A colorimetric method for total capsaicinoids in chili pepper (Capsicum) fruit is
described. The placental material of the pepper, containing 90% of the capsaicinoids, was physically
separated from the colored materials in the pericarp and extracted twice with methanol, capturing
85% of the remaining capsaicinoids. The extract, evaporated and reconstituted in acetonitrile, was
treated with Gibbs reagent to produce a beautiful blue product, easily detected by eye.
Semiquantitative measurement was made by comparison to a printed color chart. The simple
analysis required no electronic equipment or chromatographic separations, so is amenable to
classroom demonstration, introductory laboratory, and the field. Accuracy was demonstrated by
favorable comparison of results with those from a standard liquid chromatographic method for eight
varieties of chili pepper.