Method for producing wheat glutamine peptide

An industrial enzymatic hydrolysis method for producing glutamine peptide from wheat gluten powder, comprising the following steps:

• 1) mixing the wheat gluten powder with water with a liquid-feed ratio of 100:2-20 (L:kg) to form a slurry, adjusting the slurry to pH 8-12, heating to 50-90° C. and stirring at this temperature for 20-90 min, to form a basic liquid material,
• 2) separating the basic liquid material into supernatant and residue, collecting the residue and diluting the residue with water, heating to 50-80° C., stirring and separating, to obtain a purified residue, and
• 3) mixing the purified residue with water with a water-residue ratio of 100:10-50, stirring, adjusting to pH 7-9, heating to 40-60° C., and then adding subtilisin A from Bacillus licheniformis in an amount of 1000-8000 units per gram protein, reacting for 1-5 h to obtain a first enzymatic hydrolysate, after that, without removing or inactivating the subtilisin A in the first enzymatic hydrolysate, directly adding papain in an amount of 1000-2000 units per gram protein to the first enzymatic hydrolysate, and performing enzymatic hydrolysis under a temperature of 45-55° C. for 1-3 h, to obtain a second enzymatic hydrolysate, heating the second enzymatic hydrolysate to 120-135° C. to conduct enzyme inactivation, to obtain wheat protein enzymatic hydrolysate;
• wherein after step 3), the method further comprising:
• 4) centrifuging the wheat protein enzymatic hydrolysate with a tubular centrifuge, collecting centrifugal clear liquid, filtering the centrifugal clear liquid by a microfiltration equipment and an ultrafiltration equipment with a pore size of 0.05-0.1 μm under a pressure of 0.2-0.4 MPa and a temperature of 30-80° C. , to obtain a clear permeate liquid of wheat glutamine peptide,
• 5) evaporating the clear permeate liquid by a double-effect falling-film evaporator under vapor pressure of 0.1±0.02 MPa and a temperature of 40-80° C., until the solid content of the clear permeate liquid reaches to 20-50%;
• and then heating to 70-95° C., adding active carbon in the amount of 5-10% of the solid content, and stirring at this temperature for 20-40 min to perform decolorization, so as to obtain a concentrated liquid of wheat glutamine peptide,
• 6) drying, by a centrifugal spray drier, the concentrated liquid of wheat glutamine peptide under an inlet temperature of 160-180° C. and an outlet temperature of 80-90° C., to obtain wheat glutamine peptide powder.