Fruitier kombucha put to the taste and nutrition test

Kombucha is usually made by fermenting tea, but brewers are now fermenting other plant-based drinks to explore nutritional properties and flavours. Researchers recently compared the biochemistry and flavour of kombucha with brews made from apple and passionfruit juices. They found that the apple beverage contained high levels of bioactive compounds, or flavonoids. It also ranked highly among taste testers, signalling a promising kombucha alternative.

To make kombucha, brewers ferment sweetened tea with a spongy disc of microbes known as a SCOBY, or symbiotic culture of bacteria and yeast. The resulting beverage contains beneficial bacteria from the fermentation process and bioactive compounds from the tea, including flavonoids, phenolics and anthocyanins that may have antioxidant and anti-inflammatory properties.

Few studies have investigated whether liquids other than tea could be brewed as kombucha-like beverages with boosted antioxidant levels or unique flavours. So Socorro Vanesca, Frota Gaban and colleagues at the Federal University of Ceará fermented antioxidant-rich apple and passionfruit juices with a SCOBY to find out more.

After fermenting apple juice, passionfruit juice and tea in separate jars for 10 days at room temperature, the researchers measured the levels of several bioactive compounds in each brew and found the following:

• The apple beverage had the highest level of flavonoids, followed by kombucha and the passionfruit drink.
• The kombucha and apple beverages had comparable levels of phenolic compounds that were higher than those of the passionfruit beverage.
• All three brews had similar amounts of anthocyanin, a red-coloured antioxidant.

The researchers asked 12 volunteer taste testers to evaluate each beverage’s colour, aroma and flavour. The taste testers noted an amber colour for the apple beverage, yellow for passionfruit and gold for the kombucha.

Kombucha (left) and kombucha-like beverages from passionfruit (centre) and apple (right) juices. Image has been cropped from the original and appears courtesy of the study authors under CC BY 4.0

The volunteers reported stronger, fruitier aromas for the fermented fruit juices compared with the tea. However, the passionfruit drink tasted more bitter than the sweeter apple and tea drinks, both of which received equal votes as the favourite beverage.

Because fermented apple juice has more flavonoids and a pleasant taste compared with the other beverages, the researchers say it could be a successful alternative to kombucha made from tea.

They now plan to explore health benefits and flavours of other fermented fruits in the future.

The findings have been published in ACS Agricultural Science & Technology

Top image credit: iStock.com/Pornpimon Rodchua