We"ve all competent it. You walk right into your kitchen or your office breakroom, and also the smell assails you: savory, buttery, toasty. Someone"s been microwaving popcorn. Yum — or ick, relying on your sensitivity.

You are watching: Why does burnt popcorn smell so bad


Google searcs for the smell of microwave popcorn bring about threads that mention all kinds of odors, from buttery heaven to vomit to urine. (More accurately, it smells like a bearcat"s butt, researchers say.)

Love it or hate it, the smell of microwave popcorn is distinct. So, what"s the chemical behind the aroma? In many situations, it"s among a number of artificial flavorings known for their oily, buttery vibe. These flavorings have periodically showed up in the news, mentioned as health and wellness dangers, yet there isn"t proof that they hurt the casual popcorn-popper; they rather pose a danger, according to the National Institute for Occupational Safety and Health (NIOSH), to workers who inhale them in big quantities at framework wright here microwave popcorn is made. <9 Snack Foods: Healthy or Not?>


Hidden damage

One of the a lot of common flavorings in popcorn is a compound dubbed diacetyl. In foods items prefer butter and also sour cream, diacetyl occurs normally as a byproduct of fermentation, and it imcomponents that creamy, buttery flavor so preferred in these foodstuffs. For its use as a food additive, diacetyl is made by removing hydrogen from another substance, 2,3-butanediol.


Diacetyl became a subject of health and wellness involves in the early 2000s, once researchers publimelted findings from a microwave popcorn plantwright here eight former workers came down through severe obstructive lung disease. Diacetyl was among the the majority of significant contaminants in the plant"s air. That finding led to an selection of animal and also epidemiological studies that uncovered that, sure sufficient, the substance can damages the cells lining the lungs and trachea. The resulting condition is called obliterative bronchiolitis, and it produces inflammation and also scarring that can be negative enough to require a lung transplant, according to the Centers for Disease Control and also Prevention.


In 2007, a number of popcorn manufacturers — including ConAgra Foods Inc., General Mills Inc. and also the American Pop Corn Company type of — shelp they were phasing diacetyl out of their commodities, according to Associated Press reports at the time. However before, a 2016 examine in the journal Toxicologic Pathologyutilizing rats uncovered that the replacement chemicals they offered — 2,3-pentanedione and also 2,3-hexanedione — can likewise reason lung damages.

Tright here is no evidence that these compounds cause damages for human being popping popcorn prior to movie night at home, yet, the researchers composed.

Both diacetyl and pentanedione are reactive compounds, and their retask comes from the very same energetic chemical team, referred to as a dicarbonyl team, sassist Ann Hubbs, a researcher at NIOSH who has studied the substances. The just distinction in between the 2 compounds, Hubbs told Live Science, is that diacetyl is a four-carbon compound, while pentanedione boasts five carbon molecules. When these compounds come into call with the lining of the respiratory system, they damages proteins in the airways.


The chemicals react specifically easily with an amino acid (a protein building block) dubbed arginine, Hubbs shelp. The outcome of such reactions, periodically recognized as "popcorn lung," is irreversible damage to the tiny alveoli wright here air exchange occurs in the lungs.

What"s that smell?

Microwave popcorn"s smell is distinctive, however you can catch a whiff of it in other odd places. The binturong, or bearcat, a Southeastern Eastern mammal, is famed — as far as Southeast Eastern mammals go — for smelling like buttered popcorn. That"s because an additional compound that offers microwave popcorn its smell additionally appears in the urine of the binturong.

A 2016 research in the journal The Science of Nature found that binturong urine is chock-full of a compound referred to as 2-acetyl-1-pyrroline. This substance forms throughout the Maillard reaction, or the browning reaction that occurs once sugars or amino acids are heated. (Like crusty bread? Thank the Maillard reaction.)

In popcorn, 2-acetyl-1-pyrroline provides off a toasted smell as the sugars in the kernels heat. This compound is likewise discovered in foods items like white bread and jasmine rice. The binturong or bearcat supplies the substance for scent-noting.

The Duke researchers that discovered the compound in binturong pee also uncovered that it was one of the few compounds in the animals" urine that smelled stronger with time, probably explaining why your microwave reeks for days after movie night. There"s even at least one blog through tips for rerelocating the popcorn stink from your microwave.

(Binturongs most likely create the compound in collaboration with microbes living near their urinary tract or anal glands, according to the Battle Each Other researchers.)

If your own pee starts smelling prefer popcorn, though, you might want to pay attention. According to Healthline, a health indevelopment website composed by doctors, popcorn-smelling pee can be a harmmuch less side impact of eating or drinking somepoint that has a large amount of compounds dubbed ketones (diacetyl is a ketone, but various other types of ketones are uncovered in all sorts of foods). Or the smell might be a authorize that your body is excreting as well many kind of ketones on its very own, a feasible symptom of diabetes.

Initial short article on Live Science.

See more: What Is The Function Of The Corpora Quadrigemina? Name The Functions Associated With It


*

Stephanie Pappas is a contributing writer for Live Science. She covers the world of huguy and also pet actions, and paleontology and also other science topics. Stephanie has a Bachelor of Arts in psychology from the University of South Carolina and also a graduate certificate in science communication from the College of The golden state, Santa Cruz. She has actually ducked under a glacier in Switzerland also and poked warm lava with a stick in Hawaii. Stephanie hails from East Tennesview, the international center for salamander diversity. Follow Stephanie on Google+.