Antithrombotic and ACE-inhibitory activity of milk fermented by <i>Lacticaseibacillus rhamnosus</i> GG and <i>Lactobacillus delbrueckii</i> ssp. <i>bulgaricus</i>

Abstract In this work, the antihypertensive and antithrombotic activities of milk fermented with Lacticaseibacillus rhamnosus GG and Lactobacillus delbrueckii ssp. Bulgaricus NCFB 2772 (monoculture and co-culture), were studied. It was observed that both species, as well as the co-culture, showed an increase in proteolytic activity during fermentation, which is related to the increase in the biological activities studied. Both biological activities increased as a function of fermentation time, describing a curve similar to that of their proteolytic activity, which could indicate the release of bioactive peptides due to the proteolytic activity of the bacteria. The highest antihypertensive activity was obtained at 12 h of fermentation and was 74.9% for Lb. rhamnosus, 79.1% for L. delbrueckii and 77.6% for the co-culture, with no significant difference between these values. On the other hand, the antithrombotic activity was 56.1% for Lb. rhamnosus, 49.9% for L. delbrueckii and 72.3% for the co-culture. These findings contribute to the knowledge about the influence of fermentation conditions on biological activity of fermented milk, while emphasising the additional benefits of probiotic and industrially important lactic acid bacteria.