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Category → Chemistry and Food

Oh Nuts: Bad Pine Nuts Leave Behind Bitter Taste For Weeks

This past weekend, I was on the hunt for some pine nuts. They’re not always easy to find in the grocery store, and they are almost always expensive. But I love them so—the delicious prize is always worth the aggravation of the search.

Credit: Flickr user Eating The Week

When I finally came upon the pine-nut container in a crowded aisle at the store, I checked to see where the small edible seeds were from. “India,” the container said. And I breathed a sigh of relief.

The reason for my nut-origin prejudice is a condition known as “pine mouth,” or “pine nut syndrome.” At a party earlier this year, a new acquaintance was delighting people clustered around her with what I thought sounded like a fantastical story of bad pine nuts from China inducing a bitter taste in people’s mouths for weeks after their ingestion.

In this case, though, I was wrong to poo-poo the tale. A paper from the Journal of Agricultural & Food Chemistry

recently came across the Newscripts desk in which researchers from Germany, Russia, and Belgium banded together to devise a way to sort good pine nuts from taste-altering bad ones. And most of the bad nuts happen to be from China.

Delicious, delicious pine nuts. Credit: Flickr user Culinary Cory

About one to three days after ingesting a bad pine nut, the victim develops a bitter, metallic taste in his or her mouth that lasts “for some days up to two weeks,” says Dirk W. Lachenmeier, the lead author of the JA&FC


Lachenmeier, who works at the Chemical & Veterinary Investigation Agency in Karlsruhe, Germany, says he got interested in pine nut syndrome when several nut samples, accompanied by consumer complaints, arrived at his institute. His agency is one of a series of state-run facilities in Germany that are the authorities on food control.

Initially, Lachenmeier and his team searched for a cause for pine mouth—a specific culprit compound. Unsuccessful, they instead devised a method based on NMR spectroscopy to weed out the naughty nuts. The researchers looked at 57 samples total, from China, Italy, Pakistan, Spain, Turkey, and the Mediterranean, and found in almost every situation where the nuts caused pine mouth that the samples had come from a species of pine tree called Pinus armandii. China happens to frequently harvest seeds from this nontraditional pine species. But Lachenmeier and team also found two other pine-mouth-inducing P. armandii samples, from Spain and the Mediterranean. Continue reading →

Label Blunders: Navigating the Ingredient Landscape

SeeArrOh ponders advertising trickery in a chemical world. SeeArrOh is a Ph.D. chemist working in industry.

This morning, I was reading over Carmen Drahl’s Storify collection of “chemical-free” discussions (#altchemicalfree) on Twitter. The recent backlash against the moniker has been covered extensively by ScienceGeist, RSCBlogs, and PLoS Speakeasy Science. After a brief chuckle, I went over to the sink to brush my teeth and happened to glance over at the mouthwash bottle. The top proudly proclaimed “Alcohol-Free!” in large green letters, so I naturally flipped it over: Propylene glycol, sorbitol, and menthol were listed among the ingredients. I understand the company should say “contains no ethanol,” but maybe someone should inform IUPAC that product packagers want to remix the chemical lexicon.

Mass marketing of consumer goods plays on human perception but not always on chemical intuition. Thus, companies will often use a trivial name for a compound to drive sales, without informing the consumer that the definitions don’t paint the whole picture. Take “sugar-free,” which commonly means a product made with no sucrose, or common table sugar. Biologists and chemists name sugars with the suffix “-ose,” which means that fructose, glucose, maltose, and a host of other substitute sweeteners still fall under the category of “sugar.” 

Ever see products that claim “No MSG”?  Check the label: It’s likely that they instead contain monopotassium glutamate, which generates the same umami taste but without the pesky sodium ion. Same for “low salt” foods that still taste salty, thanks to a variety of calcium and potassium substitutes—which themselves are salts!  “Fat-free” chips and baked goods still contain palmitates and stearates, and “100% juice” has vitamins and additives in quantities you wouldn’t see if you actually squeezed the oranges yourself.

Food producers aren’t solely to blame because the easy packaging half-truths extend to other products. “Nitrogen-enhanced” gasoline, which admittedly contains nitrogen-derived detergents, probably hasn’t had actual N2 bubbled into it.  Similarly, look for pet sprays and bleaches with “oxygen- power” derived, most likely, from hydrogen peroxide.

So read those labels carefully.  Anything that sounds too chemically convenient should be taken with a grain of, well, sodium chloride.

Fun With Food Analysis At #ACSAnaheim

If you’ve been in grad school or worked in a lab, you’ve been there: sitting around, waiting for your reaction or experiment to do its thing, bored, listless. Then your eye lights on a can of Sprite. Then the pH meter. Then back to the Sprite. The wheels start turning, and before you know it, you’re testing all of your labmates’ drinks and making bar charts.

Or maybe that’s just me.

For Christopher J. Hudalla, it’s all in a day’s work. Hudalla, a senior scientist at Waters Corp., in Milford, Mass., gave a presentation today at the ACS national meeting in Anaheim about the development of a chromatographic stationary phase for separating a battery of simple sugars. After putting his “bridged ethyl hybrid” phase through the standard paces, demonstrating that it indeed separated a mixture of fructose, glucose, sucrose, lactose, and maltose quite nicely, Hudalla got serious.

Hudalla's lunch tests. Credit: Chris Hudalla/Waters

He wanted to throw everything he could think of at the stationary phase, which is proprietary but has a silane on one end and an amide on the other, to test just how robust it actually is. So he began taking samples of his coworkers’ lunches, he said. Everyday, there was a new food item to test. It became a ritual—a lunchtime club—and Hudalla amassed a “large stack of chromatograms of some very strange things,” he told me. “My colleagues wondered why I had an analysis for Asian dipping sauce.”

Then came the beer. Why not test the components of beer during brewing? Hudalla followed the sugar components of a beer mix during mashing, a process in which malt enzymes break down grain starches into sugars (typically maltose), and during fermentation, when the maltose is fermented by yeast to produce alcohol.

Hudalla's "frivolous" beer tests. Credit: Chris Hudalla/Waters

Turns out that the stationary phase does what it’s supposed to: Hudalla didn’t find any products for which it couldn’t separate those simple sugars cleanly. And although some of the tests seemed frivolous at the time, he said, a major beer manufacturer has since expressed interest in the method.

Got any food and/or strange product tests to share that you’ve carried out in the lab? Post them here.

Frito-Lay’s All-Natural Chips And Chemical Stereotypes

Et tu, Frito-Lay? (Shutterstock)

The Wall Street Journal had a piece yesterday on companies’ moves to create all-natural junk foods that still have that special junk food taste. Newscripts readers will probably guess how the story goes- take out ‘chemicals’ and replace them with ‘natural’ ingredients. Well, that’s not exactly how it plays out. The story acknowledges that some junk food ingredients that sound ‘unnatural’ are quite the opposite. It also notes that the Food and Drug Administration hasn’t come up with a formal definition for ‘natural’, and that many natural foods are processed. I won’t bother discussing why an all-natural diet that consists of potato chips and soda is not the healthiest. But I will throw a choice section of the article your way- about ingredients Frito-Lay has chosen to replace in its potato chips.

Some ingredients—like ascorbic acid, a color stabilizer—sound artificial but are not. Frito-Lay is eliminating those from some of its snacks, too. Ascorbic acid has been replaced with rosemary, another natural antioxidant.

Frito-Lay is slapping “all natural” stamps on its packaging as it rolls out the reformulated snacks—part of the company’s largest-ever marketing campaign to drive home that many of its products are made from regular ingredients.

Why the change, Frito-Lay?

More reading: Well-written guidance on navigating words like “chemical”, “natural”, and “organic”, by Sharon at I Can Has Science.

Dark-Colored Sodas May Have Toxic Backwash, Or Not

The Center for Science in the Public Interest (CSPI) has made a claim that “caramel coloring” used to improve the eye appeal of colas and other dark-colored soft drinks contains the carcinogenic by-products 2-methylimidazole and 4-methylimidazole (shown) and thus might be a cause of thousands of cancers in the U.S. The nonprofit consumer advocacy organization made its announcement via a regulatory petition filed with the Food & Drug Administration on Feb. 16.


Besides being used in colas, the artificial coloring, which can range from yellowish to black, is used in some baked goods, precooked meats, soy and Worcestershire sauces, chocolate-flavored products, and even whiskey and beer. It’s typically made by pyrolyzing sugar with the aid of ammonium and/or sulfite compounds, a process that forms many derivative chemicals. This browning process is similar to, but distinct from, the Maillard reaction between a sugar and an amino acid. CSPI wants FDA to revoke regulations allowing the types of caramel coloring made using ammonium compounds, which contain the imidazoles.

“Carcinogenic colorings have no place in the food supply, especially considering that their only function is a cosmetic one,” CSPI Executive Director Michael F. Jacobson said when announcing the petition. CSPI is invoking the Delaney Clause, an amendment to the Food, Drugs, & Cosmetic Act of 1938, to state that FDA is obligated to ban caramel coloring–the clause stipulates that FDA “shall not approve for use in food any chemical additive found to induce cancer in man, or, after tests, found to induce cancer in animals.”

The issue of the toxicity or nontoxicity and possible regulatory control of the imidazole compounds has been bouncing around for a few years. CSPI based its petition on a pair of 2007 studies (1 and 2) published by the National Toxicology Program (NTP), a unit of the National Institute of Environmental Health Sciences. The studies conclude that 2- and 4-methylimidazole, compounds known to be in cigarette smoke, caused cancer in rats and mice. But NTP has not listed the imidazole compounds as being carcinogenic.

Continue reading →

The Chemistry of Stadium Foods

Here at the ACS meeting in Boston, Newscripts was part of an elite group of reporters treated to a quick lesson in popcorn, ballpark hot dogs, and beer before a Red Sox game at Fenway Park. “The Chemistry of Stadium Food,” is part of an ongoing series of events on food chemistry at national meetings hosted by the ACS Office of Public Affairs.

Fenway Park and the Green Monster. Credit: Boston Visitors & Convention Bureau

The Boston event was held at Jerry Remy’s Sports Bar & Grill adjacent to the historic ballpark. Remy is the popular announcer for the Red Sox. The tutorial featured two leading food chemists: Sara J. Risch, founder of the food-consulting firm Science by Design, and Shirley Corriher, a cookbook author whose latest work is “Bakewise: The Hows and Whys of Successful Baking.” Risch and Corriher previously teamed up at the ACS meeting in Washington, D.C., to talk about the art of barbeque and at the meeting in San Francisco to talk about the sour in sourdough bread.

First up to bat in Boston, Risch gave a short warning about food safety in ballparks, given that a recent survey of ballparks found that most food-service vendors had poor health and safety ratings. Ballpark food service staffs tend to be minimum-wage workers or volunteers without training, Risch said. If the owners and managers of food kiosks aren’t diligent, there can be some public health issues with spoiled food—food could be undercooked, not properly refrigerated, or kept at an unsafe temperature for too long after it has been prepared.

For example, Risch says she would probably avoid sushi, oysters, or any raw foods in a ballpark—you can find just about anything on a ballpark menu these days, from iced coffee to hummus to veggie dogs. Fried foods are pretty safe, she noted, because they have been cooked at a high temperature, although the extra fat is a tradeoff. But you only live once. Continue reading →

Alcohol and Solvency

While the Newscripts gang has been known to indulge in a cocktail or two, we doubt that even our penchant for pricey vodka could rack up a liquor store bill in excess of $400,000. But not John Runowicz, NYU’s former chemistry department budget director. Or at least that’s what NYU thought he was spending at a local liquor store. Over the course of five years Runowicz submitted 13,000 receipts from the same liquor store to petty cash. He had pilfered $409,000 (that’s what I call solvent!) before his repeat receipts were spotted by a curious courier. Today, as the New York Daily News reports, he was sentenced to one to three years in prison.

So, chemistry students, any way your department could credibly spend over $80,000 a year on booze?

Speaking of drinking, we read an interesting article on alcohol proof this week in the Washington Post. Proof, as you may recall, is simply the percent of alcohol times two (math even an organic chemist can do). Since alcohol is such a good solvent for flavor compounds, proof has been on the rise in spirits in recent years so that bartenders can produce potent potables that pop with flavor. Even alcohol levels in wine have been creeping up to deliver a bigger burst of fruit flavor.

Chemist and absinthe enthusiast Ted Breaux even weighs in with an explanation of why the green fairy boasts such a high alcohol content–136 proof. “You have to bottle it at high proof because of the herbs. You want clarity, and if the proof isn’t high enough, the compounds will deteriorate. The spirit becomes hazy with sediment, and it looks awful,” he tells the Post.

Finally, in a tipple trifecta, a former Amgen chemist is distilling his own whiskey in the unlikely state of Utah, reports the Thousand Oaks Acorn. I got a good giggle out of this amended quote from chemist-turned-whiskey-maker David Perkins: “Making whiskey is a lot more fun than (pharmaceutical) drugs, as you get to taste the results as well as the in-between experiments.”

What’s in Your McNugget?

It’s no secret that McDonald’s sells different fast food products in different countries. For example, in Korea, you can get the Bulgogi Burger (pork patty in a bulgogi marinade) and a McBingSoo (Korean shaved ice) to wash it down; in El Salvador, French fries are made out of yuca rather than potatoes; and in Egypt, you can order the McFalafel sandwich and Egyptian cookies.

You may be surprised, however, to find out that even the same product sold in different countries can contain different ingredients. A recent article in CNN.com pointed out that Chicken McNuggets sold in the U.S. contain more calories and saturated fat than McNuggets in Great Britain. What’s more, American McNuggets also contain the preservative tertiary butylhydroquinone (tBHQ) and the anti-foaming agent dimethylpolysiloxane whereas British McNuggests do not.

In the article, Marion Nestle, a New York University professor and author of “What to eat,” recommended that readers avoid foods containing ingredients they can’t pronounce.

Is this really sound advice?