Sugar substitutes such as saccharin, aspartame, maltitol and sorbitol often come with stomach bloating, strange aftertaste, and even concerns for long term health risks. Traditional sugars such as sucrose, fructose, and glucose come with well-known health risks including Type 2 diabetes and obesity. Researchers based at Tufts and Harvard University have developed a method to manufacture a sweet bi-product of glucose called tagatose.
Tagatose is not an artificial sweetener, but is a breakdown product of glucose, and is very similar to the sugar galactose, which is commonly found in dairy products. Unlike more standard forms of sugar, tagatose has a very low glycemic index, meaning that it is less likely to lead to rise in blood sugar and insulin levels. In addition, it is about 92% as sweet as sucrose, or table sugar. Its consistency is similar to that of standard sugars, making it easier to use in food preparation compared to the powdered quality of many artificial sweeteners. And because it is roughly as sweet as table sugar, quantities used for cooking or baking can match those of regular sugar. Conversely, powdery sugar substitutes such as aspartame or even stevia can be more than 300 times as sweet as sucrose, thereby altering the bulk volume needed for food preparation. Tagatose is a natural sugar, but is only present in 0.2% of natural sources such as fruits and dairy.
The extraction process developed by the research group based at Tufts and Harvard, along with collaborators at Manus Bio in Massachusetts and Kcat Enzymatic in India, involves utilization of an Escherichia coli (E.coli) bacteria to produce an enzyme that efficiently breaks down glucose to galactose and then galactose to tagatose. This won’t mean that the tagatose product has the dreaded E.coli toxins that lead to gastrointestinal infections, as it is purely the enzyme itself that simplifies the output of tagatose in larger amounts that are present naturally.
Tagatose tends to have a similar texture and taste to sucrose, with 60% of the calories and an approved consumption safety profile by the U.S. Food and Drug Administration. In addition to having a lower glycemic index and lower impact on insulin production than sucrose, it has dental health benefits. Unlike sucrose, which tends to feed the oral bacteria that lead to cavities and poor oral health, tagatose blocks some of these cavity-causing bacteria from growing, and may also have some benefits on intestinal bacteria and the gut microbiome.
The mechanism of synthesizing tagatose involves the splicing of an enzyme from slime mold into the E.coli bacteria, leading to a reversal of production of glucose from galactose to galactose, followed by tagatose, from glucose. This is yet another example of how seemingly toxic substances such as infectious bacteria and mold do not necessarily have toxic effects in the laboratory setting. This is an important reminder when learning of a harmful (or helpful) substance that has impact in a petri dish but has a wholly different impact out in the wild.