November 27, 2013
Just In Time For Thanksgiving Comes Turkey Science
Lee Rannals for redOrbit.com - Your Universe Online
Each Thanksgiving, 46 million turkeys are consumed by 88 percent of Americans, but what do we actually know about the bird that graces our table each year? redOrbit has dug up some facts about the delectable birds to help throw a little knowledge down at the dinner table this year to impress the in-laws.
The National Bird
As most everyone knows, the Bald Eagle is America’s national bird. However, Benjamin Franklin had a poor outlook on the Bald Eagle and instead wanted the turkey to represent our country. Franklin wrote the following letter to his daughter Sarah Bache on January 26, 1784 about the Bald Eagle versus a turkey:
“Others object to the Bald Eagle, as looking too much like a Dindon, or Turkey. For my own part I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk [Osprey]; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him."
"With all this Injustice, he is never in good case but like those among men who live by sharping and robbing he is generally poor and often very lousy. Besides he is a rank coward: The little King Bird, not bigger than a Sparrow, attacks him boldly and drives him out of the district. He is therefore by no means a proper emblem for the brave and honest Cincinnati of America who have driven all the King Birds from our country... I am on this account not displeased that the figure is not known as a Bald Eagle, but looks more like a Turkey. For in Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America... He is besides, though a little vain and silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his farm yard with a red coat on,” his letter concluded.
Physics of Cooking Turkey
While it seems unlikely we will ever see the turkey become our national symbol, it doesn't mean we cannot celebrate this bird at least one day out of the year. And for those 88 percent of Americans who plan to have turkey for Thanksgiving this year, the next bit of information may come in rather handy.
Cooking turkey has become almost an art around Thanksgiving, but science is what helps make the bird delicious each year. As the turkey is cooked, muscle fibers contract until they break up at around 180 degrees Fahrenheit. The bonds within the molecules begin to break down, which causes proteins to unravel and the dense muscle meat to become more tender.
The bird’s collagen breaks down into softer gelatin molecules as it unwinds and as proteins coagulate the dryness of a turkey begins to ensue, which is what happens to overcooked turkey.
Pief Panofsky, a former director at the Stanford Linear Accelerator Center, developed an equation to determine a more precise cooking time of a turkey. Traditional cooking guidelines once suggested turkey be cooked for 30 minutes per pound, but Panofsky said the time a turkey should be cooked is not a linear equation. Instead, he developed an equation based on the ratio between the surface area and mass of a turkey.
In the equation, t = W^(2/3)/1.5, "t" is the cooking time in hours and "W" equals the weight of the turkey in pounds. The 1.5 constant was determined empirically. Assuming people follow this equation, Pief suggests turkeys should be cooked at 324 degrees Fahrenheit.
A Thanksgiving Nap
Now that you got your bird cooked to perfection, it is time to enjoy a nice holiday meal with all your dinner guests. Just don't feel bad that afterward everyone is too tired to help put away the food and clean the dishes. But why would they be tired?
One of the most commonly debated myths surrounding turkeys is how consuming the birds’ meat makes you sleepy. The reason this topic can be hotly debated amongst family and peers is because it is kind of both true and untrue.
Turkey meat contains an amino acid called tryptophan that the body uses to make serotonin, which is a neurotransmitter that helps regulate sleep. In theory, this amino acid should make you sleepy but all meat contains similar levels of tryptophan, and a few exceptions like shellfish contain even higher levels.
So, while tryptophan does in fact make you sleepy it is not the sole cause of the Thanksgiving power nap. A mixture of meat and carbohydrates is actually what helps set up the tryptophan to do its after-dinner dirty work. Carbohydrates stimulate the release of insulin, which triggers the uptake of most amino acids from the blood stream into the muscles, except tryptophan. After all the other amino acids are swept away in the blood stream, tryptophan has no more competition, enabling it to make its way up to the brain to produce serotonin.
Now that the dinner facts have been taken care of, we can move on to some other perhaps equally as interesting facts about our feathered friends.
One common misconception is that turkeys are unable to fly, but this understanding is as false as serving tofu and calling it meat at the Thanksgiving table. The only truth to this statement is when talking about domesticated turkeys, which have been bred to be so plump that they are unable to get off the ground.
Wild turkeys are not only able to fly, they can actually fly short distances at speeds of up to 55 miles per hour. However, these birds do not soar too far from the ground, which helps to keep them close to food sources like grass, seeds, acorns, nuts, berries and small insects.
It is this attribute that allows turkeys to hide away in trees when they sleep at night. Scientists say turkeys sleep up in trees to help keep away from predators like coyotes and foxes. When the turkeys wake up in the morning they make a call to see whether or not their comrades made it through the night, or maybe had become someone’s Thanksgiving dish.
Random Turkey Facts
While some patrons of the dinner table may not appreciate the physics of cooking a turkey or the science behind the sleepiness, they may enjoy learning a few facts that may or may not be easier to comprehend.
For example, researchers at the University of Illinois say the turkey lived almost 10 million years ago and the largest turkey ever raised on a farm was 86 pounds.
When a turkey becomes frightened, agitated or excited it is able to change the color of its head and neck from pink to red, white or blue. During mating season, male turkeys can change the color of its “wattle” to scarlet to reflect his elevated sex hormone levels.
Female turkeys are actually unable to gobble, instead they make chirp and click sounds. Male turkeys each have their own unique gobbling techniques and when combined with strutting the bird is just a couple moves away from finding a proper mate.
Turkeys also have periscopic vision, allowing them to see objects that are not in direct line of sight. Not only can turkeys see movement almost 100 yards away, they can also turn their head from left to right to get a full 360-degree field of view.
Finally, a turkey’s gizzard actually contains tiny stones that the bird has picked up while scouring the ground for food. These stones, known as gastroliths, help to breakdown food for digestion because turkeys lack teeth to do so. When a turkey eats, food goes into the glandular stomach where it is broken down by gastric juices. After this, the food enters the gizzard where it is dissolved through grinding against the gastroliths before moving back into the glandular stomach for further digestion.
In 2011, 736 million pounds of turkey were consumed in the United States. Although it may seem like Americans eating this much turkey could lead to the native bird’s extinction, turkey production has actually increased 110 percent since 1970 while consumption has increased 104 percent.