Scientists discover tagatose: a natural alternative to sugar with only a third of its calories.

Scientists have discovered a type of sugar that is characterized by its sweet taste, low calorie content, and the fact that it does not cause a rise in insulin levels.

Artificial sweeteners were supposed to make sugary foods and drinks healthier, but today, some of the most popular calorie-free alternatives are raising new concerns.

A promising natural alternative may one day be produced on a much larger scale, using enzymes extracted from slime mold.

Sweet taste and limited calories

This natural sugar is called “tagatose,” and it not only has a sweet taste of 92% sucrose (or table sugar), but also contains approximately one-third of its calories.

Also, this new sugar does not raise insulin levels like sucrose or high-intensity artificial sweeteners, making it a potentially attractive option for diabetics or those with blood sugar disorders.

According to the Science Alert website , researchers from Tufts University, in collaboration with the biotechnology companies Manus Bio in the United States and K-Cat Enzymatic in India, conducted a pilot study that proved the possibility of producing tagatose in a sustainable and efficient manner, a challenge that has long hindered market growth.

The study was published in the journal “Cell Reports Physical Science”. 

Tagatose metabolism

Tagatose is a rare, naturally occurring sweetener found in trace amounts in some dairy products and fruits. It offers a potentially healthier alternative to sucrose and artificial sweeteners, which can cause a sharp spike in insulin levels.

One of the main reasons tagatose does not have the same effect is that a large part of it ferments in the large intestine and is only partially absorbed into the bloodstream via the small intestine.

In the intestines, the rare sugar tagatose is metabolized in a similar way to the fruit sugar fructose, meaning that people with fructose intolerance may want to avoid it. However, tagatose is generally considered safe for consumption by the U.S. Food and Drug Administration and the World Health Organization.

Tagatose is also considered beneficial for teeth and may offer vital benefits to the oral microbiome. 

Unlike sucrose, which feeds certain types of bacteria in the mouth that contribute to tooth decay, preliminary research suggests that tagatose limits the growth of harmful oral microbes.

Tagatose can also be added to foods during baking, unlike many other high-intensity sweetener alternatives.

Limited and expensive production

Despite the potential, the market for tagatoz is currently limited due to limited production, as the production methods used are expensive and inefficient, according to Science Alert, quoting bioengineer Nick Nair from Tufts University. 

Nair says, “We have developed a method for producing tagatose by engineering E. coli bacteria to function as miniature factories, loaded with the appropriate enzymes to process abundant amounts of glucose and convert it into tagatose.”

The researchers introduced into these bacteria a newly discovered enzyme from slime mold called galactose-1-phosphate selective phosphatase. This enzyme converts glucose to galactose, and then another enzyme converts this product to tagatose.

Using this new series, Nair and his colleagues showed that the productivity of the tagatose can reach 95%, which is much higher than the current rate of between 40 and 77%.

Some estimates suggest that the tagatooz market will reach a value of US$250 million by 2032.