Sugar poses one of the most pressing health problems in the modern world – not least because it’s just so delicious. Rather than quitting sweets cold turkey, low-calorie alternatives to sucrose could make tasty treats that are at least less bad for us. And now, researchers from Tufts University have developed a more efficient method for producing one such sweetener, using farms of bacteria.
The sugar in question is called tagatose, which the FDA says is “generally regarded as safe.” It’s 92 percent as sweet as sucrose – regular old table sugar – but because the human digestive system doesn’t metabolize as much of it, it only has 38 percent of the calories. That, in turn, means tagatose has a much smaller effect on blood glucose and insulin, making it safe for diabetics. And to cap it off, tests show that it doesn’t contribute to cavities or tooth decay.
But, of course, there’s a catch – tagatose is a little complicated to produce. Normally, it’s done by hydrolyzing lactose to make galactose, which is then isomerized into tagatose, which then needs to be purified and crystallized into a solid, usable form. Yields from this process are low, at less than 30 percent.
The researchers on the new study, however, claim to have reached yields of up to 85 percent. They used the same enzyme – L-arabinose isomerase (LAI) – as usual to turn galactose into tagatose, but with one major difference. Rather than using it in a solution where the enzyme is unstable, the team used food-safe bacteria called Lactobacillus plantarum, which produce LAI.
Because the bacteria keep the enzyme safe within their cell walls, the tagatose yield was boosted up to 83 percent at 50° C (122° F), and it was produced faster than usual. The researchers managed to squeeze even better performance out of the bacteria by treating them with a small amount of detergent. That made their cell walls slightly “leaky” without killing them, letting the sugars move in and out faster. This bumped yields up to 85 percent, and shaved a few hours off the process.
It’s a promising start, but the researchers say there’s still plenty of work to do to scale up the process to commercial levels.
The research was published in the journal Nature Communications.
Source: Tufts University
