Immobilization Of Lactobacillus Helveticus Proteinase And Successive Preparation Of ACE Inhibition Peptides

Lactobacillus helveticus proteinase could decompose whey protein to produce ACE(Angiotensin-? converting enzyme) inhibition peptides, which had anti-hypertension activities but amino acid sequences and lengths of the peptides were different with each other. To obtain large-scale production and industrial application of ACE inhibition peptides, the immobilization of Lactobacillus helveticus proteinase and the successive preparation of ACE inhibition peptide were studied in this paper.Gel embedding method was the commonly used immobilization method. The sodium alginate, gelatin, carageen glue and chitosan were choosed to immobilize proteinase. The experiment was evaluated by the operability, consuming time and cost. Finally, the sodium alginate was determined as the best carrier to immobilize Lactobacillus helveticus proteinase.Based on single factor experiment, the effects of calcium chloride concentration, glutaraldehyde concentration, sodium alginate concentration, and enzyme concentration on the activity of immobilized Lactobacillus helveticus proteinase were explored. The optimal immobilization conditions were determined by response surface analysis to be 0.1 mol/L calcium chloride concentration,0.39g/100 mL glutaraldehyde concentration,2.03g/100 mL enzyme solution sodium alginate concentration and 7.55 mg/mL enzyme concention. On this condition, the immobilized enzyme activity was 3.93 U/mg.Based on single factor experiment and response surface methodology, [S]/[E] ratio at 15 (w/w,%), pH at 7.5 and temperature at 37? were found to be the optimal conditions of immobilized Lactobacillus helveticus proteinase hydrolyzing the whey protein to obtain ACE inhibitory peptides. The ACE inhibitory activity of hydrolysates were close to 59.47% and DH of the hydrolysates were 6.08%.Lactobacillus helveticus immobilized with sodium alginate and Lactobacillus helveticus proteinase immobilized with sodium alginate were studied. Immobilized Lactobacillus helveticus proteinase was determined as filling carrier by sensory evaluation, activity evaluation and process evaluation.This paper designed two kinds of enzyme reactor for enzyme ultrafiltration reactor and packed-bed reactor. Ultrafiltration membrane, ultrafiltration pressure and feed supplement speed were researched. The ultrafiltration membrane at 6000 Da, ultrafiltration pressure at 0.05 MPa and feed supplement speed at 200 mL/h of 1.25% whey powder were choosed to be the optimal technological condition. The 1.2cm×80cm of packed column and the 3.2 mL/h of flow rate were the optimal technological condition for the fixed bed reactor. Compared to packed-bed reactor, the UF reactor was better for obtaining successive preparation of ACE inhibition peptide.