Understanding the science of tea leaves leads you into the vast world of chemistry. It is here in the chemistry labs that we being to truly appreciate the complexity of the plant that produces our favorite beverage. Below are 3 fun facts on what drives the flavor in our tea cup.
- There are over 2,000 bioactive compounds in a single tea leaf. (Higdon, Drake, & Delage, 2005) Bioactive compounds are compounds that will interact with living tissue, i.e. the human mouth and sinus cavity, eliciting a response from us that could be either good or bad. The bulk of these compounds are polyphenols which directly affect the flavor and mouth feel of a cup of tea.
- The twisting and balling of leaves breaks open the cell membranes allowing polyphenol oxidase (enzyme) to combine with flavan-3ols (a type of flavonoid) to produce theaflavins and thearubigins (Higdon, Drake, & Delage, 2005). It is the theaflavins and thearubigins which give black and oolong teas their astringent feel in your mouth (that dry feeling in your mouth after you swallow).
- It is polyphenol oxidase that is the driver of oxidation. This enzyme protects the plant from microbial and viral infections (Wageningen University, 2014). In a tea plant, this enzyme lives in its own cellular compartment. Once the tea leaf is plucked, a set of cellular components have been broken allowing the polyphenol oxidase to interact with the other compounds and water in the plant. To stop the oxidation in tea, heat is used to remove water and inactivate the polyphenol oxidase.
If botany is more your thing, read about terroir to learn about the proper climate for growing tea.
Higdon, J., Drake, V., & Delage, B. (2005, January 31). Retrieved from Oregon State University, Linus Paulling Institute, Micronutrient Information Center: Tea: http://lpi.oregonstate.edu/mic/food-beverages/tea
Wageningen University. (2014, August 14). Enzymatic browning. Retrieved from Food Info Initiative of Wageningen University, The Netherlands: http://www.food-info.net/uk/colour/enzymaticbrowning.htm