Tag Archive for orange

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.

Taste in the face

There’s no art
to find the mind’s construction in the face.

Macbeth, Act 1 Scene 4

I might be going out on a limb when I suggest that Shakespeare probably wasn’t a neuroscientist. I’m sure I can find some Shakespeare conspiracy theorists to tell me how wrong I am and that Christopher Marlowe was also a talented geneticist in between writing Shakespeare’s work, but for that line in Macbeth to suggest that our faces do not betray our thoughts and feelings and intentions indicates clearly that Shakespeare had a very poor understanding of modern social neuroscience research between the 1970s and 2010. How embarrassing for him.

These are “Old Fashioned” snickerdoodles, based on the sweet and bitter taste combination of the Old Fashioned cocktail. (This recipe is from the book The Boozy Baker, which Dan bestowed upon me after returning from a social cognition workshop via NYC and San Francisco — thanks, Dan!) One interesting bit of research looking and both sweet and bitter tastes found some very intriguing results about how our faces react to those tastes, and also how changing our emotional state changes our ability to perceive tastes. Who would have thought — eating is tied in with feelings! (Hi to all the other emotional eaters out there. Let’s have a piece of cake to celebrate how interesting neuroscience research is!)

In a study by Greimel et al., researchers video-recorded people’s facial expressions as they were drinking either a sweet chocolate drink, a bitter quinine drink, or a bitter-sweet carbonated drink. (The chocolate drink was Müllermilch Schoko and the carbonated drink was Schweppes Bitter Lemon, if you’re planning on replicating this experiment in the comfort of your own home or laboratory.) The researchers later watched these videos and scored a range of particular facial movements (brow lower, lip press, upper lip raise, etc.) to see what people did with their faces when they tasted a bitter or sweet taste.

In a not highly surprising result, sweet and bitter tastes elicited different facial expressions. Bitter tastes warranted brow lowering and lip raising just prior to swallowing, then brow lowering and mouth opening after swallowing, and on the odd occasion, a smile, presumably by the people cynically amused by their unfortunate situation of having to drink something gross like quinine. Sweet tastes reliably resulted in lip sucking before swallowing, lip wiping after swallowing, and of course, smiling (including the Duchenne smile, which is when you smile with your eyes as well as your mouth — yes, it has a name!).

So the specifics are interesting but overall, none of this is all that surprising — we all make the faces too and we’ve all seen other people make the faces. But the other thing the researchers did was that after people had tasted all the different drinks, they were shown one of two movie clips. One group was shown a clip that was intended to make them feel happy, whereas the other group was shown a clip that was intended to make them feel sad. Then — they tasted the different drinks again.

And what did this show? It showed that changing someone’s emotional state makes them perceive tastes differently. More specifically, people who had watched the happy clip then found the sweet chocolate drink even sweeter and more pleasant. People who had watched the sad clip then found the sweet chocolate drink less sweet and less pleasant. How nice this chocolate drink tasted was dependent on whether the person was a bit happier or a bit sadder.

This was not the case, however, for the bitter-tasting drink. Watching the happy movie clip or the sad movie clip didn’t change people’s ratings of how bitter or unpleasant the drink was. A potential explanation of this is that sugary sweetness plays with the neural wiring of our emotions a bit more because the brain wants to reward us for seeking out energy-rich sugar by giving us a pleasant, hedonic experience after we eat something sweet. Bitterness, on the other hand, doesn’t really need that kind of emotional involvement. It might play a role in telling us what foods to avoid, since bitterness can be associated with toxins in the things that our ancestors might have been jamming in their mouths to see if they were any good for eating — but if something is bad for us, and it tastes bitter when we eat it, and then we get physically sick from it, that association between the bitter taste and physical sickness is an association that doesn’t need more subtle emotional prompting from the brain to make us realise to not eat the bitter berries next time or we’ll end up with our stomach contents on our feet. Bitterness also doesn’t reliably tell us much about nutritional value of food. So if we want to learn to avoid something that could potentially kill us, probably better to not just have our brains’ perception of that bad taste be susceptible to our emotional state (and probably better to have a more emphatic response to bad food, rather than our brains just making us a feel a little bit sad after eating something potentially deadly).

So the next time you’re on a hedonic quest for enjoyment through the wonders of cake, chocolate, ice-cream, whatever, pre-emptively enhance your experience by watching something heart-warming or hilarious. If you wish to adhere to the rigours of scientific research, you can even use the exact movie clip used in the experiment in elicit the happy state. It’s this one.

References
Greimel et al. (2006). Facial and affective reactions to tastes and their modulation by sadness and joy. Physiology & Behavior, 89, 261-269.

Recipe for “Old Fashioned” snickerdoodles under the cut.

Blood orange tart

This is dedicated to Hannah at Wayfaring Chocolate, whose aversion to orange means that she won’t have to add this recipe to her to-bake list! Maybe I need to change my PhD project to investigate aversion to orange, since people such as Hannah who tragically don’t enjoy orange clearly need some sort of intervention, and I want to help these poor souls whose lives are devoid of the sublime orangey beauty that we more fortunate people have received into our hearts as the orangey glow of orangetastic salvation. Orange be with you.

Like my yuzu tart, this tart is made using the lemon tart recipe from Exclusively Food, although substituting in blood orange juice and adding the zest of a blood orange to the filling after straining it and before putting it into the pastry casing. I also grated rather a lot of chocolate over the top (Scharffen Berger 62% Cacao Semisweet, courtesy of Tash who brought it back from the U.S. for me, amongst other fantastic cacao-related products, since you can’t get Scharffen Berger anywhere that I know of in Australia – thanks, Tash!).

Receive this orange tart into your pie-ous hearts, heathens!

Citrus fizz

I would say that this recipe is a bit of citrus overload, but then again I don’t think there’s any such thing. I sometimes have to restrain myself from cramming citrus ad infinitum into whatever I cook. I’m like a kid in a candy store with citrus, except to render that simile exceptionally bland, the child is very sober and restrained and the candy store is just the local fruit & vegetable store with its not amazingly diverse citrus range.

This recipe is adapted from the latest issue of Delicious, and originally called for six Meyer lemons. Having precisely zero Meyer lemons handy, I changed the recipe to involve input from lemon, navel orange, Emperor mandarin and ruby grapefruit. The fizz element comes from the addition of yeast, which reacts with fructose and glucose (which is produced from the sucrose in the sugar courtesy of the yeast enzyme invertase — ok, wanton science indulgence time is over now) to produce carbon dioxide and alcohol. So the mixture should be slightly carbonated and ever so slightly alcoholic, although the relatively short reaction time really keeps this minimal. I find that the carbonation is barely detectable really, except as a slight change in taste (since carbon dioxide has a faintly sour taste) but it’s a pleasant and interesting change rather than just having this be your standard jug o’ juice.

It takes a little while to prepare, but in all it’s not much effort and it’s worth it in the end.