Protein Modifications and Metabolic Changes Taking Place during the Malting of Common Wheat (Triticum Aestivum L.)

Abstract

During the malting process, high molecular weight storage proteins are degraded by proteolytic enzymes to various degrees, from mid-size chains to amino acids. To date, very little is known about the biochemical pathways involved in the causation of this proteolysis and the secondary factors affected during malting of wheat. Changes in the contents and composition of protein fractions were investigated during the steeping, germination, and kilning processes. Pilot scale standard malting regimes were employed and frequent sampling ensured comparable analyses of proteolytic hydrolysis reactions. The wheat protein was fractionated and analyzed using Lab-on-a-Chip capillary electrophoresis and OFFGEL-capillary electrophoresis, thus providing a deeper insight into the proteolysis associated with wheat malting. The malt was analyzed according to applied malting and brewing methods. The primary finding of this research regarding wheat protein modification was that wheat proteolysis during malting is comparable to barley malt proteolysis. Both malts contain similar protein peaks in 2D capillary gel electrophoresis which, in barley malt, are known to have foam and haze stabilizing functions. Barley has been the focus of maltsters and brewers. Thus, wheat in malting and brewing has been somewhat overlooked from a scientific perspective.