Process for preparing sour soybean milk starter by adopting soybean cake as raw material

The invention discloses a process for preparing a sour soybean milk starter by adopting soybean cake as a raw material. The process comprises the following steps: (1) raw material treatment; (2) enzymolysis; (3) centrifuging; (4) high pressure homogenization; (5) sterilization; (6) cooling; (7) grafting; (8) insulated fermentation; (9) demulsification; (10) centrifuging; (11) lyophilization; and (12) subpackage. According to the process, soybean cake is utilized to prepare a directed vat set starter product, on the one hand, soybean byproducts can be sufficiently utilized, and the utilizationrate of vegetable protein can be improved; and on the other hand, the development of starter industry can be promoted, and the cost for fermented diary beverage can be reduced. By adding a demulsifying agent, the effect of separating water and milk can be improved, the centrifuging intensity can be reduced, and the destruction of centrifuge on viable organisms can be reduced; the lyophilizing timeis shortened, the energy