Method for preparing an ipp- and vpp-rich hydrolysate from wheat gluten protein by enzymatic hydrolysis

A method for preparing IPP- and VPP-rich hydrolysate from wheat gluten protein by enzymatic hydrolysis, comprising the following steps:

• (1) dissolving wheat gluten protein in an alkaline solution, and performing ultrasonic treatment to obtain a wheat gluten protein solution;
• the alkaline solution is a Na2CO3 solution with a pH of 9.0 to 13.0;
• the ultrasonic treatment condition is power of 50 to 100 W and treatment time of 5 to 25 min;
• (2) adding the alkaline protease to the wheat gluten protein solution to hydrolyze for 2 to 8 hours at 40˜60° C. to obtain an alkaline hydrolysate;
• the alkaline protease is Alcalase 2.4L or Bacillus licheniformis 2709 alkaline protease, with the addition amount of 0.1˜3.0% of the weight of wheat gluten protein in the reaction system;
• (3) adjusting the pH value of the alkaline hydrolysate to neutral or weakly acidic, and adding protease to hydrolyze, and hydrolyzing at 45˜75° C. for 2 to 6 hours, inactivating the enzyme at a high temperature to obtain a hydrolysate;
• the protease is a flavourzyme and a compound protease, or a flavourzyme and a papain, whose addition amount is 0.1˜3.0% of the weight of the wheat gluten protein in the reaction system;
• (4) inactivating the hydrolysate, centrifuging to take the supernatant, ultrafiltrating with an ultrafiltration membrane, and collecting a permeate;
• (5) decolorizing and debitterizing the permeate using a macroporous resin to obtain a debittered and decolorized liquid;
• (6) After the debittered and decolorized liquid is adsorbed by an ion exchange resin, eluting the ion exchange resin, to obtain an IPP- and VPP-rich hydrolysate;
• (7) drying the hydrolysate to obtain a powder of IPP- and VPP-rich hydrolysate.