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Marvelous milk

1 Dec

Cow suckling her calf

Most of my news articles don’t have a back story. But my most recent chemistry story combined food, molecules, animals. . .  and a little bit of family.

Dairy runs in my family. My grandfather ran a small dairy for more than 30 years, in and around his day job. My father has worked in dairy science, as a university professor, but mostly working in Extension, working with dairy farmers and tools that keep track of milk data and production. My uncle, a large animal veterinarian, does embryo transfers in cattle.

So, when an editor approaches me with a milk story, I’m game.

Though I knew that milk provides a way for moms to provide antibodies to babies, I’m intrigued by the possibility that there are a mixture of enzymes that may both activate milk proteins within the stomach and then shield them from being shredded into amino acids. This chemical and biological marvel mixes fats, proteins, and sugars and even whole cells. Researchers now have a pretty good picture of what’s in there, but plenty of work remains to figure out how it all works together.

Image Credit: Wikimedia Commons

The kitchen laboratory

21 Oct

Molecular gastronomy in action: strawberry ravioli on a spoon before being dropped into a liquid nitrogen bath. Credit: iStockphoto/Thomas_EyeDesign

These days the kitchen is my chemistry lab, and if I were back in college I’d probably be one of the students beating down the door to get in to a cooking science class like this one at Harvard.

Despite my experience with chemical gadgets, the wildest item in my kitchen is a food processor. Watching what molecular gastronomy folks cook up next soothes my strange secret longing for a rotary evaporator and a supply of liquid nitrogen. So last month, I headed over to the Experimental Cuisine Collective meeting to find out about a chemical kitchen topic, flavor pairings.

Bernard Larousse started with a fascinating side note about the partnerships that he and his colleagues are building between chefs and scientists with the Flemish Primitives. Chefs used ultrasound to make stock, but my favorite funky food gadget had to be the fluidic plate (my term, not his). Researchers developed plates that work like microfluidic chips (see earlier post), electrical circuits within the plates allow chefs to deliver water droplets to the food at a defined point in time. Sure, this isn’t really practical at home (Yes, I want one). But this plate has the right mix of posh and geeky food style.

But back to the flavor chemistry. Eighty percent of taste comes from the sense of smell, as most of us notice when we have a cold and all food tastes like cardboard. But what makes two flavors work together? Researchers have analyzed the flavor components and compared them. A good match is all about having a similar mixture of component flavor compounds. This doesn’t take into account other issues such as texture. If you have two foods where the flavors don’t overlap, you can bridge between them with a food with flavor components that overlap between the other two: cheese and vanilla don’t match, but they work fine if you add coffee.

The website maps these chemical relationships on a wheel. Like foods are grouped together on branches, and the distance from the central food indicates how well it matches. Take this one for strawberries: I don’t think I every would have matched them with mussels. Not only can you make new matches, you can also figure out how to replace a flavor with other components with related flavor profiles.

That last piece seems to be particularly useful for vegetarian foodies, who’d like to replicate the robust flavor of meat. Larousse also points out that it can be a way for locavores to replace non-local ingredients. Replacing an ingredient like citrus with other natural ingredients still seems a bit more like a science project at this point– something that molecular gastronomers might try for fun. Ultimately, it’s probably easier for most of us to go buy an orange.

A Mother’s Day Torte

9 May

Sachertorte from the Hotel Sacher, Vienna. Copyright © 2005 David Monniaux

My mother will get the joke. About 10 years ago, after a trip to Europe when my mother lost her luggage, I bet her a slice of decadent European cake that she’d get the suitcase back. She did.

Though the stars haven’t aligned so that I can get my cake (in Europe, of course!), this slice is my way of wishing all mothers a very happy day.

Seaweed, sushi and science

17 Dec
Sushi!

iStockphoto/ShyMan

I prefer my seaweed applewood smoked. However, truthfully, before yesterday, I’m not sure I could have told you whether I liked seaweed, smoked or otherwise.

I do like sushi, but the seaweed within a maki roll has always seemed more functional than flavorful– a necessary material to keep the whole thing held together.

But when I heard about yesterday’s Experimental Cuisine Collective meeting– “The Science of Sushi and Seaweed”– I couldn’t resist. The speaker’s day job is as a biophysicist at a Danish university, and he haunts sushi restaurants (and even writes a book) in his spare time. Perfect.

And so I spent yesterday afternoon at a sushi science talk and algae tasting. Seaweeds are algae after all, not plants. So though many algae synthesize food from the sun, unlike plants, seaweeds are complexes of single cells. Plants are interdependent multicellular organisms– seaweed are communities of independent operators.

Ole Mouritsen talked in a lovely cultural and scientific hodgepodge– part cultural history and part science. The flavors of sushi– the sweetness of the rice, the sour from the vinegar– date back to old methods for preserving fish. Though no longer necessary, those lingering elements of taste are part of the sushi experience. A tidbit about wasabi– though it may be fiery– its punch comes from isothiocyanates (funky molecular structures that have carbon, nitrogen and sulfur lined up next to each other). But unlike other molecules that set our taste buds on fire (capsaicin in chili peppers, for example), isothiocyanates are water soluble. That’s why you can actually cleanse your palate pretty easily if you get a little too much of the evil green stuff.

But back to the seaweed. I’m definitely not ready to become an algaetarian, but seaweed definitely makes an interesting, sometimes pungent garnish. Nori– the ubiquitous sushi wrapping– is actually paper-like, easily torn. But when wrapped around sushi rice, it quickly absorbs water and the complex sugars become gummy. The Japanese annually fete Kathleen Mary Drew-Baker, the British botanist who figured out how to culture this particular algae.

Oboro kombu looks a little like vacuum cleaner lint and melts in your mouth like umami cotton candy. And then there’s the dulse– dark red, tangy, particularly the almost bacony applewood-smoked version. Don’t forget to sniff first.

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MotW: Happy T(ryptophan)-day!

26 Nov
Tryptophan, via Wikimedia Commons

tryptophan structure via Wikimedia Commons

Though the tryptophan rush from turkey is more hype than reality, Thanksgiving is the perfect time to put up the most structurally complex of the amino acids, tryptophan.

The body uses it to make serotonin, and biochemists use its absorbance of ultraviolet light to determine concentrations of proteins in their samples.

Today I’m thinking that it’s much more esthetically interesting than most of its amino-acid pals, at least the naturally-occurring ones.

Happy Thanksgiving!

Pop goes the antioxidants

21 Aug
fresh popped kernels courtesy of my kitchen

popped kernels fresh from my kitchen

Summer’s distracted me from blogging, but I just returned from the American Chemical Society meeting in Washington, DC. That meeting is a huge mishmash for me– a combination of catching up with former chemistry colleagues, meeting up with current writing colleagues, and getting myself back up to speed on what’s new with molecules.

Though it’s a small story in the broader sense of the ACS meeting, as a popcorn fan, I can’t help but be excited that my favorite salty snack– popcorn– also packs the highest per-gram punch of polyphenols, a class of antioxidants. Before anyone goes crazy, no, we shouldn’t all switch to a popcorn diet, particularly one that’s covered in butter, real or artificial.

Fortunately, I’m an old-fashioned gal when it comes to my kernels. I like them popped fresh in a little oil on a stove, just like Mom made before we had a microwave. Some of my most vivid memories of childhood road trips include riding down either I-95 or I-10 and the tug-of-war with my sister over who got to hold the large Charles’ Chips tin containing fluffy, crunchy saltiness that Mom had popped before we left home.

popcorn on the stove, just like Mom used to make

popcorn on the stove, just like Mom used to make

Back to the science, though– the popcorn was part of a larger study by Joe Vinson and his colleagues at the University of Scranton looking at antioxidants in whole grains. Like other plant-derived foods, whole grains have antioxidants and those chemicals could be part of the reason that these foods are healthy. Not a particularly new idea, I’ll admit. But as I’m crunching on a fresh pot of snack food, I don’t mind feeling just a little less guilty.

Molecule of the Week: Water

6 Jun
Rippling water drop, copyright iStockphoto.com/deliormanli

Rippling water drop, copyright iStockphoto.com/deliormanli

It’s been a rainy week in New York City, and my office next to our front porch and my container garden has me thinking about that ubiquitous wetness. It’s been soaking my plants, and after a quick errand on Friday afternoon, its dampness lurked for hours on the hem of my jeans.

It’s easy to take the wonder of water for granted because it’s everywhere, but its physical properties are anything but ordinary. Almost all solids of any substance are more dense than their liquid counterparts. But if ice were more dense than liquid water, ice cubes wouldn’t float in cool drinks on a summer day. Ice wouldn’t freeze at the tops of cold lakes (no ice skating), and polar ice caps would be more like suboceanic ice cushions. If water were a normal liquid, the Earth would look really weird.

Water molecule, via Wikipedia/Booyabazooka

Water molecule, via Wikipedia/Booyabazooka

The molecule itself is bent, lending hexagonal elegance to snowflakes. In a liquid the molecules glom to each other, not quite like superglue. But that watched pot (that seemingly never boils) needs lots of energy to release water into steam.

For those of us who’ve built molecules for a living, water is often our enemy, something that can get in the way and keep the right components from getting together. But Nature incorporates water beautifully, using the molecule as a structural tool and as a critical player in the reactions that make life work. Forced to take some tricks from Nature in my own graduate work (my highly charged molecules wouldn’t dissolve in any other solvent), working in water was like learning a related foreign language. I learned some basic grammar and vocabulary, but fluency of water chemistry is a challenge beyond the synthetic lab. By Nature’s standards, I was, perhaps, third rate.

I missed the AMNH’s exhibit on Water when it was in NYC (but I think it’s still touring, check your local science museum). As climates change, ice melts, sea levels rise, more intense storms brew in the oceans, water sits at the heart of the environmental challenge. According to the World Health Organization, as of 2002, nearly 20 percent of the world’s population didn’t have access to healthy, sanitized drinking water supplies.

Three atoms hooked together connect to the inner workings of life, health, the environment and public policy.

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Molecule of the Week: Vitamin D

30 May
Structure of Vitamin D by Sbrools via Wikipedia

Structure of Vitamin D by Sbrools via Wikipedia

Over the last several months I’ve gotten press releases just about every week about Vitamin D, usually talking about studies that show health problems connected to Vitamin D deficiencies. A lot of this discussion about “the optimal dose” of Vitamin D is still under debate, though. The main problem is that it is possible to get too much. Stay tuned because hopefully scientists will hammer out more definitive answers to this question soon.

In the meantime, though, the biochemistry of Vitamin D is pretty unusual, particularly when you compare it with other molecules that we call vitamins. Vitamin D actually functions as a hormone, a chemical messenger within the body. It’s particularly important for helping the body use calcium to build bone. 

However, Vitamin D production in our bodies depends on sunlight. We need UV light from to transform a molecule that looks a lot like cholesterol (a steroid molecule like testosterone, which I guestblogged about this week) into the Vitamin D that we need. We can store extra in fat deposits and many animal fats are a dietary source of Vitamin D.

From the number of studies that indicate Vitamin D deficiencies, my guess is that most people probably are lacking in Vitamin D even though it’s fortified in milk and found in animal fats. And even  natural production can vary a lot. Lighter skinned people tend to make more than darker skinned people. Based on where you live, how much time you spend outdoors, your genes and your age, your production will vary, too. On top of that, you don’t want to expose yourself to so much sun that you’re putting yourself at risk for skin cancer.

But Vitamin D is also a fat-soluble vitamin, which means that the body has a hard time getting rid of it if you make too much. Taking too much of a water-soluble vitamin, such as Vitamin C, isn’t usually a problem. Any extra will just get flushed out with your urine. But too much Vitamin D buildup in the wrong place can lead to calcium deposits.

So, I’ll be interested in what the experts decide is the optimal daily intake and how many health issues might (or might not) be related to levels of Vitamin D.

Summer is (almost) here

25 May
Memorial Day weekend in NY Harbor

Memorial Day weekend in NY Harbor

Fleeting moments between spring and summer are magic in my little corner of NY harbor. Bikes and rollerblades speed by– walkers, joggers, and marathoners-in-training drink in the cool breeze laced with sweetness (honeysuckle?). And the hardy fishermen (with an occasional woman) cluster in cultural pockets, speaking Chinese, Spanish, or Brooklyn-drenched English.

big fish

big fish

At another fisherman’s pocket, we found this catch-of-the-day, still gasping for breath. The anglers didn’t understand enough English to identify it to another passerby (probably 3 feet long– a striped bass– one of those fish that you actually can eat from NY harbor, my husband noted.).

By dusk we’d moved back inland stopping for dinner in our local diner, barely making a dent in the mounds of pot roast and the Greek combo.

Long walk + leftovers = holiday weekend

The pull of the urban garden

24 May

Although I now consider myself a urban gal and not necessarily a green thumb, my agrarian roots continue to tug on me. Last summer, I gave in to the gardening urge and our front porch erupted in  a jungle of herbs and tomatoes– tasty grape ones and some marginal Early Girls– they worked for gazpacho, but not much else.

one of my 2008 tomatoes "the butt"

one of my 2008 tomatoes "the butt"

I don’t think there are gardening genes per se, but if they did exist, I’d have them, even if they didn’t come accompanied by any particular skill. My mother’s sister still lives on the land in Virginia that my grandfather farmed for decades and raises most of her own vegetables in a large garden plot. The other side of my family has a strong streak of cattle farming.

Summer 2009 garden, first plants

Summer 2009 garden, first plants

Eating locally and raising one’s own food has become popular again, in part for environmental reasons, for health reasons, and, in some cases, it’s even economically more practical. I can’t fairly trace my own urges to grand principles such as saving the planet or avoiding pesticides, though those are nice perks. Honestly, it’s just satisfying deep down to watch plants grow and feel that tangible goal– the sweetness of a tomato as it bursts in my mouth or the added zest that my herbs added to a dish I just cooked.

Now that it’s Memorial Day weekend, I’m starting round 2 of my urban gardening experiments– the grape tomatoes are back along with Ramapos– the Jersey tomato. Now, if I can just manage to wait until July to see how it all turns out. . . .

2009 Ramapo tomato plants

2009 Ramapo tomato plants