Beer proteomics analysis for beer quality control and malting barley breeding

A series of proteomic procedures has been applied to analyze beer and wort proteomes including two-dimensional gel electrophoresis combined with mass spectrometry (MS), pre-fractionation followed by gel electrophoresis and MS, and gel-free based shotgun liquid chromatography-MS/MS. These approaches have detected a number of protein species in beer and wort, from barley and yeast, and occasionally from rice and maize. Of these beer proteins, barley dimeric alpha-amylase inhibitor-1 (BDAI-1), barley trypsin inhibitor-CMe precursor (BTI-CMe) and yeast thioredoxin have been identified as factors responsible for beer quality traits of foam and haze. In addition, a number of hordein derived polypeptides involved to celiac disease have also been identified. Among these proteins and peptides, the modifications such as glycation and partial digestion in several proteins such as lipid transfer protein (LTP) and protein Z have been characterized. These findings may provide novel tools to improve quality control during beer processing and they may enhance selection in malting barley breeding.