Oolong Vs. Green Tea

Tea comes in a few different forms, including green and oolong tea, which are defined by their processing. Green tea is light green in color and flavor, and oolong tea has a stronger taste and light brown color. All teas are made from the dried leaves of the Camellia sinensis plant. According to the Linus Pauling Institute at Oregon State University, tea is second only to water as the most widely consumed beverage in the world.

Definitions

Green tea is made from mature tea leaves that have undergone minimal processing. For some green teas, the leaves are steamed or fired in an oven to remove a compound called polyphenol oxidase and then dried before being packaged for sale. Other green teas are withered before being steamed or fired. Oolong tea, also known as wulong tea, is bruised before steaming or firing. This releases some of the polyphenol oxidase, which causes catechins in the leaves to bind together in dimers and create theaflavins and thearubigins, a process called fermentation. Oolong teas are not left to ferment as long as black teas, so they have a flavor somewhere between green and black tea.

Phytochemical Types

Tea contains many health-promoting compounds, but their levels and ratios differ depending on the type of tea. Catechins, which have been linked to cancer prevention, heart protection and antioxidant activity, are highest in unfermented teas such as green tea. Epigallocatechin gallate, epicatechin, epigallocatechin and epicatechin gallate are the main catechins in green tea. The process of fermentation converts some of these into theaflavins and thearugbins, so the levels of these compounds is higher in oolong tea.

Antioxidant Content

Antioxidants, compounds that neutralize free radicals in the body and prevent them from causing cellular damage, can consist of nutrients, such as vitamins, or phytochemicals. A 2009 study in the "Journal of Agricultural Food Chemistry" that measured the total content of antioxidant polyphenols in a variety of beverages found that green tea had 115 mg per 100 ml and oolong tea had 39 mg per 100 ml.

Caffeine

The caffeine content of oolong tea is slightly higher than that of green tea, but both are much lower than the caffeine in black tea. An 8-oz cup of green tea made with one teabag contains between 8 and 30 mg of caffeine, according to the Stash Tea Knowledge Center. Oolong tea has between 12 and 55 mg of caffeine per cup. The specific number depends on factors such as the age of the leaves, the growing conditions of the tea and the brewing method and time. Both green and oolong tea can be decaffeinated, although a small amount of caffeine always remains even after decaffeination.

Health Effects

Green tea's effects on health have been studied far more extensively than oolong tea's effects, but more research is required for all tea types, explains the Linus Pauling Institute at Oregon State University. Green tea has been linked to the prevention of some types of cancer. Oolong tea and green tea may also have an impact on weight loss and the prevention of cardiovascular disease.