These lemons, they're completely normal, but we did alter the taste buds of these PBS hosts-
Lemon. -just a little bit.
All right.
I love lemons, so let's see how this goes.
Today on Reactions, we're investigating the sweet and sour secrets of the miracle berry.
Well, if I knew it was going to taste sweet.
Whoa.
Oh, my God.
It tastes like it is covered in sugar.
It's coated in sugar.
It tastes like lemonade.
Like straight up lemonade.
That's so intensely sweet.
Tastes like a super sweet kumquat.
You've probably seen videos like this- Today I'm going to be eating this miracle
berry and then eating this extremely, extremely spicy noodle.
-in which people eat increasingly ridiculous things to see if miracle berries change their
flavor, and that got us wondering, do miracle berries have limits?
As it turns out, the answer is yes.
Yes, they do.
That tastes pretty normal.
And we think we might know why.
I am going to eat this whole Oreo, though.
First things first.
This is your tongue.
This is a taste bud.
These are gustatory cells.
Gustatory cells, also known as a taste receptor cells.
Every taste bud contains taste receptor cells for all the basic tastes; sweet, sour, bitter,
salty and umami.
So that tongue map that you learned about in middle school, in which every taste is
limited to a specific region of your tongue, that's wrong.
Each of these gustatory cells has proteins that detect its specific taste.
This is the protein that lets you taste sweet.
When sugar or other sweet things bind to the outside part, the protein changes shape.
Yes, on the inside of the cell too, and that starts a signal cascade, which ends by telling
your brain, "Dude, sweet."
Miracle berries hijack this process.
Scientists think it works like this.
First you have to eat a miracle berry or miracle berry pill, both of which contain a protein
called miraculin.
We gave your favorite PBS hosts miracle berry pills.
Can I go for it?
Go for it.
Okay.
As you let the pill dissolve in your mouth, miraculin binds to the sweet taste receptor
and then nothing happens because miraculin by itself doesn't change the shape of the
receptor protein, so you taste basically nothing.
But when you eat something sour like this lemon-
A lemon! -the acid in the lemon interacts with the
sweet receptor protein and the miraculin, causing the protein to change shape, just
like when sugar binds, so you taste sweet.
It's like a lemon gumdrop, very sugary.
Humans have known that miracle berries plus sour things equal sweet for hundreds of years,
but in 1969 a few scientists tried to get a more specific handle on exactly which sour
things tasted sweetest after eating miracle berries, so they had people taste a bunch
of different acids; lactic, which is in sour milk, oxalic, which is in rhubarb, acetic,
which is what makes vinegar sour, but also formic acid, which is in bee and ant venom,
and hydrochloric acid, which is the same acid that's in your stomach.
Just a little safety note from us here at ACS, please do not put hydrochloric acid in
your mouth.
1969 was a different time, I guess.
Anyway, they discovered that hydrochloric acid, the strongest acid they tested, didn't
taste nearly as sweet as acetic acid.
Weak acids like the citric acid found in lemons tend to work better than strong acids like
hydrochloric, which is good for the health of your mouth.
More recent research has revealed that miraculin somewhat blocks sugars from binding to the
sweet receptor, which means that sweet things that have no acid in them taste kind of flat.
It's like less-sweet Oreo.
It's like the cream just disappeared and all you have is cookie.
As far as we know, miraculin only binds to the sweet receptor, and because you have taste
receptor proteins for a wide variety of tastes, most other flavors remain the same.
The food might just taste a little sweeter.
It still tastes like mustard but it's sweeter.
It's like a honey mustard.
The spiciness of capsaicin is still there, for example-
So, definitely still tastes spicy.
You still get the heat.
It's still kind of hot.
It's like a sweet chili sauce.
Mmmm. -and the tomatoiness of a tomato.
Whoa.
They taste like they're candied.
Gross.
Oh, my God, I can't believe I'm doing this.
So unless you actually like the taste of the food to begin with, don't expect an actual
miracle.
Ugh.
Still tomato.
Still gross.
Sorry.
If you want to learn exactly why 15 packets of red hot spiciness is so spicy, we've got
you covered.
Happy eating, and we'll see you next week.