Probiotic Characteristics of Lactic Acid Bacteria Isolated from Traditional Fermented Milk ‘Dahi’ in Bangladesh

We evaluated the probiotic characteristics (pH and acid production, acid and bile acid tolerance and Angiotensin I-converting enzyme (ACE) inhibitory activity) of lactic acid bacteria isolated from traditional fermented milk ‘Dahi` in Bangladesh. Among the tested strains, Lactobacillus delbrueckii subsp. bulgaricus M3 40-3 displayed more tolerance at acidic medium as well as highest acid production (2.13%). Whereas, highest ACE inhibitory activity (72.09±1.07%) was found in skim milk fermented with Streptococcus bovis J2 40-2. On the other hand, Lactobacillus fermentum B5 40-2 (95.53±0.79%) was exhibited strong bile acid tolerance followed by Enterococcus faecium D3 25-1 (88.66±0.76%), Lactococcus lactis subsp. lactis B4 25-3 (74.40±1.09%), Lactococcus raffinolactis D4 25-3 (72.34±1.20%) and Pediococcus pentosaceus B2 25-5 (65.67±1.58%). From the results obtained, Lactobacillus delbrueckii subsp. bulgaricus M3 40-3 might be used as probiotic starter culture for milk fermentation due to high acid production and tolerance at high acidic medium. Streptococcus bovis J2 40-2 is a unique strain detected as highest ACE inhibitory activity and suggest that it should be used as starter culture for probiotic fermented dairy foods.