Antioxidative and ACE-inhibitory activities of skim milk fermented with thermophilic Lactobacillus isolated from traditional Indian sweet curd of West Bengal

Fermentation and storage are known to enhance the production of natural antioxidative and angiotensin-I converting enzyme (ACE)-inhibitory components in dairy products. In this study, the antioxidative potential (% ABTS and % DPPH inhibition) and ACE-inhibitory activity of fermented skim milk (fermented at 42°C for 24 h) using 10 Lactobacillus isolates, previously isolated and characterized from the traditional sweet curd of West Bengal, India were evaluated over a storage period of 7 days at 7 ± 2°C. Among all isolates, Lactobacillus delbrueckii subsp. indicus (JSL 2 P 2 ) exhibited the highest functional activity, with ABTS and DPPH inhibition levels of 14.57 ± 0.67% and 14.43 ± 0.72%, respectively, and ACE inhibition of 47.86 ± 1.95% after 24 h of fermentation. These bioactivities further increased during storage. The findings scientifically validate the health-promoting properties of traditional Indian sweet curd prepared with Lactobacillus delbrueckii subsp . indicus , highlighting its potential for commercial application in functional dairy product development and its role in reducing the risk of lifestyle-related diseases.