Rapid determination of capsaicinoids by colorimetric method
Wang-Kyun Ryu a,1, Hee-Woong Kim a,1, Geun-Dong Kim a, Hae-Ik Rhee a,b,*
a Department of Medical Biotechnology, Kangwon National University, Chuncheon, Republic of Korea
b Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Republic of Korea
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 solideliquid
extraction and liquideliquid 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, R2 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.
Keywords: capsaicinoids, colorimetric method, liquideliquid extraction, solideliquid extraction