Smithsonian.com

On your tongue, the glutamate molecule would sit right in the pink part. Image by Flickr user Robyn Gallagher

It’s called the “fifth taste,” and it’s loved, feared, and innocently sprinkled on food the world over, even though many people believe it’s a peculiarity of Asian food. I’m talking about umami, the savory essence of seaweed, dried fish, mushrooms, yeast, meat, cheese, tomatoes, and many other tastes.

And yet, ubiquitous as it is, it took until the early twentieth century for a Japanese chemist to isolate umami and recognize it as the fifth fundamental human taste—joining the select company of sweet, sour, salty, and bitter. In an endearing bit of science history, the discoverer, Kikunae Ikeda, named the substance umami—Japanese for “yummy.”

You may know the flavor better as monosodium glutamate (MSG), the infamous synthetic form of glutamate, the chemical largely responsible for umami taste. Glutamate is an amino acid that occurs as a building block in many proteins (it’s actually one of the most common neurotransmitters in the human body). But it only triggers the umami taste when it reaches the tongue in a free state, unbound to other molecules.

This week, scientists writing in the Proceedings of the National Academy of Sciences have puzzled apart the way glutamate activates nerves on the tongue. The findings help explain why umami taste can be accentuated by the addition of either of two other compounds: inosinate (found in meat) or guanylate (found in mushrooms).

Scientists call what happens during umami tasting a “Venus flytrap” mechanism: Glutamate lands on your tongue and nestles into a glutamate-shaped depression on an umami receptor. Upon contact, the receptor—an enormous, folded protein—changes shape and grasps the glutamate. That shape change also activates the neuron that tells your brain you are tasting umami.

The scientists also learned that inosinate and guanylate can bind to a separate part of the umami receptor. Once bound, they tighten the receptor’s grip on glutamate, increasing its ability to “taste” glutamate by up to 15-fold before the receptor relaxes its grip. The finding explains, perhaps, why a good Japanese broth contains both glutamate-rich seaweed and inosinate-rich dried fish flakes.

MSG—and by extension, umami—has gotten a bad rap over reports of people getting headaches or tingling sensations in the head and neck after eating foods containing the additive. But the FDA has not been able to identify MSG as the cause of such symptoms (so-called “Chinese restaurant syndrome”).

Even more reassuring than the FDA’s pile of inconclusive medical studies are the legions of people who blithely eat glutamates every day, the world over, in the form of hydrolized soy protein and yeast extracts. As a properly raised half-English kid, I spread glutamates on my toast every time I enjoy some delicious Marmite. When I settle in to watch Doctor Who reruns, the savory-cheesy nutritional yeast I sprinkle on my popcorn is glutamate central.

And it’s not just niche foods. Ever wonder what compels you to eat an entire bag of Doritos all by yourself? They may not contain MSG, but they’re packed with five separate sources of glutamate.

Head over to Umami Mart for more examples of this great flavor. (Star UM-er Kayoko has been on an umami binge in Japan for several weeks now, and I’m getting to the point where I’m too envious to keep reading her posts.)

Fewer wines wind up in barrels than you might think. Image: Wikipedia

With the holidays in full swing, it’s time to get serious about wine — something I regard as recompense for spending ages indoors with people I love dearly but who live in inconvenient parts of the country and tend to have very enthusiastic dogs.

And yet I’m hopeless at it. My experience with wine involves tiptoeing through rack upon rack of confusingly organized bottles, praying that my bag doesn’t knock over anything behind me while I look for some ideal intersection of price, label artwork, and name unpronounceability.

I used to read the descriptions printed on little squares of paper and taped to the shelves. But after several years I realized that all wines score between 87 and 92, and that pretty much any flavor is desirable as long as it isn’t grape. The less edible-sounding, the better: Bring on the vanilla, earth, leather, oak, pepper, orange peel, menthol, musk, and—no, I’m not kidding—farm yard.

So imagine my surprise to learn that many of these flavors come not from the pressed grapes but from the barrels they were stored in before bottling. And that owing to the high price of barrels, many high-volume winemakers skip the barrel altogether, opting instead to dunk bags of oak chips into their stainless-steel vats.

What sounds at first like an unconscionable shortcut starts to make sense when you look at the numbers. A prized, 60-gallon French-oak barrel can run winemakers $1,000. Do the math: the American wine industry produced 3 billion liters, or 13 million barrels’ worth, this year. Worse, the best barrels are made from oaks more than a century old (according to Jancis Robinson), and lose much of their flavor after their first use.

Good oak barrels affect wine in a few crucial ways. They help moderate the tannins that make wine astringent, reduce the taste of grapes, and intensify the color. They let in oxygen, which helps stabilize the wine while it’s young (even though oxygen destroys wine once it’s bottled). And they impart many of those unexpected flavors you read about in tasting notes. Some (vanilla and coconut, for example) come straight from the oak. Caramelized flavors come from the inside surface of the barrel, which is burned or “toasted” during building. Still other flavors appear when molecules from the oak react with complex sugars from the grapes to produce new aromatic compounds.

Industrial-scale winemakers realized they could do much the same thing by suspending bits of oak in their wine as it ferments. It’s cheaper as well as faster. Instead of keeping wine in a barrel for a year while it develops, oak chips can infuse a wine with the same compounds in a matter of weeks. And presumably, winemakers can now tinker with their oak-chip concoctions to get the flavors they most want.

I understand the rationale, and yet now I have this disturbing mental image of my wine being invaded by those bags of potpourri that perfume the bathrooms of my excessively neat relatives. Is that how all of these $12 wines come to be bursting with vanilla and leather? Is my favorite bottle of red, at heart, any different from a Yankee Candle? I think I’m being cultured, but am I really drinking some overspiced, oenological version of instant ramen soup?

Note: This post was written with the aid of a lovely 2004 Côte du Rhône syrah-grenache. The E.U. only began allowing so-called “oak alternatives” in 2006, so presumably this one had actually spent some time in a barrel.

Pacay leaves and pod, courtesy Anya Hinkle/UC Berkeley

Close on the heels of news about Ötzi the iceman’s final meals come revelations about a diet even more ancient. New findings show that about 8,000 years ago, the inhabitants of the Nanchoc Valley in the lower Peruvian Andes were eating beans, peanuts, domesticated squash, and a fruit pod called pacay, whose sweet white lining Peruvians still enjoy today.

That comes as surprising news for anthropologists. Eight thousand years ago is back in the hazy dawn (or at least early morning) of agriculture, when people around the globe were just starting to figure out how to cultivate plants. Before the publication of this new evidence (last week in Proceedings of the National Academy of Sciences) researchers thought agriculture had taken another 2,000 years to develop in Peru.

How do you find out exactly when a people started eating peanuts and squash? If you’re Dolores Piperno, of the Smithsonian Tropical Research Institute, and Tom Dillehay, of Vanderbilt University, you look at their teeth. Specifically at the calculus, which is that hardened plaque around your gumline that your dentist is always scolding you about. Tiny bits of food get caught up in that calcified bacterial sludge, where they can remain for millennia without disintegrating. And people like Dolores Piperno can identify them.

Piperno examined 39 teeth that date from a 1,000-year period at a Nanchoc archaeological site Dillehay had been working on. Her identification methods consisted of patiently training her microscope on grains of starch caught in the calculus. Despite being less than one-twentieth of a millimeter across, many of these grains were distinctive enough for Piperno to identify them to species. (It’s not unlike the idea of using feather fragments to ID python meals: sounds logical but unimaginably hard.) Piperno could even tell that some of the food, particularly the beans, had been cooked before it was eaten. The cooked grains were gelatinous and matched the appearance of bean starch she had cooked in her laboratory for comparison.

Earlier archaeological work in the Nanchoc Valley had turned up evidence of people cultivating plants, but scientists weren’t sure whether they had been used for food or other purposes. For instance, a squash plant might have been just as useful for gourds as for making baked squash for supper. The new work establishes that people had been eating their crops, and provides evidence that they already had a fairly diverse set of plants to cook with.

I like thinking of ancient people sitting around the Nanchoc Valley enjoying a stew of beans and peanuts and soft chunks of squash. Too often when I imagine early meals, it’s depressing: grimy, shivering figures gnawing at barely warmed flesh, cracking their teeth on nuts or patiently chomping some gritty tuber into submission.

There’s something comforting, too, about the thought that we’re still enjoying these same plants today. I had a great lamb stew recently, with beans and potatoes stewed until they were creamy and infused with flavor. It’s tempting to think the Nanchoc people ate something similar, perhaps watching the evening sun light up the Andes peaks and looking forward to a sweet dessert of pacay, nibbled from a pod and passed around the family circle.

Idyllic as it all sounds, there’s one last lesson here: the importance of brushing your teeth. It’s bad enough to walk around with bits of your last meal stuck in your teeth. You don’t want to broadcast your lunch to people 8,000 years in the future, do you?

Edible guitar cake, courtesy of Flickr user Omar de Armas

Over at Hungry Magazine there’s a fun review of Lost in the Supermarket, a valiant attempt by two writers to shed some light on the cuisine of the rock star.

It’s a great idea. Rock life can’t run entirely on gin, cigarettes and Cheez-Its, can it? Surely, every once in a while there must be something solid—something that starts out as a mere ingredient, or at least gets unwrapped, covered in cheese, and stuck into a toaster oven? And there you have it—preparation plus augmentation: the humble beginnings of a cuisine.

As it turns out, some bands can do considerably better than that. The Scottish band Belle and Sebastian roll out a veggie Thai red curry soup (though if you ask me the authors should have demanded haggis). Sonic Youth, who rarely sound as if they’ve had time to tune their guitars, can apparently make a mean Italian wedding soup. And the Trachtenburg Family Slideshow Players (featuring a drummer who’s younger than some bottles of Scotch) have developed opinions on both salsa and homemade bread.

If the book has a fault, according to Hungry, it’s the authors’ unwavering focus on indie bands. Perhaps going for the arty and literate types was based on a hunch that they’d show the most promise in the kitchen. But when the recipes falter, it’s hard to muster much enthusiasm for three separate chili recipes by people you’ve never heard of. If, say, Elton John or David Byrne were wielding the spice rack, I might read out of sheer curiosity. The guys of Dirty Excuse, not so much.

And then, of course, there’s the danger of overingesting that hipster-band mainstay, irony. Exhibit A: a band called Japanther’s hot dog recipe, made with peanut butter and banana.

Still it’s an idea I wish I’d had first (such a good idea, it turns out, that this isn’t even the only book on the subject).

So if you could ask any band in the world, who would you ask, and what would you ask for? After brief discussion, here’s my top 10:

10. The Beatles’ “Honey Pie” (closely followed by marmalade skies)
9. The B-52s’ “Rock Lobster” bisque
8. Spinal Tap’s miniature luncheon-meat sandwiches
7. The Smiths’ recipe for veggie lasagna
6. Something weird by Cibo Matto – either the Sci-Fi Wasabi or the White Pepper Ice Cream
5. Whatever Bob Dylan served that time he had a job in the great north woods, working as a cook for a spell
4. Oasis’s mimosa (preferably non-supernova)
3. U2’s humble pie
2. Meat Loaf‘s meatloaf
1. Abba’s cheese fondue

The song might remain the same, but the list can go on and on – please add your own most-wanted recipes in the comments section!

A carpet of moss, courtesy of Flickr user Morning Glory

Possibly the world’s most ancient celebrity has now had his dinner described down to the very last fibrils of moss. Or mosses, to be exact. Scientists have found six species in the intestinal tract of Ötzi, the 5,200-year-old “iceman” who was discovered frozen into a glacier in the Italian Alps in 1991.

Even in mummy terms, 52 centuries is old. Ötzi is as old or older than the famous Egyptian mummies, despite having been preserved by little more than coincidence and cold weather. He was found half-encased in ice at 11,000 feet elevation, still dressed in grasses and furs and carrying an axe of nearly pure copper. This man was alive before bronze was invented.

His incredible degree of preservation has allowed scientists to follow Ötzi’s prehistoric lifestyle like a gang of paparazzi. The forensic techniques they’ve brought to bear hint at bizarre CSI storylines yet to be scripted. From bone details, pollen grains, DNA molecules, isotopes in his teeth, and an ominous arrowhead lodged in his shoulder, we know that Ötzi grew up about 35 miles south of where he died, at 46, probably herded sheep in the high country, was a better hiker than his contemporaries, got into a serious fight with some tribesmen, fled through forests of hornbeam, died from his wounds, and ultimately left no descendants in modern Europe.

As someone who is often at a loss when confronted by tracks in new-fallen snow, I just love to read about people who can see this kind of detail across five millennia.

And then of course there’s the part we’re interested in on this blog: the iceman’s food. From the new research, it looks like you won’t need to add mosses to your favorite Copper Age recipes. Mosses have nearly zero nutritive value, don’t taste of much, and are nearly universally ignored as people food. Ötzi probably consumed them incidentally. But how?

In those days before water filters, several species probably came from the water he drank. But two species are more tantalizing. One type was probably used to wrap food, as kind of an ancient sandwich baggie. Researchers found bits of it throughout Ötzi’s intestine; in the wild it forms mats on rocks, seemingly perfect for making wrapping material. The other species, a type of peat moss, is acidic enough to have been useful as a traditional medicinal compress to fight infections. Ötzi probably spent his last desperate hours clutching the moss to his arrow wound – and not bothering to scrub his hands clean when he ate.

The mosses are actually the last of the iceman’s gut contents to be analyzed by researchers – previous work had already divined the main ingredients of the man’s last two meals. The food included a primitive kind of wheat (possibly made into bread), plum-like fruits called sloes, two kinds of red meat (ibex and red deer), and copious amounts of charcoal indicating he’d cooked over open flame. Which means, I guess, that now we know what Ötzi’s answer to Amanda’s question would have been.