Using Probiotic Bacteria for Soymilk Fermentation

Document Type : Original Article


1 Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Egypt

2 Special Food and Nutrition, Food Science Technology Institute Research, Agricultual Research Center, Egypt


Five probiotic bacterial strains (Lactobacillus plantarumATCC 14917,Lactobacillus
DSM 20011, Lactobacillus acidophilus ATCC20552, Lactococcus thermophilus DSM 20259,and Bifidobacterium longum B41409) were used as monoculture, and combined with them as co-cultures for the fermentation of soymilk. The total number is 20 co-cultures, separated similarly into two parts, the first half of each co-culture consisted of two strains, and the second half of each co-culture consists of three strains. The findings revealed that these cultures were capable of fermenting soymilk at only 8 h with a pH drop of between 4.42 and 4.89. Among 25 cultures, eight cultures (3 monoculture of L. plantarumATCC 14917 (C1),Lc. thermophilusDSM 20259 (C4), and B. longum B41409 (C5) and co-cultures of two strains L. plantarum ATCC 14917+ Lc. thermophiles DSM 20259 (C8) and of three strains L. plantarum ATCC 14917 + Lc. thermophilus DSM 20259 + B. longum B41409 (C18), L. plantarum ATCC 14917+ L. caseiDSM 20011+ Lc. thermophilus DSM 20259 (C19), L. caseiDSM 20011+ L. acidophilus ATCC20552+ Lc. thermophilus DSM 20259 (C22), and L. acidophilus ATCC20552+ Lc. thermophilus DSM 20259 + B. longum B41409 (C25)) which recorded the greatest significant viability of bacterial cells, titratable acidity, total organic acids (lactic, acetic, and propionic acids) contented, and pH in fermented soymilk ranged from 9.26 to 9.98 Log CFU/mL, 3.06 to 3.32 %, 19.90 to 18.40 g/L (lactic acid), 13.30 to 12.30 g/L (acetic acid), and 16.35 to15.00 g/L (propionic acid), and 4.38 to 4.62. The soy yogurt produced from the selected fermentation of soymilk was more preferred in the chemical composition of protein, carbohydrate, and fat contents than non-fermented soymilk.So the results show that the integrative use of probiotics may achieve the nutritional value of soymilk after fermentation had been improved by probiotic strains, therefore, making it a more health-beneficial functional food.