It started with a conversation about popcorn. My husband and the neighbor share a love for it. But my husband has another gustatory indulgence, bacon. Combined with his tendency for wild exaggeration and his knack for persuasion, my husband convinced the neighbor that uniting the two foods occurred in kitchens routinely. “I pop it in bacon grease, doesn't everyone!” was what he told her.What exactly happens when fat hits the tongue? Rather, when it melts onto it, mixing with saliva, creeping its way into the furrows and between the taste buds. Is it the flavor, the texture or the ability of the lipid to carry smell, that tickles the mouth in such a way to warrant taking another bite and another and another?
Up until a couple of years ago, scientists would argue that our tongue likes to wallow in fat's creaminess, leaving flavor for sweet, salty, sour and savory (umami) receptors to sense. But in 2005, a protein lodged in the tips of taste cells (in mice) was found to recognize fat. The discovery suggests fat has its own flavor.
Each taste bud, containing 50 to 100 taste cells extend into tiny wispy structures, feelers, reaching into the world of the mouth. Taste receptors—proteins—are tucked into the cell like sausages baked in pastries. Slathered in saliva, they await their signal.
The protein described three years ago as the tongue's fat detector, ironically called FAT (standing for Fatty Acid Transporter) is thought to signal through nerve cells, telling the gut by way of the brain, that fat is on the way. But, the brain does more than to communicate with viscera. Neurotransmitters such as endorphins, released soon after fat intake, transmit feel good signals.
This burgeoning FAT research is lead by a group in France—a place where fat infused cuisine is emblematic. And the research team's latest results are the most mouth watering: that fat has “taste”. Monitoring the inside of mouse taste cells, the scientists noted a “taste” signature—a molecule that was released only when the cell was exposed to fat. They also established that a nerve bridging the mouth to the brain conveys this taste signal and associate a region in the brain involved in tasting. This distinction is notable. Until now, report after report states fat is flavorless. The authors conclude that “The gustatory pathway is involved in the oral perception of long chain fatty acids in the mouse.”But what about for humans. Without evidence that the FAT protein is present in my taste cells, I have to wonder if fat has real flavor? When a mouse eats triglycerides (found in animal fat) an enzyme in saliva breaks them down into fatty acids. This process, however, has not been described in people. And it hasn't been shown that the FAT protein is in our taste buds.
Inspired by the popcorn discussion, our neighbor went home and cooked two slices of bacon. She saved the fat and later that night fortified the vegetable oil she normally uses to make popcorn. She raved about the product well before she discovered my husbands lack of candor.
I have endured many popcorn experiments. Popcorn popped in coconut oil, in corn oil, popcorn scorched in butter, popped with sugar, bathed in butter, air popped, shaken on the stove top, popped in aluminum and stainless steal poppers. Bacon grease is the last pop stop.
The experience my neighbor reported included a combination of flavor and olfactory sensations that sounded exquisitely synergistic. Now it was time to do my own experiment and I couldn't have timed it better. Last night we had a house full of vegetarians (all with a well developed sense of humor). The potluck included: baked potatoes, grated cheese, green beans, rice, pasta with red sauce, bread, bruschetta and... bacon. After dinner, we gathered in the living room to watch surfing and Tuvan throat singing documentaries and to eat, lard popped pop corn.
Going into the experiment, I was skeptical. Especially since, our popping agent was not diluted with vegetable oil. I imagined a thick film would coat my tongue and the roof of my mouth. And projected that translucent sheen eventually transferring to the inner walls of my arteries to form a thick yellow/white layer. But I have to say, the palatability was indeed superb and surprisingly light. Salty, savory—satisfying, despite my bias. Handful after handful found their way to mouths and soon it was gone.
Now, I'm sure there are a few other reasons why this popcorn was particularly delicious. After all, it contains almost every other taste stimulator. Protein remnants surely activated savory receptors. Every bite was a miniature salt explosions. And the tongue's sweet sensors couldn't be silent as saliva induces breakdown of starchy corn. Oh, the aroma too. As my neighbor put it, “It's a real delicacy. Though, sprinkling it with cheddar cheese might even make it better.”
And so the popcorn conversation spurred not only my interest in what makes fat good but what makes the perfect bowl of popcorn. I'll have to keep you posted on the science behind the flavor of fat but I will tell you an excellent popcorn recipe that doesn't require lard:
2 Tablespoons grape seed oil
2 Tablespoons butter
Heat in a stainless steal popper with a turn paddle. Add
1/3 cup popcorn
D. Gaillard, F. Laugerette, N. Darcel, A. El-Yassimi, P. Passilly-Degrace, A. Hichami, N. A. Khan, J.-P. Montmayeur, P. Besnard (2007). The gustatory pathway is involved in CD36-mediated orosensory perception of long-chain fatty acids in the mouse The FASEB Journal, 22 (5), 1458-1468 DOI: 10.1096/fj.07-8415com
