Capsaicinoid Concentration of Hawaii-Grown Hot Peppers (Capsicum sp.)

Hot peppers have a long history in Hawaii and have potential as a high-value specialty crop for Hawaii growers. Capsaicin and related compounds are the primary determinants of pungency, an important attribute that influences end-use and consumer preference of the crop. However, virtually nothing has been reported on the pungent principles of Hawaii-grown peppers. To better understand the variability of these compounds among commercially available hot pepper germplasm, capsaicinoid concentrations were measured in 15 cultivars of three pepper species (Capsicum annuum, C. frutescens (tentative) and C. chinense) grown in replicated field trials at two locations (O’ahu and Molokai) July-October, 2009. Market mature peppers were harvested, dried, ground and shipped to the Vegetable and Fruit Improvement Center, Texas A&M University. Total capsaicinoids were extracted in 100% methanol, then injected into an HPLC with a liquid phase of 45% acetonitrile, 0.5% phosphoric acid and distilled water. Capsaicinoids were separated on a NovaPak C-18 column. Variability in capsaicinoid concentrations across species was large, and ranged from 39 ug∙g^-1 to 21,395 ug∙g^-1 on a dry weight basis. The highest capsaicinoid concentrations were observed in a Habanero, ‘Red Caribbean’ (C. chinense).  Fruits of cultivars ‘Hawaiian’ and ‘Firecracker,’ tentatively identified as C. frutescens, contained 13,077 and 9,197 ug∙g^-1 capsaicinoids, respectively. Although similar in appearance to C. frutescens fruits, small fruited peppers of C. annuum were lower in capsaicinoids, averaging 2,339 ug∙g^-1. Exploiting the considerable genotypic variability among hot pepper genotypes for capsaicinoid concentrations is suggested as a strategy to improve marketing and value-addition of this crop.