The Miracle Fruit (Synsepalum dulcificum) is known for its “miraculous” berry.
When eaten, this berry causes sour foods (like a slide of lime) to taste sweet like lemonade. It also causes bitter foods to taste more palatable.
The effect is due to a molecule in the plant called “miraculin“. This molecule binds to the taste buds on your tongue. The effect lasts 30-60 minutes — it wears off when the miraculin is washed out the mouth by to salivation.
The miracle berry itself tastes mildly sweet, and it has low sugar content.
You can find Miracle Fruit powder on Amazon. I recommend using the powder rather than the tablets sold on Amazon — the tablets are grainy and difficult to dissolve in your mouth.
This article describes the use of Miracle Fruit in dieting.
Two More “Miracle Fruits”
There two other species of plant have the similar effects — Gymnema sylvestre — called “sugar destroyer” — makes sweet perception disappear — and Thaumatococcus daniellii — called “serendipity berry” — makes foods taste sweet).