-Amylase
keywords: Barley cultivars; Comparative proteomics; DIGE; Malt filterability; Mass spectrometry; Metabolic proteins