Investigation of protein composition of barley by gel electrophoresis and MALDI mass spectrometry with regard to the malting and brewing process

Abstract

The protein composition of barley partly determines its quality in terms of malting and brewing. For this reason, the water-soluble proteins of two different barley cultivars were investigated by gel electrophoresis and matrix-assisted laser desorp-tion/ionization mass spectrometry. Mass spectra were obtained directly from barley extracts by using three matrices. According to the quality of the measured spectra, it was possible to establish which matrix was the most suitable for the analysis of water-soluble proteins from barley. We found that the protein patterns did not differ significantly between Jersey and Tolar varieties. However, our results showed the influence of the malting process on the posttranslational modification of some water-soluble barley proteins. These proteins also survive the brewing process and they are very important for the formation and stability of beer foam. Several barley proteins were also identified by proteomic analysis. © 2008 The Institute of Brewing & Distilling.