Three novel peptides from fermented milk showed potent ACE-inhibiting activity for blood pressure control, but simulated digestion significantly reduced their effectiveness.
27 novel pentapeptidesProbiotic fermentation of milk produced 27 new five-amino-acid peptides with ACE-inhibiting potential, though digestive stability remains a challenge for oral effectiveness
What the researchers found
From milk fermented with Lactobacillus delbrueckii QS306, researchers identified 27 novel pentapeptides (five amino acids each) with potential angiotensin-converting enzyme inhibitory (ACEI) activity. Of seven tested peptides, three — HLPLP, PYPQR, and VAPFP — showed the best ACE inhibition (lowest IC50 values). However, in vitro digestion simulation significantly reduced their activity, indicating poor stability against gut enzymes.
Molecular docking and dynamics simulations revealed these peptides inhibit ACE through hydrogen bonding and hydrophobic interactions at the enzyme's active site, providing a structural basis for their blood pressure-lowering potential.
Why it matters
High blood pressure is the leading modifiable risk factor for cardiovascular disease. ACE inhibitor drugs (like lisinopril, enalapril) are among the most prescribed medications globally. Discovering natural ACE-inhibiting peptides in fermented dairy products could lead to functional foods that help manage blood pressure through diet. The challenge — as this study reveals — is that many of these peptides are destroyed during digestion, which must be solved before they can be practical.
The numbers in context
27 novel pentapeptides identified · 7 tested for activity · 3 top performers (HLPLP, PYPQR, VAPFP) · Significant activity loss during simulated digestion · Molecular docking confirmed ACE binding
How the study worked
Milk was fermented with L. delbrueckii QS306 with and without ultrahigh-pressure treatment. Peptides were identified using UPLC-Q-Exactive-HF-X-MS/MS mass spectrometry. Bioinformatic analysis screened for ACEI potential. Selected peptides were synthesized and tested for ACE inhibition (IC50 values). Digestive stability was assessed via in vitro gastrointestinal simulation. Binding mechanisms were investigated using molecular docking and molecular dynamics simulations.
Who was studied
In vitro biochemical and computational study; no human or animal subjects
What this study cannot tell us
The three best peptides showed significant activity loss during simulated digestion, questioning their practical effectiveness when consumed orally in fermented milk. All testing was in vitro — no animal or human blood pressure studies were conducted. The ultrahigh-pressure treatment's specific impact on peptide generation versus activity was incompletely characterized in the abstract. The IC50 values and specific activity numbers were not detailed in the abstract.
How to read the evidence
This is an in vitro peptide discovery and characterization study with computational modeling. No animal or human blood pressure data was generated. The study provides mechanistic evidence but cannot confirm in vivo efficacy.
When this study was published
Published in 2023, this contributes to the active field of food-derived bioactive peptide discovery, using modern mass spectrometry and computational approaches.
The bigger picture
Food-derived ACE-inhibitory peptides represent the largest class of bioactive food peptides, with hundreds identified from dairy, soy, fish, and other proteins. The persistent challenge is digestive stability — many peptides that work in a test tube are destroyed before they can reach the bloodstream. This study exemplifies both the promise (potent new peptides with known binding mechanisms) and the limitation (poor digestive survival) that defines this field. Solutions may include encapsulation, resistant peptide design, or fermentation optimization.
Questions still open
- Can encapsulation or formulation strategies protect these milk peptides from digestive degradation?
- Would the ultrahigh-pressure treatment produce more digestion-resistant peptide variants?
- Do these peptides actually lower blood pressure in animal models or human studies despite their in vitro instability?
Common questions
Could fermented milk actually lower blood pressure?
What is ACE and why does inhibiting it lower blood pressure?
Read the original research
Screening, Characterization, and Mechanistic Evaluation of Angiotensin Converting Enzyme Inhibitory Peptides Derived from Milk Fermented with Lactobacillus delbrueckii QS306 with and without Ultrahigh-Pressure Treatment.
Journal of agricultural and food chemistry
Citation
Wu, Nan; Wuhanqimuge; Shuang, Quan. (2023). Screening, Characterization, and Mechanistic Evaluation of Angiotensin Converting Enzyme Inhibitory Peptides Derived from Milk Fermented with Lactobacillus delbrueckii QS306 with and without Ultrahigh-Pressure Treatment.. Journal of agricultural and food chemistry. https://doi.org/10.1021/acs.jafc.3c03752