Capsaicinoids

A rapid and efficient ultra-high-performance liquid chromatography method with fluorescence detection (UPLC-FLR) was developed for the simultaneous quantification of five major capsaicinoids in chili peppers. Chromatographic separation of nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin II, and homodihydrocapsaicin I was achieved within 5 minutes using a Waters ACQUITY UPLC HSS T3 column (2.1 × 100 mm, 1.8 μm). The chromatographic conditions and the QuEChERS-based sample preparation procedure were systematically optimized. The method validation demonstrated good linearity for each compound within their respective concentration ranges (correlation coefficient r ≥ 0.9902). The limits of detection (LOD) and quantification (LOQ) ranged from 0.10 to 0.28 mg/kg and 0.35 to 0.92 mg/kg, respectively. The average recoveries of the five capsaicinoids spiked in samples ranged from 64.5% to 120.0%, with relative standard deviations (RSD) below 10%. The developed method was successfully applied to analyze nine chili samples from seven varieties cultivated in the Zunyi region. The total capsaicinoid content in these samples ranged from 11.05 to 4532.50 mg/kg (dry weight), revealing significant differences among varieties and the influence of geographical origin. This method is suitable for the rapid and accurate analysis of multiple capsaicinoids in chili peppers and related products.