Researchers have found that the enzyme polyphenol oxidase (PPO) in certain fruits like bananas can reduce the absorption of heart-healthy flavanols, especially when combined with flavanol-rich ingredients like berries. The study suggests choosing ingredients with low PPO activity, such as pineapple or oranges, when making smoothies to optimize flavanol absorption.
Ugh can’t even come to lemmy to escape real life - spent most of Monday morning denaturing/counteracting PPO in my uni food science lab!
Polyphenol oxidase is the enzyme responsible for browning in shit like apples and potatoes when cut and exposed to air.
I haven’t read the study linked in the OP yet (and I’m far too sad and intoxicated for it right now) but in other fruits/vegetables it’s pretty easy to deactivate PPO through application of some combination of Vitamin C (converts quinones back to their phenol form and reacts with oxygen before it can get to the PPO) and heat (which actually denatures the PPO enzymes).
When we were denaturing PPO in potatoes in a lab setting we simply blanched the sliced potatoes in 90°C water for 5 minutes before placing it in an ice bath until cool.
So basically, just add a bit of lemon juice to your smoothie?
I’m not confident saying for sure without reading the actual paper - it really depends on how PPO interacts with the flavanols, but at the end of the day denaturing the PPO with heat should make it a non-issue. Keep in mind though that bananas are far from the only smoothie ingredient with PPO!