Do L-sugars (enantiomers of natural sugars) have a sweet taste?

Question

I'm wondering about how L-sugars taste. They are obviously not digestible by humans, but what do they taste like? If they are sweet, too, why isn't sucrose with the unnatural chirality used as a zero-calorie table sugar substitute?

Answer 1

This is an interesting question. In fact, I had just read about this a few weeks ago. As you know, it is D-glucose that is naturally occurring and it is the sugar our bodies metabolize. The L-enantiomer was proposed to be a substitute since it has the same sweet taste, but our bodies can't metabolize it. Therefore, it was proposed to be an effective substitute for the D-glucose. The L-glucose could therefore be a low calorie alternative and even diabetes can use it. But, the cost of making it is too high to be commercialized.