Traditional fermented beverages, long valued for their unique flavours and health benefits, are now gaining recognition for their potential as probiotic carriers.
In many cultures, these drinks have been dietary staples for centuries. Among them, African fermented beverages show particular promise, with Uganda’s obushera – [NM1] a sorghum- or millet-based drink – emerging as a standout example.
Fermentation processes often involve lactic acid bacteria and yeasts, which not only enhance the flavour and shelf-life of foods but also improve their nutritional profiles by generating bioactive compounds. Many traditional beverages, such as kefir and kombucha, are popular for their perceived benefits to gut health. [NM2] Studies show that certain bacteria can prevent and manage gastrointestinal disorders, boost the immune system, and even improve mental health through the gut-brain axis.
However, even if these beverages contain live microorganisms, they generally do not contain probiotics, according to the widely accepted definition laid out by the FAO/WHO Guidelines for the Evaluation of Probiotics in Foods: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” The International Scientific Association for Probiotics and Prebiotics explains that “traditional fermented foods and beverages such as kombucha, sauerkraut, and kimchi typically do not meet the required evidence level for probiotics, since their health effects have not been confirmed and the mixtures of microbes are largely uncharacterized.”
African fermented products aside from obushera include uji, a Kenyan breakfast food made of boiled fermented millet flour, togwa, a Tanzanian non-alcoholic drink produced from the flour of maize and germinated finger millet. Although less known globally, these foods and beverages have been consumed for generations, offering potential for development into probiotic-rich functional foods.
Obushera, traditionally consumed in southwestern Uganda, is made by spontaneously fermenting sorghum or millet, which gives the drink a slightly sour taste. While the drink was historically made at home and consumed mainly in south and southwestern Uganda, in recent years it has been commercialised and gained popularity throughout the country, with more than 30 brands selling versions of the drink just in Kampala.
The natural fermentation process involves both lactic acid bacteria and yeasts, making it a suitable vehicle for probiotic enrichment. Recent studies have demonstrated that adding Lactobacillus rhamnosus yoba, a well-researched probiotic strain, to obushera enhances its probiotic content without compromising its sensory characteristics.
In trials, L. rhamnosus was shown to thrive in obushera, reaching concentrations of 82–92 colony forming units (CFU) per mL[NM3] , a level high enough to deliver meaningful health benefits to consumers. This strain, already known for reducing the severity of diarrhoeal diseases – a significant health issue in Uganda – makes obushera particularly promising as a functional beverage for both domestic and global markets. Additionally, L. rhamnosus contributes to the stability of the drink by lowering its pH, thus preventing spoilage and pathogenic contamination.
While the health benefits of probiotic-enriched drinks are well-documented, consumer acceptability remains a critical factor for market success. In the case of obushera, sensory studies have shown that its acceptability is influenced by factors such as the duration of fermentation and the type of cereal used. Variations in taste, texture, and aroma have been reported across different types of obushera – enturire and obutoko being sorghum-based, while ekitiribita and obuteire are millet-based.
Despite these variations, adding probiotics like L. rhamnosus does not significantly alter the sensory profile. Consumer panels in Uganda found probiotic-enriched obushera to be as acceptable as non-probiotic versions, with overall scores of 6.4 to 7.8 on a 9-point hedonic scale, showing that this innovation does not detract from the beverage's traditional appeal.
The spontaneous fermentation process used in traditional obushera production presents challenges for scaling up, particularly due to inconsistencies in quality and a short shelf life of four to seven days. However, recent innovations in stabilisation techniques have made it possible to extend obushera’s shelf life without affecting its probiotic content. Treatments involving the use of xanthan gum and pasteurisation have been shown to prevent the separation of solids and liquids, which is often mistaken for spoilage, while maintaining a shelf life of up to four months.
By using defined starter cultures such as L. rhamnosus, producers can ensure a more controlled fermentation process, leading to consistent product quality across batches. These innovations are essential for making obushera a commercially viable probiotic beverage.
In addition to its probiotic benefits, obushera is highly sustainable. Sorghum and millet, the key ingredients in the beverage, are drought-resistant crops that thrive in Uganda’s semi-arid regions with minimal inputs. This sustainability factor aligns with the growing consumer preference for eco-friendly, plant-based products in global markets.
As the global demand for probiotic-rich, functional beverages continues to rise, traditional fermented drinks like obushera have the potential to meet this need while preserving cultural heritage. By combining the health benefits of probiotics with the sustainability of traditional fermentation methods, obushera offers a promising future for both local and international markets.
