Why does eating tyrkey on Thanksgiving Day makes you sleepy?

Happy Thanksgiving Day Everyone !!!!!!!
In USA, people celebrating Thanksgiving day today. Thanksgiving Day is celebrated on the 4th Thursday of November in USA and 2nd Monday of November in Canada. The Turkey is main dish of a traditional Thanksgiving dinner. If you feel sleepy after the big Thanksgiving dinner. The truth is Turkey meat contains lots of an amino acid called L-tryptophan. Once we eat Turkey, L-tryptophan travels in the blood from the digestive system in to brain. In brain the changes L-tryptophan in to other chemical called Serotonin. Serotonin help us sleepy.

What is Emulsifiers?

An emulsifier keeps oils and water phase together, so a mixture of oil and water will not separate. Emulsifiers are very important in cosmetic science because most of cosmetic products had water and oil phases. Examples of emulsions are mayonnaise, butter, cream, paints and medicines. Some emulsions have tiny droplets of water in the oil. Other emulsions are droplets of oil in water. The most common used as an emulsifying agents are:

• Lecithin

Lecithin is light brown and yellow solid. Scientific names: 1,2-diacyl-sn-glycero-3-phosphatidylcholine .Common names: Lecithin also is known as lecithol, vitellin, kelecin
Chemical formula C40H80NO8P

• Phospohoric Acid

Phospohoric acid is a clear, colorless, odorless liquid that is irritating to the skin and eyes and moderately toxic, if ingested. It is used in the production of fertilizers, soaps, detergents, animal feeds, and certain drugs. Chemical Formula H3PO4

• Sobitan Monostearate

Sobitan Monostearate is waxlike creamy white powder.
Sorbitan monostearate is an ester of sorbitol and stearic acid.
The sorbitol end of the molecule is very soluble in water. The stearic acid end is soluble in fats. These properties make the molecule very good at making emulsions of oil and water.
Sorbitan monostearate is used as an emulsifying agent in cake mixes, icings, baked goods, puddings, imitation whipped cream, hemorrhoid creams, and creams to treat dry skin.