The invention discloses a preparation process of maltooligosaccharide syrup with high maltotetraose content. The preparation process comprises the following steps of adding water into
starch to prepare
starch slurry, and adjusting the pH value of the
starch slurry to 5.8-6.0; adding high-temperature-resistant alpha-
amylase into the starch
slurry, and performing primary spray
liquefaction, laminar flow tank heat preservation and secondary spray
liquefaction to obtain liquefied liquid; when the liquefied liquid is rapidly cooled to 55-65 DEG C, adding
pullulanase and maltotetraose
enzyme sequentially for a saccharification reaction, and after the saccharification reaction is conducted for 5-18 h, obtaining reaction liquid; and enabling the reaction liquid to be subjected to
activated carbon decoloration,
ion exchange and concentration, and obtaining the maltooligosaccharide syrup. After
liquefaction is finished, the temperature is rapidly reduced to the saccharification temperature by adopting a flash
heat exchanger, the problems of starch aging and
retrogradation in the cooling process are avoided, saccharification is performed by adopting a two-step
enzyme adding method of firstly adding
pullulanase and then adding maltotetraose
enzyme, the conversion rate of maltotetraose is increased, the technological process is simplified, and the maltooligosaccharide syrup with maltotetraose content of more than or equal to 65% is prepared.