Frontiers in Plant Science | Researchers from the University of California, Davis, etc., used an optimized HPLC method to quantitatively analyze the capsaicin content and spiciness ranking of different chili pepper varieties.
Capsaicin is the main active compound in chili peppers that imparts their spiciness, playing important roles in food flavoring, health promotion, and biocontrol. However, systematic comparative studies on capsaicin content among different chili pepper varieties remain limited. Recently, a research team from the University of California, Davis, and other institutions used optimized high-performance liquid chromatography (HPLC) to quantitatively analyze the capsaicin content of seven chili pepper varieties (Habanero, Thai Pepper, Serrano, Harappa, Lion’s Son, Bobrano, and Anaheim), establishing a spiciness ranking system based on dry weight content. The related research results, titled “Quantitative profiling of capsaicin content in seven chili pepper cultivars using optimized HPLC,” were published in the academic journal Frontiers in Plant Science.
This study first established and validated the detection performance of the HPLC-UV method, using a reversed-phase C18 column with isocratic elution (acetonitrile:water = 70:30, 0.5% formic acid), a detection wavelength of 220 nm, and a flow rate of 0.4 mL/min. Method validation results showed: linear range 0.5–200 ppm, R² = 0.9999; limit of detection 0.5 ppm, limit of quantitation 0.75 ppm; recovery 90%–100%; intra-day and inter-day precision RSD <6% and <5%, respectively. This method is accurate and reliable, suitable for the quantification of capsaicin in chili peppers.
Two extraction methods (wet extraction: direct extraction from fresh samples; dry extraction: extraction after drying at 60℃) were used to analyze seven varieties. Results showed that dry extraction was significantly more efficient than wet extraction: the capsaicin content extracted by dry extraction in Havana was 542% higher than that extracted by wet extraction, in Thai chili peppers 475% higher, in Serrano chili peppers 986% higher, and in Harappa chili peppers 1109% higher. Moisture content determination showed that the moisture content of chili peppers ranged from 82.9% to 94.2%, with the highest in Bobrano and the lowest in Thai chili peppers. Dry extraction improved extraction efficiency by removing moisture.
Quantitative analysis (mg/kg dry weight) of capsaicin content extracted from seven varieties using the dry method showed that: Habanero had the highest content (4777.6 ± 720.9), followed by Thai pepper (1844.8 ± 239.4), Serrano (1069.3 ± 152.2), Harappa (16.4 ± 5.0), Lion’s Son (6.4 ± 0.6), Bobrano (2.5 ± 0.2), and Anaheim had the lowest (1.0 ± 0.06). The spiciness ranking was: Habanero > Thai pepper > Serrano > Harappa > Lion’s Son > Bobrano > Anaheim. The capsaicin content of Habanero was 2.58 times that of Thai pepper, 4.47 times that of Serrano, and approximately 290 times that of Harappa.
Based on capsaicin content, the Scoville Heat Unit (SHU) values (mg/kg capsaicin × 16) were calculated as follows: Havana pepper approximately 76,441 SHU, Thai pepper approximately 29,517 SHU, Serrano pepper approximately 17,109 SHU, Harappa pepper approximately 263 SHU, Lion’s Son pepper approximately 102 SHU, Bobrano pepper approximately 39 SHU, and Anaheim pepper approximately 16 SHU. These results are consistent with previously reported data, indicating that HPLC quantification can provide an objective spiciness index, replacing sensory evaluation.
This study is the first to systematically compare the capsaicin content of seven commercial chili pepper varieties under uniform extraction conditions, establishing a spiciness ranking based on dry weight and demonstrating that dry extraction (drying at 60℃) is 5–11 times more efficient than wet extraction. This research provides important reference data for optimizing industrial capsaicin extraction processes, standardizing spiciness evaluation, and breeding chili pepper varieties.
