Quantitative profiling of capsaicin content in seven chili pepper cultivars using optimized HPLC

Capsaicin is the primary active compound responsible for the pungency of hot chilies (Capsicum spp.), functioning both as a deterrent to predators and as the trigger for the burning sensation produced by the activation of sensory neurons. It is also widely used in food and is associated with multiple health benefits for humans. This research focuses on quantifying and comparing capsaicin levels in various chili peppers to address the limited quantitative understanding of their pungency. The main objective was to determine capsaicin content across seven chili pepper cultivars (Habanero, Thai chili, Serrano, Jalapeño, Shishito, Poblano, and Anaheim) to better understand variations in spiciness. Using high-performance liquid chromatography (HPLC), the peppers were ranked from hottest to mildest based on capsaicin content. Results showed that Habanero had the highest capsaicin content (4,777 ± 588 mg/kg dry weight), while Anaheim had the lowest (0.9 ± 0.04 mg/kg dry weight). The overall ranking from hottest to mildest was: Habanero > Thai chili > Serrano > Jalapeño > Shishito > Poblano > Anaheim. Capsaicin levels in Habanero were considerably higher than in other varieties-158% higher than Thai chili, 357% higher than Serrano, and approximately 29,000% higher than Jalapeño. For quantitative determination of capsaicin, we used reversed-phase HPLC with UV-Vis detection. Notably, dry-pepper extractions yielded 542%-1,110% more capsaicin than wet-pepper extractions. This finding highlights the significant impact of drying on capsaicin extraction efficiency. Comparative analysis showed that hot chili varieties such as Thai chili, Habanero, and Serrano have very high capsaicin levels compared to Jalapeño, Shishito, Poblano, and Anaheim. HPLC-based quantification offers an objective and reproducible alternative to the Scoville Heat Units (SHU) scale for assessing the pungency of peppers. The findings of this study enhance understanding of capsaicin extraction and provide additional information into characterizing pepper spiciness, helping farmers, researchers, and the public gain deeper insights into the factors that determine pepper pungency.