Trehalose, like maltose, is 45% as sweet as sugar. It does not brown like sugar, and has a very low hygroscopicity (moisture attraction), so it stays free-flowing and dry.

In trehalose, one glucose molecule is upside-down relative to the other. In maltose, the two glucose molecules are in the same orientation. This small difference reflects in the properties of trehalose. It does not brown when heated, it does not promote bacterial growth or tooth decay as much as maltose or sugar, and it is less attractive to moisture.

Use of trehalose:

- sweetener
- stabilizer
- thickener
- flavour enhancer
- used as a cryopreservation additive, where it protects cells from the effects of freezing and drying.

Trehalose protects and preserves cell structure in foods and may aid in the freezing and thawing process of many food products by assisting in the maintenance of the desired texture of the food. It is also heat stable. Trehalose is consumed as part of a normal diet in mushrooms, honey, lobster, shrimp and foods produced using baker's and brewer's yeast.

Taken from: http://sci-toys.com/ingredients/trehalose.html and http://www.caloriecontrol.org/trehalose.html