The bitter truth – now in genotype form!


Isn’t this a fantastic scenario: you’re sitting at your desk and a mysterious white powder floats through the air and lands on your face. Some of it lands on your lips and, being the risk-taking individual that you are who is apparently not averse to putting unidentified powders in your mouth, you taste it and immediately complain to your colleagues about how disgustingly bitter it is. The powder has landed on their faces too and they taste it too and… no, it doesn’t taste of anything, actually. It’s not bitter in the least, they say to you with suspicious eyes and 50% of their eyebrows raised. Well then, aren’t you quite the weirdo? Please take your imaginary bitter taste and go sit in the corner.

This is how they discovered that people can experience tastes quite differently from each other. It was only 1930 when A.L. Fox accidentally released some phenylthiocarbamide into the air in his lab while trying to create an artificial sweetener and it landed on the faces of his colleagues (good work!), and while some of them complained of its bitterness (you’d think that would be the least of their problems if they’re working in a lab where chemicals routinely drift onto their faces and into their lungs), Fox himself couldn’t taste the bitterness. It turned out that about 30% of people find phenylthiocarbamide tasteless, whereas the rest find it moderately to intensely bitter.

It’s not exactly uncommon knowledge now that the ability to taste bitterness varies from person to person and that this is down to genetics. A whole heap of studies over the years have looked at how genetic variants within the TAS2R family of genes mean that some people taste bitterness of particular substances more easily than others. For TAS2R38, the gene that codes for the protein that allows phenylthiocarbamide to be tasted, you can have one of three possible combinations of variants, allowing you to be either a non-taster, a medium taster, or… a supertaster, in which case you can taste that phenylthiocarbamide better than about 75% of the population! Well done, you.

So, like I was saying, we know bitterness perception varies from person to person due to genetics, but it’s kind of boring if you just look at that within the scope of “Oh, Person X can taste this very specific chemical really easily whereas Person Y can’t taste it at all”. Pretty limited relevance. The interesting part is how it affects behaviour — how well you can taste bitterness can affect how much you like particular foods, and that can have a reasonably big impact on eating behaviours.

Studies have been a bit inconclusive when it comes to bitterness gene variants and liking for somewhat bitter vegetables (such as broccoli, spinach, Brussels sprouts, kale and cucumber), with high-tasters of bitterness sometimes liking these vegetables more than low-tasters, and sometimes less. However, sensitivity to bitterness changes with age, so maybe you need to look at these things in particular age groups to get a clearer picture. Certainly, some studies have found that in children, non-tasters who aren’t so sensitive to bitterness find these vegetables more pleasant to eat than the tasters who are sensitive to bitterness, and non-tasters generally eat more vegetables than tasters. Some studies have found the same in adults.

Consumption of bitter fruits can also be affected by genes, with female adult supertasters finding a drink containing naringin (a compound from grapefruit peel) less pleasant, and the same went for just plain grapefruit juice. It looks like the intensity of the bitterness matters too, since taster children were no different from non-taster children when drinking a mixture of 25% grapefruit juice and 75% orange juice, but then the tasters disliked a more bitter mixture of 50% grapefruit juice and 50% orange juice compared to non-tasters.

So it all sort of makes sense — people who are more sensitive to bitterness kind of dislike things that are a bit bitter. However, the intrigue continues with research that has found that genetic variants for bitterness are also associated with different perception of sweetness and saltiness and sourness, the detection of the pungency or flavour of food, and also the ability to discriminate fat content in food and drinks.

But I will go into detail for those in future posts, and for now, you can make some Pimm’s Cup cupcakes. Complete with whipped lemonade and simulated cucumber! It’s a bitter orange and cucumber gel, cut into sticks, to which I attached real cucumber skin. Don’t you want to do something so convoluted and arduous too?

Read on for the recipe for Pimm’s Cup cupcakes.

Pimm’s & orange cakes
80g butter, at room temperature
1 cup caster sugar
2 eggs
zest of 1 large orange
60ml (2 shots) of Pimm’s
1/8 tsp salt
1 1/3 cups plain flour
3/4 tsp baking powder
1/2 cup buttermilk
1/2 tsp bicarbonate of sida
1/2 tbs vinegar

Preheat oven to 180°C. Line a muffin pan with paper cupcake liners.

Beat the butter and caster sugar together until fluffy and light. Add the eggs one by one, beating well after the addition of each egg. Add the orange zest, Pimm’s and salt and beat to combine.

Combine the plain flour and baking powder in a bowl and add this in halves, alternating with the buttermilk.

In a small bowl, add the vinegar to the bicarb and whisk with a fork so that there are no lumps. Add this to the cake mixture and beat reasonably quickly for 10 seconds.

Spoon the cake mixture into the cupcake liners, filling them about 3/4 full. Bake for about 12 minutes. Remove from the oven and allow the cakes to cool in the muffin pan for 15 minutes (they’re very delicate when warm) then remove onto a wire rack to cool completely.

Whipped lemonade
250ml (1 cup) lemonade
30ml (1 shot) Pimm’s
xanthan
methylcellulose

Add xanthan to the lemonade, combining using a stick-blender, until it is the consistency of thickened cream. Weigh this amount, then using an electric mixer, whisk in the methylcellulose – the amount will depend on your brand/purity of methylcellulose. For Texturas Metil, add 3% by weight. For other methylcelluloses (such as Methocel), you will probably need less, e.g. 1.25% by weight. Whisk the methylcellulose into the lemonade mixture at a high speed for about 15 minutes. The mixture will increase in volume a few times over.

This whipped lemonade is reasonably stable, and can be left at room temperature for a few hours without losing its aeration. It lasts a bit longer in the fridge, but will start to lose its aeration after a day or two in there.

Bitter orange cucumber gel sticks
zest and juice of 1 large orange
1 continental cucumber (about 300g)
bitters
agar

Grease a rectangular container (about 40cmx30cm) with non-stick spray.

Skin the cucumber and retain the skin, trying to keep it in strips as big as possible. Cut the flesh into large pieces.

Put the orange zest, orange juice and cucumber pieces in a blender. Add a few generous dashes of bitters (the bitters go amazingly well with cucumber — I’m definitely going to use this combination in other recipes in the future). Blend until smooth (may take a couple of minutes) then pour through a fine sieve to get a nice, smooth green liquid. Weigh this liquid. Place in a saucepan over medium heat and when it starts to steam, add in 1% agar by weight. Bring to the boil, stirring well, then pour into the rectangular container. Leave at room temperature for 2 hours to set.

Remove the cucumber gel from the container, being careful not to let it break (it’s reasonably flexible, so this shouldn’t be too much of a problem). Using a penknife, cut the gel into rectangles of the final size you want for your cucumber sticks. Lay one gel stick on a strip of cucumber skin and then use the stick as a template and cut the skin with the penknife to be the same dimensions as the stick. The moistness of the cucumber skin and the stick will allow them stick together pretty well.

To assemble the cakes: pipe the whipped lemonade onto the cooled cakes (or spread it on with a spoon), then top with a cucumber stick and a quarter of a glacé orange round.

References
Tepper, B.J. (2008). Nutritional implications of genetic taste variation: the role of PROP sensitivity and other taste phenotypes. Annual Review of Nutrition, 28, 367-388.

  16 comments for “The bitter truth – now in genotype form!

  1. October 31, 2010 at 9:44 am

    I remember reading about a “supertaster kit” in the US a few years back, with which you could test yourself to find out what kind of taster you were. The kit must’ve been using this chemical/compound thingy. I never did it myself, but I’d be tempted if I came across it now! I love vegetables (the “bitter” ones you’ve mentioned here like kale and brussels sprouts) but I also don’t like bitter grapefruit…

    Sadly, I’ve never had a Pimm’s, but I do have to say your faux-real cucumbers are awesome!

    • Jess
      November 1, 2010 at 10:52 am

      I think that sort of taster kit uses PROP, 6-n-propylthiouracil, rather than phenylthiocarbamide… maybe… I don’t know, PROP seems to be the cool, “in” thing when it comes to bitterness tasting these days. But I reeeeeally want to know what sort of a taster I am as well. It would be incredibly interesting, although ultimately useless in terms of interpreting whether I like something or not just because I can taste its bitterness or not. n=1, sigh.

  2. October 31, 2010 at 9:55 pm

    I remember reading about the tasting kit too Hannah. It certainly would be interesting to try.

    Wow, these cupcakes look fabulous Jess and I love the sound of the whipped lemonade. This all reminds me of the episode of Top Chef Just Desserts I watched last night where the chefs were challenged to turn famous cocktails into desserts. This blows any of their creations out of the water!

    • Jess
      November 1, 2010 at 3:17 pm

      Ooh, what sort of things did they do? I’ve made cocktails into desserts before (usually into cupcakes) because I just think it usually involves well-tested flavour combinations, and liqueurs/spirits make it easy to get a particular flavour into something like cake batter or icing. It’s definitely fun to try and interpret an existing recipe into a different format. I think that’s one of my favourite things to do with the things I bake – take one meal and make it into a completely different one. I like that sort of challenge. :)

    • November 1, 2010 at 3:32 pm

      The winning dessert was a Margarita inspired bombe with a lime cookie, tequila mousse and salt, which looked fantastic. Other desserts weren’t so successfully and didn’t really resemble the original cocktail. Another was a bourbon upside down pineapple cake, which while the judges loved the taste of looked very home cooked. While the show was good it was a bit hard to concentrate with one of the chefs all but having a major meltdown through the entire show. I’m hoping he gets eliminated soon.

  3. October 31, 2010 at 11:44 pm

    I have an enormous bottle of Pimm’s in my liquor stash that I bought duty free on my last overseas jaunt, ready to be enjoyed in my courtyard with my (English) housemate in the sunshine! I don’t know about her bitterness sensitivity, but this particular housemate of mine certainly has a taste for Pimm’s. I’d like to think that I would go to all this effort to make her Pimm’s cupcakes, and her birthday is coming up in December…. sigh, I guess it’s decided then. Best go buy myself a new Stanley knife.

    • Jess
      November 1, 2010 at 3:20 pm

      Pimm’s is just so delightful. It would be straight-forward and effective enough to just make a Pimm’s-flavoured cake with Pimm’s-flavoured icing for the Pimm’s afficionado in your life. Thicken the Pimm’s up with a bit of xanthan to make a Pimm’s jam then put that in a layer between two pieces of the Pimm’s cake.

      Pimm’s should really pay me for every time I mention Pimm’s. Pimm’s? Pimm’s!

  4. November 1, 2010 at 9:21 pm

    One thing we have NOT learned enough about in med school is taste. Which I think is tragic because I would have much rather learned about that than about the hearing system. I wonder where I fall on the bitter scale. I love grapefruits. Does that tell you anything?

    These cupcakes sound excellent!

    • Jess
      November 3, 2010 at 10:30 pm

      I guess having a taste impairment isn’t as limiting as having a sight or hearing impairment (and maybe isn’t as common), so there’s just not that much research (or research funding) for it. Sigh!

  5. November 2, 2010 at 6:56 am

    You seriously have the most creative desserts, Jess! I’d heard about differences in tastes between people but had no idea how it was discovered. My first reaction would probably have been ANTHRAX! And then we’d never have found out all this cool info 8p.

    • Jess
      November 3, 2010 at 10:32 pm

      I think plenty of people would have thought ANTHRAX! Whatever a mysterious powder floating on the air is, it most likely is not a good thing. A research institute would probably get shut down if something like that happened today…

  6. November 3, 2010 at 5:31 am

    Excellent. I really look forward to trying these — what a great use for Pimm’s.

    • Jess
      November 3, 2010 at 10:34 pm

      I’m very fond of Pimm’s but given it’s not hugely popular (at least in Australia — I’ll assume it’s much more popular in the UK) I having to keep inventing uses for it. Not complaining though!

  7. November 4, 2010 at 2:58 pm

    I love Pimms and lemonade, so I am keen to make these – umm, minus the fake cucumber.

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