DisplayTitle

Use of dietary approaches in control of chronic degenerative diseases such as hypertension have been on the rise. Sourdough fermentation continues to enhance product nutritional and functional properties through bioactive metabolites. In this study, the effect of lactic acid bacteria (LAB) starters (<i>L. plantarum, L. sanfranciscensis, L. brevis, L. crustorum</i> and <i>W. cibaria) </i>on angiotensin-I converting enzyme (ACE-I) inhibitory activity and emulsifying properties of soy sourdough fermentation were investigated. Using central composite design (factors varied: wheat bran, fermentation time and dough yield); based on ACE-I inhibitory activity, two formulas were selected: S1 (3% wheat bran) and S2 (0% wheat bran). All LAB strains adequately grew in both sourdoughs, S2 samples registered significantly (<i>P</i><0.05) higher total count compared to S1 samples. Only <i>L. plantarum </i>and<i> L. sanfranciscensis</i> fermented sourdoughs exhibited ACE-I inhibitory activity with S2 (S2LP 52.8%, S2LS 40.5%) having higher (<i>P</i><0.05) activity than S1 (S1LP 36.5%, S1LS 32.5%). Amino acid profiles and peptide molecular weight distribution were both determined by chromatographic methods. Seventeen amino acids were present in all; sourdoughs had higher amino acid levels (<i>P</i><0.05) than the control samples. All sourdoughs (S2>S1) had higher (<i>P</i><0.05) amounts of hydrophobic, aromatic, and branched chain amino acids than the control. Low molecular weight peptides in the range 0.2-3kDa were highest in S2 followed by S1 and least in the control samples. Compared with control samples, sourdoughs exhibited lower emulsifying activity and higher emulsion stability. The LAB starter type significantly affected the ACE-I activity and emulsifying properties of soy sourdough fermentation. <i>L. plantarum</i> and<i> L. sanfranciscensis </i>were the best strains and no wheat bran should be used in soy flour fermented by the two strains.