Which compound is specifically NOT detected by Benedict's reagent?

Benedict's reagent is a chemical test commonly used to detect the presence of reducing sugars. Reducing sugars are those that can donate electrons to another chemical and typically include monosaccharides and some disaccharides.

In the case of sucrose, it is a disaccharide composed of glucose and fructose. However, sucrose is not a reducing sugar because the glycosidic bond between its two sugar units does not allow for oxidation; it has no free aldehyde or ketone group available for reduction. As a result, when sucrose is mixed with Benedict's reagent, there is no change in color indicating the presence of reducing sugars.

In contrast, maltose, fructose, and dextrose can all be detected by Benedict's reagent. Maltose, being a reducing disaccharide, has a free aldehyde group. Dextrose, a form of glucose, is a reducing sugar as well. Fructose, despite being a ketose, can tautomerize to an aldehyde form under the right conditions and can reduce the reagent. Therefore, these three compounds are detected by Benedict's reagent, while sucrose is specifically not detected due to its lack of a reactive aldehyde or ketone group.