Antioxidant, antihypertensive, and immunomodulatory activities of peptide fractions from fermented skim milk with Lactobacillus delbrueckii ssp bulgaricus LB340

The aim of this study was to evaluate the antioxidant, antihypertensive and immunomodulatory characteristics of skim milk fermented with Lactobacillus delbrueckii ssp. bulgaricus LB340. Supernatants obtained from the ferments after centrifugation were subjected to ultrafiltration and yielded four peptidic fractions of 10-5 kDa, 5-3 kDa, 3-1 kDa, and <1.0 kDa. Peptides in 5-3 kDa range exhibited a good antioxidant activity. The peptides (<1.0 k) was applied to Superdex-30 G column fractionation and produced six fractions (F1-6). Fraction F2 presented the highest angiotensin I-converting enzyme inhibition activity with IC50 of 67.71 +/- 7.62 mg/ml. Moreover, fraction F6, which displayed a good immunomodulatory activity, had a positive effect on murine spleen lymphocyte proliferation with Stimulation Index of 0.729 +/- 0.123. The present data showed the potential of the milk fermented with Lactobacillus delbrueckii ssp. bulgaricus LB340 as a functional food, however, further research is needed to evaluate the biofunctional activity of this fermentation product in vivo using model animal.