Researchers ferment gut-friendly tea and coffee with probiotics

13 Jan 2021 --- A team of researchers at the National University of Singapore (NUS) have created plant-based tea and coffee products filled with live probiotics.

The move comes amid a sharp rise in demand for gut-friendly probiotic products and a concern over widespread mislabeling and inauthenticity highlighted in recent research. 

Billions of live probiotics
The probiotic beverages created at NUS contain over one billion live probiotics units and can be stored for up to two weeks, say the researchers. This is the daily quantity recommended by the International Scientific Association for Probiotics and Prebiotics. 

The product development was supervised by associate professor Liu Shao Quan from the Department of Food Science and Technology at the NUS Faculty of Science. 

He explains that his team chose coffee and tea for their vegan profile and used fermentation to improve its health benefits. 

“Coffee and tea are two of the most popular drinks worldwide and are both plant-based infusions. As such, they act as a perfect vehicle for carrying and delivering probiotics to consumers.” 

“Most commercially available probiotic coffee and tea drinks are unfermented. Our team has created a new range of these beverages using the fermentation process as it produces healthy compounds that improve nutrient digestibility while retaining the health benefits associated with coffee and tea,” he says.  

Probiotic tea 
Each tea and coffee product contains over 1 billion probiotic units and can be stored for up to fourteen days.Wang Rui, a doctoral student from NUS Food Science and Technology, is responsible for creating the probiotic tea product. 

Nutrients were added into a tea infusion, followed by a careful selection of specific probiotics. The tea mixture is left to ferment for two days, after which it is ready to drink, Rui explains. 

Any kind of brewed tea can be used in this process, and throughout the fermentation process, the original flavor of the tea is largely retained, with fruity and floral notes emerging.

“The probiotic tea tastes like fruit tea with a little bit of acidity and a similar mouthfeel to the original tea. Drinkers can add sweeteners and milk, or cream, based on their preferences,” she says.

Many of the health benefits of tea, such as its antioxidant and anti-inflammatory properties, have been linked to its polyphenol molecules. 

The tea’s polyphenol contents are retained using a patented fermentation process, and an additional antibacterial agent – phenylacetate – is produced after fermentation, Rui asserts. 

Probiotic coffee 
Alcine Chan, another NUS doctoral student, created the probiotic coffee product by adding a specially selected assortment of nutrients and probiotics to brewed coffee grains. 

The mixture is then left to ferment for 24 hours and placed in a refrigerator. 

“The formulation is tricky, especially relating to the type and amount of nutrients added and the probiotic combination. Not every probiotic can grow in coffee brews,” she explains. 

“Adding too few nutrients will not enable probiotic growth, while adding too many nutrients will give an unpleasant taste.”

Chan formulated several prototypes of the probiotic coffee with varying flavors. 

“Some of the probiotic coffees give better-balanced acidity, some give better mouthfeels, some have deeper smoky flavors, and some can retain the coffee flavor better after long-term storage.”

The caffeine content is also retained in the production process, she asserts. 

The probiotic coffee also keeps its chlorogenic acid content, which has been linked to various health benefits, including weight management and lowering blood pressure. 

Edited

By Louis Gore-Langton