Determination of Capsaicin in Hot Peppers Jayla Motley, Junior, Christian County High School, Kentucky Ms. Regina Hall, Research Assistant, CAFSSS Mr. Eric Turley, Co-Investigator, CAFSSS
At the present time, 90% of U.S. chili pepper production occurs in New Mexico, eastern Arizona, and western Texas. Pungent hot pepper varieties are grown for their food value, health-promoting properties and also as a source of capsaicinoids (which have a variety of medicinal uses). The objectives of the investigation were: 1) to quantify the major capsaicinoids (capsaicin and dihydrocapsaicin) in hot pepper fruits accessions and 2) to identify accessions containing greatest concentrations of capsaicinoids. Hot pepper seeds were grown under four soil management practices (sewage sludge, chicken manure, yard waste, and no-mulch (control) treatment) to monitor and quantify capsaicin and dihydrocapsaicin content in pepper fruits. Ninety Capsicum accessions selected from the USDA Capsicum germplasm collection were screened for their capsaicinoids content using gas chromatography (GC/NPD). Fresh fruits of Capsicum chinense, C. frutescens, C. baccatum, C. annuum, and C. pubescens were extracted with methanol, and analyzed for capsaicin, dihydrocapsaicin and nordihydrocapsaicin content. Mass spectrometry of the fruit crude extracts indicated that the molecular ions at m/z 305, 307, and 293 which correspond to capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, respectively, have a common benzyl cation fragment at m/z 137 that can be used for monitoring capsaicinoids in hot pepper fruit extracts. Quantification of capsaicinoids in the selected accessions allowed us to identify genotypes with high levels of total capsaicinoids and enabled the prediction of the amount of each component that can be obtained per kg and per acre of hot peppers produced.