Oh Nuts: Bad Pine Nuts Leave Behind Bitter Taste For Weeks
Jul12

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. 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. 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 paper. 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. When the researchers analyzed both their 1H NMR and 13C NMR data sets with principal component analysis, they saw that all the P. armandii samples—not all of them positive for pine mouth—clustered on the negative end of the scatter plot. A negligible number...

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