Rapid determination of capsaicinoids by colorimetric method

Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid-liquid extraction and liquid-liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide). In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R-2 was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 mg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time. Copyright (C) 2016, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC.