Tea type changes kombucha chemistry and antioxidant activity, study finds
Researchers found kombucha made with different teas developed distinct aromas, chemical profiles and antioxidant activity under the same fermentation conditions.
By Priya Raghavan · Science Reporter
3 min read
The tea used to brew kombucha can change far more than its flavor, according to researchers from Wroclaw Medical University and the Wrocław University of Environmental and Life Sciences. In a study published in Food Chemistry, the team reported that kombuchas made from different teas developed distinct chemical makeups, aromas and antioxidant activity even when fermented under the same conditions.
The researchers compared kombucha prepared from black, green, white, oolong and pu-erh teas, Wroclaw Medical University said. The work focused on whether the starting tea acts as a key ingredient shaping fermentation, rather than as a neutral base for the drink.
Associate Professor Helena Moreira of Wroclaw Medical University said the type of tea provides a matrix that affects how fermentation unfolds and what the finished kombucha contains. According to the university, teas differ in polyphenols, catechins, caffeine and other bioactive compounds, which are then altered by the microbes in a SCOBY.
Fermentation produced different chemical profiles
Kombucha is made by fermenting sweetened tea with a SCOBY, a symbiotic culture of bacteria and yeast. Wroclaw Medical University said yeasts convert sugars into alcohol and carbon dioxide, while bacteria turn those compounds into organic acids, including acetic acid and gluconic acid, which help create kombucha’s tart taste.
The study found that fermentation also changed compounds already present in tea, including polyphenols, catechins and volatile molecules linked to smell and flavor. The researchers reported increases in compounds associated with fruity and floral aromas, including linalool and 2-phenylethanol, while some compounds found in brewed tea declined as fermentation continued.
To track those shifts, the team used chromatographic methods and mass spectrometry, according to Wroclaw Medical University. Those techniques allowed the researchers to compare hundreds of compounds across kombuchas made from the five tea types.
Moreira said the researchers were struck by how much the drinks diverged despite being produced under identical fermentation conditions. The university said each tea led to a different profile of volatile aromatic compounds in the finished beverage.
Green and oolong stood out in lab tests
The study reported that green tea and oolong tea kombuchas showed the strongest antioxidant activity and the greatest ability to neutralize free radicals among the samples tested. Free radicals are reactive molecules that can damage cells, and researchers study antioxidants for their possible role in health, according to Wroclaw Medical University.
The researchers cautioned that the findings came from laboratory analysis and do not prove specific health effects in people. Moreira said clinical studies would be needed to confirm whether particular kombucha types affect human health.
The university said the sensory differences were also clear. Green tea kombucha tended toward fresher, more vegetal aromas, while oolong kombucha showed stronger floral and fruity notes. Black tea and pu-erh kombuchas were described as richer and earthier, with more evident fermentation characteristics.
The findings add to broader research interest in fermented foods, according to Wroclaw Medical University. The study suggests kombucha should be treated as a category of drinks shaped by both the tea and the fermenting microbes, rather than as one uniform beverage.
This story draws on original reporting from ScienceDaily.