The dominant substance that forms the aroma of green tea is aromatic oil, which has a low content and complex composition in fresh leaves, generally below 0.02%. It contains a variety of chemical components, including acids, aldehydes, ketones, alcohols, alkenes, etc.
There are two main types of aromatic oils that affect the aroma of tea. One type is low boiling point green leaf alcohol, which accounts for about 60% of the total amount of ancient aromatic oil, as well as low boiling point green leaf aldehyde. They have a strong green aroma, which is not good for the quality of green tea, but their boiling point is low, usually between 130-150 ℃, and they are easily volatile when heated. Another type of aromatic oil with various good aromas includes benzyl alcohol, alcohols, etc. Among them, linalool has a higher content and higher aroma, and 2% of ancient fresh leaf aromatic oil. These aromatic oil components with good aroma have a high boiling point, reaching over 200 ℃.
In addition, some esters and amino acids with certain flavors also have certain aromas. Phenylalanine has a rose like aroma, while glutamic acid and alanine carry floral fragrance. At the same time, during the heating process, they can also form "sweet aroma", "high fire aroma", "burnt aroma", etc.
