Mechanically defatted soybean flour is a residue of mechanical soybean oil expression. We tried to produce a low-fat soybean yogurt with probiotic activity using mechanically defatted soybean flour. Sixteen strains of lactic acid bacteria were examined for their growth in the fermented soymilk made from the mechanically defatted soybean flour, changes in survival rate in cold storage, and immunostimulatory activity. Production of lactic acid by the tested strains in the fermented soymilk was also determined. ① Thirteen strains grew well in soymilk made from the flour. Strain F47 exerted the highest lactic acid production among the tested strains, and the taste evaluation of the fermented soymilk was excellent. Therefore strain F47 was selected as a suitable bacterium for the fermentation of soymilk made from the mechanically defatted soybean flour. ② Strain H47induced the production of cytokines from macrophage-like cell line J774.1, indicating that this strain had an immunostimulatory activity. ③ Soymilk was fermented using strain H47 at 30℃ for 20 hours, and the viable cell count of strain H47 was more than 108cfu/ml. The fermented soymilk was stored at 5℃ for 7 days, and the viable cell count remained on the order of 108cfu/ml. Our study shows that it is possible to produce probiotic fermented soybean yogurt from mechanically defatted soybean flour.
