This article was originally published in December 2019.
Welcome to our Christmas dinner special. We’ll be talking about the food science of traditional Christmas dinner cuisine. Have you ever thought about the science behind your Christmas dinner? If the answer is yes, read our articles on dishes that are commonly served as part of traditional Christmas dinner. Our inaugural article will be on none other than the centrepiece of Christmas dinner: the turkey!
Many people’s Christmas dinner wouldn’t be complete without a Christmas turkey. In fact, an average of 10 million turkeys were cooked in the United Kingdom on Christmas Day in 2018.
What happens when you roast a turkey?
After you’ve prepared your turkey and put it in the oven, the meat changes from a semi-translucent pink to an opaque white colour. This is because the turkey meat is made up of muscle fibres, tissue and fats. The muscle fibres are made up of two major protein filaments: actin and myosin. When the turkey cooks under high heat, the heat causes these proteins to denature and coil, thus contracting the muscle. The bonds between the proteins in the meat start to break down and unravel, making the turkey meat tender. When the connective tissues (consisting of collagen, reticulin and elastin) of the turkey is subjected to heat, the high temperature of the oven breaks down the collagen into a soft, gelatinous consistency which gives it a better texture. Regulating the cooking temperature ensures that the muscle fibres and the connective tissues break down to produce a tender turkey, leaving it in too long can overcook the muscle proteins, taking the turkey out of the oven too early risks the connective tissues not breaking down properly, resulting in a tough texture either way. Using aluminium foil to protect the turkey breast, deflects the heat from the breast, preventing it from over-cooking and drying the meat.
According to science a perfectly cooked turkey needs to be place in an oven heated between 140 and 200°C to make sure the Maillard reactions release chemicals that give the turkey flavour. This cooking process is complemented by the Maillard reaction which is a chemical reaction between amino acids and a reducing sugar which creates colour and flavour compounds in food. As the turkey cooks, the Maillard reaction produces various flavour compounds including: furans (meaty, burnt), furanones (sweet, caramel), pyrazines (cooked, roasted), thiophenes (meaty, roasted). It was initially discovered in 1912 by Louis-Camille Maillard. This reaction is also known as ‘non-enzymatic browning’ as it gives food a brown colour.
Where does the moisture in the turkey come from?
Did you know that water makes up 60% of the turkey’s body? Most of this water is bound to the proteins in the meat so, when the turkey cooks, water molecules are released which contributes to the tenderness of the meat. As this is a condensation reaction, water is released as a product of the Maillard reaction along with the various flavour compounds. If too much water evaporates from the turkey, this can result in a tough, dry turkey.
To baste or not to baste?
As the turkey roasts in the oven, you’ll want to baste the turkey. This is the process of brushing the juices (the fats and water released as it cooks) that are in the roasting tin back over the meat as it cooks. It is commonly thought that basting the turkey makes the meat more tender - science has proven otherwise. Basting doesn’t really help because the turkey skin acts as a cover which prevents the juices from getting through to the meat. However, if you baste the legs and wings of a turkey with the hot juices, this will help slow the cooking of the legs and the wings to ensure the whole turkey gets enough time in the oven to maintain the tender texture and taste throughout.
Are you feeling sleepy?
After enjoying your Christmas Dinner, you’ll find that you feel sleepy, barely being able to keep your eyes open. There used to be a common understanding that tryptophan, an amino acid found in turkey meat, is responsible for making you sleepy. Tryptophan is an amino acid, which is a precursor for the brain chemical: serotonin. Although turkey is high in tryptophan, it’s not the only amino acid. There are many amino acids that make up the proteins in turkey meat. The reason why you would feel sleepy after Christmas Dinner is because you may have consumed a large meal which will take a lot of energy to digest, making you feel tired.
So now you’ve learned a lot about the Christmas turkey, please come back next week for another Christmas Dinner dish. Can you guess which dish is we’re going to be explaining the food science for? It’s ??? ?????! Tweet us @IFSTNews with your guesses and don’t forget to share this article with your friends and family!