Directed‐Vat‐Set starter producing ACE‐inhibitory peptides: Opimization and evaluation of stability

Angiotensin convening enzyme (ACE) inhibitory peptides can inhibit ACE effectively, which is crucial to regulating blood pressure. Many studies on the production of ACE-inhibitory peptides by probiotics, but few works have been carried out on Directed-Vat-Set (DVS) starter producing ACE-inhibitory peptides. In the study, The DVS starter producing ACE-inhibitory peptides were optimized using Lactiplantibacillus plantarum L69 (L69) and starter with Lactobacillus bulgaricus and Streptococcus thermophilus (Starter LS) through the single factor and the Box–Behnken design. The optimum conditions were: Addition of DVS starter is 0.20%, which is composed of Lactiplantibacillus plantarum powder and starter in the ratio of 1:1, cultivation time of 4.5 hr, fermentation temperature 42°C, and the response value were pH of 4.63, optical density (OD) of 0.759, ACE-inhibition activity of 87.20% in fermented milk. The accelerated storage test demonstrated that the inactivation rate constant of the DVS starter was k−18 = 4.24 × 10−3 at −18°C, indicating good stability. Practical applications ACE-inhibitory peptides have a significant antihypertensive effect and are safe without toxic side effects compared with ordinary antihypertensive drugs. In this study, Single-factor and Box–Behnken design were used to optimize the conditions of producing ACE-inhibitory peptides from DVS starter and the acceleration test was used to evaluate its stability. The fermentation time of DVS starter is shorter and the storage property is better. This study provided technical support for the development of DVS starter for functional dairy products.