Investigation On Peptides And ACE Inhibitory Activity In Lactobacillus Helveticus Fermented Milk

The angiotensin converting enzyme (ACE) inhibiting activity of Lactobacillus helveticus fermented milk and its whey was determined in this paper, and their effects on blood pressure were investigated using spontaneously hypertensive rats. As Lactobacillus helveticus TUST005 showed higher ACE inhibitory activity than Lactobacillus helveticus B02, the technical parameters of Lactobacillus helveticus TUST005 fermented milk were optimized through the single factorial and orthogonal experiments according to its ACE inhibitory activity. Reconstituted skim milk (13%) was inoculated with 3% (V/V) starter, and incubated under different temperature and time. Using ultrafilter treated the whey of fermented milk. The inhibitory activity of the sample at 42℃for 6h reached to 35.71%, and the highest inhibitory activity of the sample stored at 4℃for 3d reached to 45.91%. The sensory evaluation results confirmed the above sample with good coagulation, moderate acidity and higher acceptability.The effects of Lactobacillus helveticus fermented milk and its centrifugal /ultrafilter prepared whey on blood pressure and heart rate was evaluated with 8 week old spontaneously hypertensive rats (SHR) weighing 180-200 g. Every sample was used to SHR on consecutive 3 d, during which they received increasing doses by gastric intubation. Water was used for control administration. The systolic blood pressure, diastolic blood pressure and heart rate were measured by ZH-HX-Z tail cuff with a programmed electro-sphygmomanometer. At 15 mL per kg body weight dose of Lactobacillus helveticus TUST005 fermented milk and the 20 mL per kg body weight dose of Lactobacillus helveticus TUST005 fermented milk whey, we observed a marked and long-lasting antihypertensive effect for 6 h. Compared to that of control SHR, the maximum decrease in mean arterial blood pressure (20.2 mmHg) was achieved. Compared to that of the control SHR, the 20 mL per kg body weight dose of Lactobacillus helveticus B02 fermented milk and the 10 mL per kg body weight dose of Lactobacillus helveticus TUST005 fermented milk whey, which elicited a significant decrease in heart rate (maximum of 60.2 bpm and 50.2 bpm, respectively) were observed. Therefore, significant reductions in mean systolic blood pressure, and heart rate were observed following intra-gastric administration of Lactobacillus helveticus TUST005 fermented milk.In conclusion, Lactobacillus helveticus TUST005 fermented milk exhibits antihypertension and heart rate reducing activities. In order to demonstrate the mechanism, the Lactobacillus helveticus TUST005 fermented milk should be further studied in clinic.