Researchers at Fraunhofer IME have partnered with metaX Institut für Diätetik GmbH and candidum GmbH to develop a new type of protein-based sweetener. Called NovelSweets, the project is supporting the German Federal Ministry of Food and Agriculture in its efforts to reduce the sugar content of ready-made foods and beverages.
The new sweetener is made from sweet-tasting proteins, molecules that occur naturally in some plants and bind readily to taste receptors for sweet flavors on the tongue. Brazzein, found in the African plant Pentadiplandra brazzeana, is one of the best-known sweet proteins; however, it is difficult to extract from the plant. Instead, the NovelSweets project is developing new protein varieties based on the protein sequence of brazzein.
This process involves the use of biotechnology and microbial fermentation. The gene encoding the sweet-tasting protein is implanted into yeast cells, which are multiplied in a bioreactor to produce as high a yield as possible. The product is then purified and dried. Called X3, the resulting sweetener is around 10,000 times sweeter than table sugar and three to four times sweeter than natural brazzein.
The method enables the optimization of the pH and temperature stability of the proteins, along with the improvement of properties such as sweetness, flavor, and sensory attributes. For example, brazzein is said to have a scratchy feeling when eaten, but this can be removed by changing the protein sequence.

“Impressive improved taste”
X3 is virtually calorie-free and said to have a similar taste to honey. It will initially be added to beverages; project partner metaX is currently developing the first range of products made with the sweetener, including a beverage powder made with cocoa. However, the manufacturing process will need to be optimized and further product validation measures introduced before the approval process for the ingredient can begin.
Worldwide, several types of sweeteners made with sweet proteins have been developed. In the US, Oobli achieved GRAS (generally recognized as safe) status for its Fruit Sweet Protein, made using precision fermentation, earlier this year. MycoTechnology has developed a sweetener made from a sweet protein found in honey truffles, while Shiru and Ajinomoto formed a partnership earlier this year to develop and commercialize sweet proteins that could replace sugar and sweeteners. Additionally, Abu Dhabi-based Novel Foods Group announced plans in March to build a $500 million precision fermentation hub to produce brazzein.
“X3 is impressive for its improved taste compared to the artificial sweeteners that have been available to date, as our tastings with test subjects have shown,” said Dr. Stefan Rasche, a researcher at Fraunhofer IME in Aachen. “Since it is entirely sugar-free in addition to having practically no calories, our modified brazzein version does not cause cavities or increase people’s blood sugar levels.”