Abstract: In this study, Lactobacillus helveticus was immobilized using sodium alginate and used to product yogurt with ACE inhibitory activity. As determined using one-factor-at-a-time method in combination with an L9(34) orthogonal array design, the optimal immobilization conditions were sodium alginate concentration 1.5 g/100 mL, cell concentration 1:10 (m/V), CaCl2 concentration 0.1 mol/L, and immobilization time 1 h. The immobilized strain and traditional yogurt starter consisting of Lactobacillus bulgaricus and Streptococcus thermophilus were used together to ferment 11 g/100 mL milk power solution at 37 ℃ until coagulation was completed. Good coagulation was achieved after 8 h of fermentation. The pH of the yogurt obtained with a gentle and smooth taste was 4.2 and the ACE inhibitory activity 70.3%.

Key words: immobilization, sodium alginate, Lactobacillus helveticus, ACE inhibitingactivity