Innovative kombucha: Researchers brew tasty probiotic apple juice

Making kombucha with apple juice instead of tea is a “promising probiotic alternative” in terms of taste and bioactive substances, researchers reveal. They compared the biochemistry and flavor of kombucha with brews made from apple and passion fruit juices. The apple beverage contained high levels of flavonoids and phenolics, demonstrated antioxidant activity and ranked the highest among taste testers. 

Although kombucha is traditionally made by fermenting tea, brewers ferment other plant-based drinks to explore their nutritional properties and flavors. Few studies have determined whether liquids other than tea could be brewed as kombucha beverages with boosted antioxidant levels or unique flavors. 

The apple beverage and kombucha had comparable levels of phenolic compounds, which were higher than in the passion fruit beverage. All three drinks had similar amounts of the red-colored antioxidant anthocyanin.

The researchers aim to explore the health benefits and flavors of other fermented fruits in the future.

Kombucha brewing

A demand for healthier beverages and functional drinks, such as kombucha, is creating opportunities in the beverage market. Industry experts highlight consumer interest in lower sugar content and holistic solutions with an enhanced nutrition profile that benefits gut health. 

Brewers ferment sweetened tea (Camellia sinensis) with a symbiotic culture of bacteria and yeast (SCOBY) to make kombucha. This beverage contains beneficial bacteria from the fermentation process and bioactive compounds from the tea, such as flavonoids, phenolics and anthocyanins. These compounds may have antioxidant and anti-inflammatory properties. 

In their study, published in ACS Agricultural Science & Technology, the researchers fermented antioxidant-rich apple and passion fruit juices with a SCOBY for ten days at room temperature to determine the drinks’ physicochemical profile, bioactive composition and sensory characteristics.

The team notes that it is possible to create fermented beverages from passion fruit and apples distinct from kombucha. 

“The fermentation of apple juice produces a probiotic beverage with a sweet, pleasant, cider-like flavor and aroma,” reveals the report. “The superior flavor and bioactive profile of apple juice make it a promising alternative to kombucha, warranting further exploration of its potential health benefits.” 

Research suggests that kombucha may benefit people with insulin resistance or diabetes. For example, daily kombucha consumption for four weeks has been linked to lower fasting blood glucose levels. Another study suggests that kombucha reduced the glycemic index (GI) and insulin index when combined with a high-GI meal, while sugar-free soda water and diet lemonade did not. 

Taste test

After brewing their three beverages, the team asked 12 volunteer taste testers to evaluate their color, aroma and flavor. The apple beverage was amber, the passion fruit was yellow and the kombucha was gold. 

The volunteers reported stronger and fruitier aromas for the fermented fruit juices than the traditional kombucha. However, they scored the apple and tea drinks as their favorite beverage, finding the passion fruit drink too sour and bitter. 

The researchers explain: “Passion fruit exhibited relatively poor sensory acceptance due to its elevated acidity, astringency and alcohol content, likely attributed to its low total soluble solid, total sugar, reducing sugar and nonreducing sugar content.”

They state that both passion fruit and apples induce metabolic changes in yeast and bacteria, influencing alcohol production. The passion fruit juice’s acidity significantly affected alcohol production and “influenced product acceptance.”