Iodine solution

Iodine solution or Lugol's reagent has yellowish brown color. Iodine interacts with and binds to a structure in the starch molecule, forming a structure that transmits a dark bluish black color.

Figure 1. (-) is negative result;(+) is positive result.

Monosaccharides and other polysaccharides cause no color changes.

Read more:

• Food biohemistry test