Airplane food is notoriously bad. But airlines, in financial free fall over the last decade, have been trying to bring back the luxe food of early flight in business class and first class, to lure in more high-end travelers. Biology is working against them, though. As Jad Mouawad reports for the NYTimes, part of why plane food lacks subtlety is that we can’t actually taste as well when we’re at altitude:
Even before a plane takes off, the atmosphere inside the cabin dries out the nose. As the plane ascends, the change in air pressure numbs about a third of the taste buds. And as the plane reaches a cruising altitude of 35,000 feet, cabin humidity levels are kept low by design, to reduce the risk of fuselage corrosion. Soon, the nose no longer knows. Taste buds are M.I.A. Cotton mouth sets in.
Your lungs know a bitter sensation when they taste one.
Yes, taste. In a Nature Medicine study, Stephen B. Liggett and company found receptors on the smooth muscle in the lungs that respond to bitterness, similar to the bitter taste buds on the tongue. And, Liggett found, the receptors’ reaction to bitterness is to relax the muscles, and therefore to expand airways. That was totally unexpected, he says, and opens intriguing possibilities for pulmonary treatment—for example, asthmatic symptoms could be treated by exposing these receptors to bitter compounds.
Like tastebuds on the tongue, the receptors react to bitterness, but unlike tastebuds they do not send any signals to the brain. The researchers thought the taste receptors might have evolved as a protection against toxic plants [Boston Globe]
Snooty wine pairing rules, such as the edict that one must only drink white wine with fish, now have a little data behind them, according to a new study. Researchers found a correlation between the high iron content of red wine and a nasty, fishy aftertaste when the reds are sipped with seafood. In the experiment, tasters ate a bit of scallop, tasted some wine and evaluated the aftertaste on a scale of 1 to 4. The diners found the unpleasant aftertaste was more intense with wines that had a higher iron content, the researchers say [Los Angeles Times]. The researchers were able to block the aftertaste by adding a compound that masks the iron.
The iron content of a wine depends on the composition of the soil in which the grapes were grown, the dust on the berry, contamination during harvesting, transportation, and crushing, and the conditions during fermentation [Telegraph]. The new research, published in Journal of Agricultural and Food Chemistry, suggests that some low-iron red wines are OK to drink with fish. While red wines tend to have more iron than whites, it varies according to the type of grape, country of origin, and vintage.
But the iron is only half the story. The researchers report that they haven’t yet isolated the compound in the scallops that reacts with the wine, but they suspect it’s an unsaturated fatty acid, which could be breaking down rapidly and releasing the decaying fish smell when exposed to iron [ScienceNOW Daily News].
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Image: flickr / yashima
Cracking open a cold can of Coke and taking a bubbling swig will have your taste buds dancing—and now scientists know why. A new study shows that cells in taste buds that respond to sour stimuli also seem to be the ones responsible for tasting the carbonation’s fizz [NPR].The fact that we can taste the carbon dioxide in a fizzing soda has previously puzzled scientists, since the human tongue is usually thought to only sense five flavors—bitter, sweet, salty, sour, and umami (also called savory). However, the new study, published in Science, shows that the sour taste buds have an enzyme that interacts with carbon dioxide, so it’s not the bursting bubbles that you taste, it’s the C02 itself.
The researchers discovered this tricky bit of chemistry by studying mice. They gave the animals sips of club soda or a little buzz of carbon dioxide gas and recorded how the tongue signaled the sensation to the brain. Both soda and the gas produced similar sensations. But when they tested mice bred to have no sour taste buds, the brain never got its sensory alert. Further probing uncovered the enzyme responsible [AP]. The mechanism should be the same in humans, according to the scientists.
Scientists have found another reason why the fizz in a glass of champagne is so important: Besides tickling the tongue and pleasing the eye, the bubbles also release aromatic compounds that they’ve dragged up from the liquid in the glass. A new study found that concentrations of certain chemical compounds are higher in the air just above the glass than in the actual champagne.
Wine expert Jamie Goode comments: “In the past, we thought that the carbon dioxide in the bubbles just gave the wine an acidic bite and a little tingle on the tongue, but this study shows that it is much more than this” [BBC News]. Smelling the chemical compounds enhances the overall flavor of the champagne, researchers say.
Using a fancy piece of chemistry equipment to study the chemical composition of wine, European researchers have one-upped the sophisticated palates of wine connoisseurs. The researchers used ultra high resolution mass spectrometry to sort through all the chemical compounds present in wines that had been aged in oak barrels, and found that for each wine, they could determine which French forest the oak was cut from. No other approach – analytical or sensory – has been able to significantly discriminate wines according to the species or the origin of the oak used for the barrels before, they say [Chemistry World].
The findings could prove useful to wine connoisseurs and historians, the researchers said, concluding that their findings produced “chemical representations of the way such noble nectar can shape, on the (tongue) of the wine taster, some of the outlines of the scene of its birth” [AP]. Similar analyses could also be used to detect wine fraud, the researchers noted.
Lab rats who were exposed to alcohol while in the womb had a skewed sense of taste and showed a marked preference for ethanol as young rats, researchers say. The findings may shed new light on why human studies have previously linked fetal alcohol exposure to increased alcohol abuse later in life, and to a lower age at which a person first starts drinking alcohol [New Scientist].
The taste of alcohol has both sweet and bitter components, and study coauthor Steven Youngentob wondered whether prenatal exposure could affect how rats respond to those elements. He gave young rats a choice between ethanol, sweet water flavored with sugar, and bitter water flavored with quinine. Those rats whose mothers had consumed alcohol while they were pregnant preferred ethanol and the bitter water. By contrast, rats who were not exposed to alcohol tended to plump for the sweeter alternative [Telegraph].
Being treated unfairly in a game triggers the same facial expression as stomach-turning tastes and images, a new study has found, suggesting that the brain mechanism of disgust evolved to help humans avoid not just rotten food, but also immoral behavior.
“Our idea is that morality builds upon an old mental reflex, said study co-author Adam Anderson…. “The brain had already discovered a system for rejecting things that are bad for it. Then it co-opted this and attached it to conditions much removed from something tasting or smelling bad” [Wired News].
When researcher Julian Asher goes to the symphony, he gets a sensory extravaganza. “When I hear a violin, I see something like a rich red wine,” says Asher…. “A cello is more like honey” [New Scientist]. Asher has a condition called synesthesia in which sensory information gets mixed in the brain; in Asher’s particular form, auditory-visual synesthesia, sounds cause him to see colors. Now, a study led by Asher may have uncovered the genetic source of the condition, which synesthetes say can be both a blessing and a curse.
The researchers collected DNA samples from 196 people who had auditory-visual synesthesia running in their families, they explain in the American Journal of Human Genetics [subscription required]. Asher expected to find a single gene associated with the condition, but scanning the genomes revealed that it was linked to four distinct regions, on chromosomes 2, 5, 6, and 12.
The region that was most strongly linked to synesthesia was an area on chromosome 2 that has also been strongly linked to autism. That doesn’t mean that the two conditions are related, per se, explained Ed Hubbard, a cognitive neuroscientist…. Instead, the common gene or genes are likely “more generally involved in how the brain gets built.” The study also pulled out a region on chromosome 6 that contains genes linked to dyslexia — especially interesting, “seeing as phonemes [the units of sound in language] and letters are two of the strongest synesthetic triggers,” Asher said [The Scientist].
Researchers have found specialized receptors on the tongues of mice that detect calcium, leading them to hypothesize that humans have the calcium-dedicated receptors, too. It may be time to add calcium to the types of tastes — sweet, sour, salty, bitter and savory — that can be detected by humans [HealthDay News].
But in another twist, most mice don’t like the taste, lead researcher Michael Tordoff says. Tordoff and his colleagues gave 40 different strains of mice a choice: They could drink water or a calcium-rich liquid. Most preferred water once they tried both. There was, however, one exception—a mouse strain called PWK actually preferred the calcium-enriched liquid. Those mice, it turned out, had a different version of genes that are responsible for taste receptors on the tongue [Scientific American].