Concentration of Capsaicin and Dihydrocapsaicin in USDA National Pepper Germplasm Collection

A survey was conducted to screen 90 hot pepper accessions selected from the USDA germplasm collection for their major capsaicinoids content. Fresh fruits of Capsicum chinense, C. frutescens, C. baccatum, C. annuum, and C. pubescens were extracted with methanol, and analyzed for capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), dihydrocapsaicin (8-methyl-Nvanillylnonanamide), and nordihydrocapsaicin. Mass spectrometry of the fruit crude extracts indicated that the molecular ions at m/z 305, m/z 307, and 293 which correspond to capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, respectively have a common benzyl cation fragment at m/z 137 that could be used for monitoring capsaicinoids in hot pepper extracts. Capsaicin and dihydrocapsaicin were the dominant capsaicinoids detected in Capsicum species. Capsaicin was higher than dihydrocapsaicin and total content of capsaicinoids varied between species and accessions of the same species from none detectable to 11.2 mg/fresh fruit. Accession PI-441624 (C. chinense) had the greatest capsaicin content (2.9 mg/ g fresh fruit) and accession PI-497984 (C. frutescens) had the greatest dihydrocapsaicin content (2.3 mg/g fresh fruit), while PI-439522 and PI-497984 (C. frutescens) contained the highest concentration of total capsaicinoids. Variability for these traits might be utilized via USDA plant breeding approaches to produce fruits desirable to the consumer for their value-added health-promoting characteristics