Profiles of isoflavone and fatty acids in soymilk fermented with Lactobacilli, Bifidobacteria, or Streptococci

Distribution of isoflavones and fatty acids in soymilk fermented with 7 Lactobacilli (L-type), 7 Bifidobacteria (Btype), or 5 Streptococci (S-type) were monitored. Total isoflavones in fermented soymilk ranged from 5.24 to 8.59 μmol/g dry basis while those in unfermented soymilk were 8.06 μmol/g dry basis. Depending on the types of inoculated microorganisms, fermented soymilk showed different profiles in isoflavones, especially aglycones and β-glucosides. Four L-type fermented soymilk had significantly higher aglycone content (33.69-46.21%) and low β-glucosides compared to control (p<0.05). All Btype fermented soymilk showed significantly high aglycone levels (p<0.05). Out of 5 Streptococci, 4 strains produced over 82.2% aglycones. Lipid content ranged from 162 to 224 mg/g and linoleic acid was the highest, followed by oleic, linolenic, palmitic, and stearic acids. Average ratio of unsaturated to saturated fatty acids in control, L-, B-, and S-type fermented soymilks was 6.30, 6.09, 6.30, and 5.94, respectively. This study can help to develop a fermented soymilk containing high isoflavone aglycones and low fat content.