Method for recovering coin protein sugar dregs and preparing protein nitrogen sources and nitrogen-containing syrup

The invention discloses a method for recovering coin protein sugar dregs and preparing protein nitrogen sources and nitrogen-containing syrup in the production of enzymatic corn starch sugar, comprising the steps of size mixing, liquefying, saccharifying, standing separation, centrifugal separation, proteolysis, concentration, drying, compounding, and the like. In the invention, protein is condensed under the heat flash of liquefying, the protein sugar dregs concentrate and float upwards in saccharifying, the sugar dregs are recovered through the steps of standing separation and centrifugal separation, the sugar dregs are dried into protein, or the sugar dregs are hydrolyzed to prepare protein nitrogen sources, and the nitrogen sources can be compounded with syrup to form nitrogen-containing starch syrup for fermenting. Clarified saccharification liquid after centrifugal separation is decolored, filtered, refined and concentrated, and starch syrup products are obtained. The majority of lentous sugar dregs in the saccharification liquid are removed before the treatment of decoloring and filtering, and the decoloring and filtering performance of the material is better. The use level of active carbon, and the like can be properly reduced, the production capability of filtering equipment is improved, and the frequency of the loading and unloading of filters as well as the consumption of washing waste water and various kinds of loss are greatly reduced.