And finally, the turkey (and about that tryptophan)
We already know that the Maillard Reaction browns and flavors the
turkey. As for another trendy way to improve flavor, brining,
chemistry is a key factor in its effectiveness, specifically osmosis.
The brining fluid contains many spices, sugar and crucially for this
discussion, lots of salt. Osmosis goes into effect, trying to create
an equilibrium amid the floating salt ions by initially sucking the
water out of the turkey, VandenPlas said.
This reaction explains why you can't shortcut the brining process,
she said. If you fail to brine it long enough, you end up with a dry
and salty turkey. But if you brine it for at least eight hours,
eventually through osmosis equilibrium is achieved and water returns
to the turkey, making it moist and flavorful.
But don't blame the turkey, specifically the tryptophan, for
post-dinner sleepiness, she said. In theory, the amino acid creates a
reaction that eventually leads to the production of melatonin, a
chemical that makes you sleepy.
In reality, however, tryptophan is one of many amino acids competing
for passage to the blood-brain barrier after the meal, and ultimately
doesn't doesn't get there in a high enough concentration to affect
sleepiness, VandenPlas said. Also of note: Tryptophan is in a wide
variety of foods, including other meats, eggs and cheese, not just turkey.
What is more likely the culprit for post-dinner nap time? The
potatoes, and stuffing, and rolls, and pie, and the many other
carbohydrates consumed with this meal with simpler molecular
structures that can more quickly affect the body, VandenPlas said.
Another likely factor is the consumption itself. You're taking in a
day's worth of calories (or more) in a short amount of time, she said.
That influx has consequences.
"Digestion takes a lot of energy. That's going to make you feel
sleepy," she said. "Your body is saying, 'Oh no, I've got a
lot of work to do.'"