Determination of capsaicinoids in peppers by microwave-assisted extraction-high-performance liquid chromatography with fluorescence detection.

A new method has been developed for the extraction of capsaicinoids (nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin) in peppers employing microwave-assisted extraction. The parameters studied are: extraction solvent (methanol, ethanol, acetone, ethyl acetate and water), temperature (50-200 degrees C), sample quantity (0.1-1 g), volume of solvent (15-50 mL) and the extraction time (5-20 min). The results found for the optimum conditions are: 125 degrees C as extraction temperature, 25 mL of solvent, 0.5 g of freshly triturated peppers and extraction for 5 min, employing 100% ethanol as solvent. The capsaicinoids obtained were stable under the optimised extraction conditions. The resulting method presents a high degree of reproducibility (R.S.D.<6%).