Alginate-Coated Probiotics that Go Down Easy


PhD student Tan Li Ling (left) and Associate Professor Joachim Loo with their coated bacteria powder. Credit: NTU Singapore

Scientists at Nanyang Technological University, Singapore (NTU Singapore) have developed probiotics with a unique edible coating that ensures the beneficial bacteria successfully reach the intestine once they are ingested.

Probiotics are defined by the World Health Organization as live microorganisms, which when administered in adequate amounts, confer a health benefit on the host. They have been shown to help prevent infections of the urinary and digestive tracts, and to maintain a healthy gut flora, which is linked to reducing the risk of obesity and promoting overall well-being.

However, several modes of delivering probiotics, including supplements and dairy products, have not been effective in ensuring they survive conditions in the human stomach to be delivered in quantities that would be sufficient to benefit one’s health. Many studies show that the bulk of probiotics delivered in commercial supplements and yogurts die off within the first 30 minutes of exposure to the acidic environment of the stomach.

In the NTU study, the probiotics — gut-friendly Lacticasei bacillus bacteria — are spray-coated with alginate, a carbohydrate derived from brown algae, protecting them from the harsh acidic conditions in the stomach. Through experiments simulating a journey along the human digestive tract, only the probiotics with the NTU-developed coating survived.

The bacteria are released only when they reach the small intestine, as the coating breaks down by reacting with phosphate ions, which are present in higher amounts in the small intestine.

Associate Professor Joachim Loo of NTU’s School of Materials Science & Engineering, who led the study, said: “In recent years, scientific studies have shown that the health of an individual is much more dependent on the help of ‘good bugs’ in our gut than we previously thought.”

“However,” he said, “probiotics are delicate microorganisms and cannot survive the harsh environment of our stomach. To increase the efficacy of probiotics as a dietary supplement, we sought to ‘parcel-wrap’ and deliver them to specific sites of the intestine where they function best. This moisture-stable packaging, through materials engineering, makes for a more effective probiotic delivery and extends the shelf-life of the supplements.”

Ms. Tan Li Ling, a PhD student at NTU’s School of Materials Science & Engineering, first author of the study, said, “We selected alginate as the coating material as it is safe for human consumption, of natural origin, and relatively low-cost. Alginate also exhibits acid-buffering properties, which can protect the probiotics against the harsh conditions caused by gastric acid.”

The results of the study were published in the peer-reviewed academic publication Carbohydrate Polymers in February. A patent application for the probiotics coating technology has also been filed through NTU’s enterprise and innovation company, NTUitive.

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