Probiotic Bacteria Working Together Produced More Blood Pressure-Lowering Peptides from Whey Protein | Research

The takeaway

Co-culturing two probiotic bacteria in whey generated more bioactive peptides and achieved 53% ACE inhibition — higher than either strain alone.

53.42% ACE inhibition
achieved by co-culturing two probiotic strains in whey — higher than either bacterium fermenting alone

What the researchers found

Co-culturing L. rhamnosus GG and S. thermophilus SY-102 in whey produced higher protein hydrolysis (453 μg/mL free amino groups), more low molecular weight peptides, and the highest ACE inhibition activity (53.42%) compared to either bacterium alone. The co-culture fermentation extended the logarithmic growth phase to 24 hours, enabling more extensive protein breakdown into bioactive peptides.

Why it matters

ACE inhibitors are among the most widely prescribed blood pressure medications. Discovering that probiotic bacteria can generate natural ACE-inhibitory peptides from whey protein during fermentation points toward functional food products that could support cardiovascular health through bioactive peptide delivery.

The numbers in context

53.42% ACE inhibition · 453 μg/mL free amino groups · 10⁸ CFU/mL initial concentration · co-culture growth phase 24 h · single cultures 6–12 h

How the study worked

Whey was fermented using L. rhamnosus GG, S. thermophilus SY-102, or both together, each starting at 10⁸ CFU/mL. Proteolytic profiles were analyzed using TNBS (free amino group quantification), SDS-PAGE (protein size separation), and SEC-HPLC (molecular weight distribution). ACE inhibition capacity was tested using an in vitro assay.

Who was studied

In vitro whey fermentation study with probiotic bacteria

What this study cannot tell us

ACE inhibition was measured only in vitro — the actual blood pressure-lowering effect of these peptides in humans is unknown. The peptides were not individually identified or characterized. Digestive stability and bioavailability were not assessed. The 53.42% inhibition rate is moderate and may not translate to meaningful clinical effects.

How to read the evidence

This is an in vitro food science study demonstrating ACE-inhibitory peptide production during fermentation. While the fermentation results are clear, the leap from in vitro ACE inhibition to actual blood pressure effects in humans requires extensive further study.

When this study was published

Published in 2023, this study contributes to the growing body of research on bioactive peptides from fermented dairy products, a field that has expanded significantly in the past decade.

The bigger picture

Food-derived bioactive peptides are an active area of research at the intersection of nutrition and medicine. ACE-inhibitory peptides from fermented dairy products could complement conventional blood pressure treatments. The co-culture approach demonstrates that fermentation conditions can be optimized to maximize bioactive peptide production, moving functional food development from chance observation to engineered design.

Questions still open

Would these ACE-inhibitory peptides survive digestion and retain activity when consumed as part of a fermented dairy product?
Which specific peptide sequences are responsible for the ACE inhibition, and how potent are they compared to pharmaceutical ACE inhibitors?
Could this co-culture fermentation approach be scaled to produce commercial functional dairy products?

Common questions

What are ACE-inhibitory peptides and why are they found in fermented dairy?

ACE (angiotensin-converting enzyme) helps regulate blood pressure, and blocking it lowers blood pressure — this is how common medications like lisinopril work. When probiotic bacteria ferment milk proteins, they break them into small peptides, some of which happen to block ACE. These natural peptide fragments are being studied as potential functional food ingredients.

Why did the two bacteria together produce better results than either alone?

The co-culture extended the active growth phase to 24 hours (versus 6-12 hours for single strains), allowing more time for protein breakdown. The two species likely have complementary enzyme systems that together cut whey proteins into a wider range of small bioactive peptides, resulting in higher ACE inhibition.

Read the original research

ACE-Inhibitory Activity of Whey Proteins Fractions Derived of Fermentation by Lacticaseibacillus rhamnosus GG and Streptococcus thermophilus SY-102.

Foods (Basel, Switzerland), 12(12)

View on PubMed ↗Publisher’s paper ↗

Citation

Olvera-Rosales, Laura Berenice; Pérez-Escalante, Emmanuel; Castañeda-Ovando, Araceli; Contreras-López, Elizabeth; Cruz-Guerrero, Alma Elizabeth; Regal-López, Patricia; Cardelle-Cobas, Alejandra; González-Olivares, Luis Guillermo. (2023). ACE-Inhibitory Activity of Whey Proteins Fractions Derived of Fermentation by Lacticaseibacillus rhamnosus GG and Streptococcus thermophilus SY-102.. Foods (Basel, Switzerland), 12(12). https://doi.org/10.3390/foods12122416