Method for continuously producing starch saccharification products by using high-concentration starch milk

A method for continuously producing starch saccharification products by using high-concentration starch milk, comprising the following steps:

• (1) a first pre-liquefaction step:
• adding medium-temperature alpha-amylase, high-temperature resistant alpha-amylase, lipase and neutral protease into starch milk having a pH of 5.0-6.0 and a dry basis mass fraction of 38 wt %-55 wt %, and preserving heat at a temperature of 45-60° C. for 0.5-1.5 hours to obtain a first starch milk;
• (2) a second pre-liquefaction step:
• adding starch into the first starch milk and stirring to obtain a second starch milk having a dry basis mass fraction of 50 wt %-70 wt %, adding medium-temperature alpha-amylase, high-temperature resistant alpha-amylase, lipase and neutral protease into the second starch milk, and preserving heat at a temperature of 50-60° C. for more than 0.5 hour to obtain a third starch milk;
• (3) a liquefaction step:
• performing spray liquefaction on the third starch milk, carrying out heat preservation for 3-5 min and then implementing flash evaporation, lowering the temperature of a product after flash evaporation to 97-99° C., and subsequently carrying out heat preservation for 2-3 hours at the temperature of 95-97° C. to obtain a starch liquefaction product;
• while performing spray liquefaction, supplementing starch, water and medium-temperature alpha-amylase, high-temperature resistant alpha-amylase, lipase and neutral protease into the third starch milk;
• and
• (4) a saccharification step:
• adjusting a pH of the starch liquefaction product to 4.0-4.5, lowering the temperature to 60-62° C., adding a composite saccharifying enzyme containing pullulanase and glucoamylase and removing transglucosidase, and carrying out heat preservation and saccharification for 36-40 hours at the temperature of 60-65° C. to produce starch saccharification products.