Enzymolysis method of starchy material and preparation method of citric acid

Abstract

The invention relates to an enzymolysis method of a starchy material. The method comprises the steps of: (1) mixing a starch slurry obtained from a starchy material with part of enzymes so as to obtain a mixture, contacting the mixture with steam so as to make the temperature of the steam contacted mixture ranging from 75 to 95DEG C, under which the mixture is maintained for 30-90min; (2) contacting the steam contacted mixture in step (1) with steam again so as to make the temperature of the steam re-contacted mixture ranging from 100-120DEG C, under which the mixture is maintained for 1-10min; (3) cooling the steam re-contacted mixture to a temperature of 80-90DEG C, and mixing the cooled mixture with the residual enzymes for enzymolysis. The invention also provides a preparation method of citric acid. The methods provided in the invention provides a solution to the problem of high content of residual starch in an enzymolysis product (liquefied fluid), and can effectively enhance citric acid yield and reduce grain consumption, thus lowering the production cost of citric acid.

Description

technical field

[0001] The invention relates to an enzymatic hydrolysis method of starchy raw materials and a preparation method of citric acid. Background technique

[0002] Citric acid is an organic acid widely used in industries such as beverage, food and medicine. my country is a major producer of citric acid, with more than 20 production plants in the country, with an annual output of more than 800,000 tons. At present, citric acid is mainly prepared by fermentation. For example, it is generally necessary to pulverize the starchy raw material first, mix the pulverized product with water to obtain a starch slurry, and mix the starch slurry with an enzyme for enzymolysis to obtain an enzymatic hydrolysis product (liquefied liquid ), and Aspergillus niger was inoculated into the fermentation broth containing the enzymatic hydrolysis product and fermented to produce citric acid. However, the residual starch content in the enzymolyzed product obtained by the existing proce...

Images