When a mixture of a food substance and Benedict’s solution was warmed, the solution changed from blue to brick-red. This indicates the presence of?

A. reducing sugar
B. fatty acid
C. sucrose
D. amino acid

Correct Answer:

Option A – reducing sugar

Explanation

During a water bath, which is usually 4–10 minutes, the solution of the mixture and Benedict’s solution should progress in the colors of blue (with no reducing sugar present), orange, yellow, green, red, and then brick red precipitate or brown (with high reducing sugar present). A color change would signify the presence of a reducing sugar.