Characterization of the angiotensin-converting enzyme inhibitory activity of fermented milks produced with Lactobacillus casei

Abstract

Our study assayed angiotensin-converting enzyme (ACE) inhibitory activity and fermentation characteristics of 41 food-originated Lactobacillus casei strains in fermented milk production. Twenty-two of the tested strains produced fermented milks with a high ACE inhibitory activity of over 60%. Two strains (IMAU10408 and IMAU20411) expressing the highest ACE inhibitory activity were selected for further characterization. The heat stability (pasteurization at 63°C for 30 min, 75°C for 25 s, and 85°C for 20 s) and resistance to gastrointestinal proteases (pepsin, trypsinase, and sequential pepsin/trypsinase treatments) of the ACE inhibitory activity in the fermented milks produced with IMAU10408 and IMAU20411 were determined. Interestingly, such activity increased significantly after the heat or protease treatment. Because of the shorter milk coagulation time of L. casei IMAU20411 (vs. IMAU10408), it was selected for optimization experiments for ACE inhibitory activity production. Our results show that fermentation temperature of 37°C, inoculum density of 1 × 10 cfu/g, and fermentation time of 12 h were optimal for maximizing ACE inhibitory activity. Finally, the metabolite profiles of L. casei IMAU20411 after 2 and 42 h of milk fermentation were analyzed by ultra-HPLC electron spray ionization coupled with time-of-flight mass spectrometry. Nine differential abundant metabolites were identified, and 2 of them showed a strong and positive correlation with fermented milk ACE inhibitory activity. To conclude, we have identified a novel ACE inhibitory L. casei strain, which has potential for use as a probiotic in fermented milk production.

Production of Bioactive Peptides by Lactobacillus Species: From Gene to Application

“…Moreover, other Lactobacillus species may also release new ACE inhibitory peptides, as reported for some Lb. casei strains ( Li et al, 2017 ).…”

“…The Peptigram software could be used for peptidomics data visualization ( Manguy et al, 2017 ). Moreover, different computational representations or statistical analyses can be used to assess peptide distribution among different samples or conditions as the Venn diagram, the principal component analysis (PCA), multiple linear regression (MLR), artificial neural networks (ANNs), or partial least square-discriminant analysis (PLS-DA) ( Iwaniak et al, 2015 ; Dallas et al, 2016 ; Jin et al, 2016 ; Li et al, 2017 ). Therefore, peptidomics will be able to establish correlations between the CEP genotype of the strains and the profile of peptides they generate.…”

“…Peptidomics tools (chromatography, mass spectrometry, and bioinformatics) allow to analyze more rapidly and more accurately the heterogeneity of peptides produced through fermentation. Using computational methods (PCA, MLR, ANNs, and PLS-DA) ( Dallas et al, 2016 ; Jin et al, 2016 ; Li et al, 2017 ), it is possible to visualize which protein regions are preferentially hydrolyzed by different lactobacilli and their CEPs. However, statistical tools are needed to deal with the large datasets generating by peptidomics as thousands of peptides can be identified in a single sample ( Dupont, 2017 ).…”

Integrated Continuous Bioprocess Development for ACE-Inhibitory Peptide Production by Lactobacillus helveticus Strains in Membrane Bioreactor

“…Angiotensin converting enzyme-inhibitory activity in Lactobacillus fermented products was already reported (Fernandez et al, 2017;Georgalaki et al, 2017;Kliche et al, 2017;Solanki et al, 2017;Alhaj et al, 2018), and numerous ACE-inhibitory peptides have been identified (Pihlanto, 2013;Li et al, 2017). In this study, ACE-inhibitory activity was assessed by a biochemical test performed on samples, and predicted using a QSAR model on peptides identified by LC-MS/MS.…”

“…However, the industrial BAP production is still suffering from a lack of suitable large scale technologies (Wu et al, 2013;Agyei et al, 2016). Usually, fermented milks are prepared from batch fermentations without pH control generally resulting in yogurt-like, coagulated products (Li et al, 2017). In this case, optimization of BAPs production is difficult because of the absence of controlled conditions during the fermentation process.…”