ACE-inhibitory activity and gamma-aminobutyric acid content of fermented skim milk by Lactobacillus helveticus isolated from Xinjiang koumiss in China

Eighty-one strains of Lactobacillus were isolated from the koumiss collected in Xinjiang, China. The strains were cultivated in skim milk medium, ACE inhibitory activity and GABA concentrations in the culture supernatants were measured. Screening results revealed that ACE inhibitory activity of 16 strains was higher than 50% and two strains produced GABA. The Lactobacillus-ND01 strain produces both the high ACE inhibitory activity and GABA. The sequence of 16S rDNA of the Lactobacillus-ND01 showed 99% homology to L. helveticus. The first identification of the newly isolated Lactobacillus-ND01 strain which produces both high ACE inhibitory activity and GABA revealed differences from reported species in our study. The L. helveticus ND01 was resistant to acidic condition. The results suggest that L. helveticus ND01 showed good potential for application in the management of hypertension.