SINGAPORE — Researchers at the National University of Singapore have found a use for old, unsold bread that normally is donated to charities or sold as animal feed. The researchers in the Department of Food Science and Technology have incorporated the bread into a probiotic drink.

The creamy drink is slightly fizzy and sweet, according to the researchers. It may be stored at room temperature for up to six weeks while maintaining at least 1 billion live probiotic cells per serving, which is recommended by the International Scientific Association for Probiotics and Prebiotics to deliver maximum health benefits.

The researchers have filed a patent for the zero-waste process used to make the probiotic beverage. They want to work with industry partners to commercialize the drink. A video on the drink may be found here.

“There is currently a lack of non-dairy probiotic food and beverage options in the market,” said Liu Shao Quan, PhD, associate professor. “So our refreshing and healthy new product will help to fill this gap. Our invention also enables bread makers to give their unsold products a new lease of life. We are confident that the bread-based probiotic beverage will have a strong appeal to those who are environmentally conscious.”

Miss Nguyen Thuy Linh, one of the researchers, said she usually cannot finish a loaf of bread before the expiration date.

“It is a waste to discard the nutrients in bread,” she said. “So as a food science student, I was motivated to find a way to repurpose surplus bread by upcycling it into something delicious and nutritious.”

The research was her final-year undergraduate project. She completed her undergraduate studies at the National University of Singapore last year.

The research team tested different types of bread and decided to focus on white sandwich bread since it is commonly available in supermarkets. They took nine months to perfect their recipe.

The first step involves cutting the bread into small pieces and blending the pieces with water to get a bread slurry. After the slurry is pasteurized and probiotic bacteria and yeast are added, the mixture is left to ferment. The entire process takes about one day.

“Most probiotic drinks are dairy-based and unsuitable for people with lactose intolerance,” said Toh Mingzhan, PhD, a research fellow at the university. “Our bread-based probiotic beverage is non-dairy, making it an attractive option for this group of consumers.”