Wheat gluten proteolysis by enzyme preparations of directional action

Abstract A comparative study of enzymatic hydrolysis of dry wheat gluten was carried out by exo- protease and endoprotease enzyme praparations. Gluten of different rheological properties was conditionally divided into three groups on the basis of the compressive deformation index (Hdef) determined with the IDK-1 instrument: shortcleaved (Hdef 40 instr. units), good (Hdef 65 instr. units) and weak gluten (Hdef 80 instr. units). The optimal conditions for hydrolysis of different quality gluten by endoprotease enzyme praparations (Neutrase® 1.5MG, Protamex®) and exoprotease enzyme preparation (Flavourzyme® 500MG) were determined. The degree of proteolysis was assessed by the number of released amine nitrogen. It was shown that the stronger gluten is, the greater amount of amine nitrogen is formed under the influence of endoprotease (Neutrase® 1.5 MG, Protamex®), the weaker it is, the more nitrogen is formed under the influence of exoprotease (Flavourzyme® 500 MG). The most effective parameters of hydrolysis (time, concentration of the enzyme preparation, temperature, pH) revealed by us were specified by electrophoresis in polyacrylamide gel. The degree of hydrolysis necessary for achieving a certain molecular mass of peptides when used in breadmaking was determined. Thus, a process of hydrolysis of dry wheat gluten, aimed at expanding the range of its uses for improving and enriching wheat bread, was developed. We established that the functional properties of dry wheat gluten can be regulated by the change of the enzymatic hydrolysis time in the presence of the enzyme preparation Protamex®.