The invention discloses a preparation method of soybean
dietary fiber. The preparation method of the soybean
dietary fiber comprises the following steps: 1) carrying out soaking, namely selecting soybeans, washing the selected soybeans, and adding water so as to carry out soaking; 2) carrying out pulp-
grinding, namely thoroughly draining the soaked soybeans, adding hot water, carrying out pulp-
grinding, and carrying out filtrating so as to obtain bean dregs; 3) carrying out inoculating, namely carrying out sterilizing, and carrying out inoculating with activated
kluyveromyces marxianus at an
inoculation amount of 3-10%; 4) carrying out first
fermentation, namely adding
sterile water, and carrying out shaking-table
fermentation at 25-32 DEG C at 100-150 r / min for 48-96 hours; 5) carrying out second
fermentation, namely raising the temperature to 40-50 DEG C, and carrying out shaking-table fermentation at 100-150 r / min for 20-40 min; 6) carrying out washing, namely carrying out filtrating, collecting
solid, carrying out washing with water of which the temperature is 65-75 DEG C, carrying out filtrating, and collecting the fermentation product; and 7) carrying out crushing, namely carrying out cooling,
drying and crushing so as to obtain the soybean
dietary fiber. The soybean dietary
fiber prepared by the preparation method has significantly improved
expansive force, oil-holding capacity and water-holding capacity; moreover, the soybean dietary
fiber has reduced particle size, so that, rough taste is improved.