Production of Angiotensin-I-Converting-Enzyme-Inhibitory Peptides in Fermented Milks Started by Lactobacillus delbrueckii subsp. bulgaricus SS1 and Lactococcus lactis subsp. cremoris FT4

Abstract

Two fermented milks containing angiotensin-I-converting-enzyme (ACE)-inhibitory peptides were produced by using selected Lactobacillus delbrueckii subsp. bulgaricus SS1 and L. lactis subsp. cremoris FT4. The pH 4.6-soluble nitrogen fraction of the two fermented milks was fractionated by reversed-phase fast-protein liquid chromatography. The fractions which showed the highest ACE-inhibitory indexes were further purified, and the related peptides were sequenced by tandem fast atom bombardment-mass spectrometry. The most inhibitory fractions of the milk fermented by L. delbrueckii subsp. bulgaricus SS1 contained the sequences of ␤-casein (␤-CN) fragment 6-14 (f6-14), f7-14, f73-82, f74-82, and f75-82. Those from the milk fermented by L. lactis subsp. cremoris FT4 contained the sequences of ␤-CN f7-14, f47-52, and f169-175 and -CN f155-160 and f152-160. Most of these sequences had features in common with other ACE-inhibitory peptides reported in the literature. In particular, the ␤-CN f47-52 sequence had high homology with that of angiotensin-II. Some of these peptides were chemically synthesized. The 50% inhibitory concentrations (IC 50 s) of the crude purified fractions containing the peptide mixture were very low (8.0 to 11.2 mg/liter). When the synthesized peptides were used individually, the ACE-inhibitory activity was confirmed but the IC 50 s increased considerably. A strengthened inhibitory effect of the peptide mixtures with respect to the activity of individual peptides was presumed. Once generated, the inhibitory peptides were resistant to further proteolysis either during dairy processing or by trypsin and chymotrypsin.

ACE-I inhibitory properties of hydrolysates from germinated and ungerminated Phaseolus lunatus proteins

“…The IC 50 values reported for hydrolysates from animal protein sources differ noticeably: 8-11.2 μg/mL for milk protein (Gobbetti et al, 2000) and 20-74.4 μg/mL for egg white protein (Miguel et al, 2007).…”

Proteolytic activity of dairy lactic acid bacteria and probiotics as determinant of growth and in vitro angiotensin-converting enzyme inhibitory activity in fermented milk

“…Similar results were reported by Pihlanto-Leppalla et al [31] using different lactic acid staters and digestive enzymes to obtain inhibition of 35 to 86% and IC 50 values between 0.080 to 0.314 mg·mL -1 . Several milk protein-derived peptides produced by the enzymatic hydrolysis [33] or by the fermentation of milk with different strains of organisms [18,23] inhibited the activity of ACE.…”

“…cremoris FT4 and L. delbrueckii ssp. bulgaricus SS1 [18,27]. These biologically active peptides include hypotensive peptides which inhibit angiotensin I-converting enzyme (ACE), opioid agonist and antagonist peptides, and mineral binding, immunomodulatory, antibacterial, and antithrombotic peptides [30,35].…”

ACE-inhibitory activity and ACE-inhibiting peptides in different cheese varieties

“…lactis ssp. cremoris FT4 [30], L. rhamnosus in combination with pepsin and Corolase PP [38], L. delbrueckii ssp. bulgaricus and Str.…”