First, let’s begin with your tongue. Everyone’s tongue has five sections that detect certain tastes: sweet, sour, salty, umami, and bitter. Each section sends signals to your brain on the flavor profile of the food so you can taste that food.
There is a glycoprotein in Miracle Berries (called Miraculin) that attaches to the sweet taste buds on your tongue. Miraculin rewires the way your brain and tongue communicate. When the sweet receptors detect acids (the things that make foods sour), it will lower pH in your mouth causing Miraculin to undergo a transformation. They change the shape of the sweet receptors causing them to send sweet signals to your brain instead of sour.
Of course, this effect varies person to person because there are different factors such as the amount of Miraculin you’re consuming, how long it is in contact with your tongue, and the acid concentration of food you are eating. It is recommended to have the Miraculin (or Miracle Fruit Tablet) on your tongue for at least three minutes to allow this protein to dance with your taste buds.