French scientists tested the blend on pig arteries in the lab, and found it caused artery wall to relax.
It remains to be seen whether fruit juices can improve vascular health, they report in a scientific journal.
The study adds weight to evidence fruit and veg reduces heart disease risk, says the British heart Foundation.
The researchers looked for a chemical called polyphenol in friut and berries.
They found the most active fruits included blackcurrant, blueberry, aronia (choke berries), cranberry, ling on berry and grape.
Commenting on the study, Tracy Parker, heart health dietitian at the British Heart Foundation, said: "This research adds more weight to evidence that eating fruit and vegetables is good for us in terms of reducing our risk for heart disease".
"However, we still don’t fully understand why, or whether certain fruits and vegetables are better than others. Even this study acknowledges that scientists can’t yet explain any link.
"What we di know is that we should all eat a wide range of fruit and veg part of a balanced diet, and fruit juice is a tasty and handy way of doing this.
Don’t forget though, juice contains less fibre and more sugar than the original fruit so it only counts as one of our five-a-day".
The research was published in the Royal Society of Chemistry journal, Food and Function.