3. Biochemical transformations and nutrition

3.1 Composition

Freshly harvested tea leaves have a complex composition, with protein content ranging from 15 to 20% of dry weight, soluble carbohydrates from 5 to 7%, minerals and trace elements around 5% and amino acids from 1 to 4%. Once brewed, 1 L of tea contains : 1 g protein, 70 mg lipids (including 40 mg polyunsaturated fatty acids), 0 g carbohydrates, 4 g ash, minerals (potassium (255 mg), magnesium (20 mg), sodium, phosphorus, iodine, calcium (2 mg), manganese, zinc, copper, iron, selenium (0.5 μg) and B vitamins (B3/niacin, 1 mg, B2/riboflavin (0.15 mg), B5/pantothenic acid (0.11 mg), B9/folates (49.5 μg).

Based on polyphenol composition, there is a wide variety of teas, with a general shift from aglycone forms (epicatechin and catechin) in older...