Beer contains a variety of proteins and polypeptides, most of them originate from the proteolytic and chemical modifications of barley proteins occurring during brewing. In beer there are only a part of barley water soluble proteins, previously extracted, with molecular weights (MW) ranging from approximately 5 up to more than 100 kDa. However only two major proteins have been characterized, one of MW of 40 kDa, derived almost unmodified, from barley albumin protein Z and another with MW of about 10 kDa corresponding to lipid transfer protein 1 of barley (BLTP 1). In this study we analyzed the protein component modifications during brewing in order to evaluate the technological and healthy importance of beer protein fractions.