Bird is the Word Turkey and Holiday Food Science
While the word “thanks” is included in our country’s favorite holiday’s name, we all know the real star of the day is the food. Kantha Shelke, PhD, CFS, a well-known food scientist and member for the Institute of Food Technologists (IFT), deconstructs the turkey-day menu by giving us the low-down on why all the flavors and textures go together so well and if l-tryptophan is the real culprit behind our post-meal food coma.

Why do most people like pumpkin pie warm or at room temperature?

  • People like pumpkin pie at room temperature, because at that temperature the filling has the perfect creamy texture and the crust is still delightfully crunchy and flaky.
  • People who enjoy warm pumpkin pie are seeking its aromas …and they relish the flavors in the filling and the buttery notes of the crust. 

Why do all the Thanksgiving flavors go so well together?

  • Our sense of smell is responsible for 80 percent of our eating experience.  Ingredients in the typical Thanksgiving Day dinner have many flavor components in common.
  • Root vegetables and members of the onion family share many similar flavor compounds.  
  • Roasted turkey and fried turkey have compounds in common with apples, chocolate, pumpkin, pecans, molasses, honey, parsley leaves, ham, tomatoes, and roasted vegetables.

How does cranberry sauce keep so long in a can vs freshly made?

  • Canned cranberry sauce can last for as long at two years in an unopened can because manufacturers make sure it has the perfect balance of acid and sugars. The absence of air in the can helps retain the flavors and the nutrients from getting oxidized, contaminated or spoiled.
  • Freshly made cranberry sauce will last for about a month in the refrigerator in a covered container.  Although cranberries are very acidic, the preparation involves the addition of sugar. It spoils more quickly than canned cranberry sauce because it is exposed to air and the environment repeatedly.

What is the science behind the pop-up thermometer in the turkey, how does it work? Can you trust it or should you always use a regular food thermometer?

  • Turkey is done when it reaches 165 degrees Fahrenheit.
  • If you don’t have a pop-up timer, you can use a meat thermometer to figure out the temperature of the meat. The pop-up timer, which often comes with a turkey that you buy at the grocery store, tells you if the part that it is stuck into is either cooked or not cooked.
  • While it is pretty reliable – within 1-2 degrees Fahrenheit, it is always a good idea to use a meat thermometer and check the thicker parts of the turkey meat to ensure that it is indeed done.

What is the difference between organic, wild, free-range, and conventional turkeys?

  • An organic turkey simply means that the bird has met the standards for USDA Organic certification including an organic diet and surroundings including bedding and grazing areas.
  • Wild turkeys are birds that were not domesticated or fed by humans— they’re essentially hunted for the meal.  In contrast, free range turkeys are birds that are not confined to a cage, but were allowed to roam and forage. Because their diets were augmented with grubs, worms, and grass, the flavor of their meat is distinctly flavorful, and the exercise supposedly improves the texture too.
  • Conventional turkeys are the classic turkeys in grocery stores that are available year round called broad breasted white, selectively bred to put on maximal breast meat in minimum growing time.

What about Thanksgiving makes you sleepy is it really l-tryptophan or overeating?

  • Although the after-dinner stupor associated with Thanksgiving is often attributed to the turkey and its amino acid l-tryptophan, which has a documented sleep effect, even those who omit the turkey will also complain about feeling sleepy after the feast. 
  • It is worth noting that l-tryptophan is also present to the same extent in other protein foods such as pork, ham, chicken and cheese …about 0.3 grams per 100 grams of the food.
  • Science has shown that L-tryptophan acts as a sleep inducer only when taken on an empty stomach. 
  • It is most likely that the quantity of carbohydrates and fats consumed during the meal redirects the blood to the digestive system and leaves one feeling sleepy, at least until they are revived by that additional slice of pie!

How does a starch help to thicken gravy? Is flour or cornstarch better?

  • Commercial starch – such as cornstarch or rice starch – is made of starch granules.  These little particles don’t do much when mixed with cold water or any liquid, but add a little heat to the mix and the individual starch granules get to work, absorbing liquid and swelling.  By the time the mixture nears boiling, the starch granules will have grown to about ten times their size at room temperature. These swollen starch granules form a thick but tender matrix for the flavorful turkey drippings in your gravy that thickens even more as it cools. 
  • Cornstarch is better than flour for thickening, because unlike flour which also contains protein and fiber, cornstarch is purely starch granules.


Kantha Shelke, PhD, CFS, IFT member

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