2018 ASHS Annual Conference

Chili peppers are fruits of genus Capsicum plants of which are grown worldwide. They are goods sources of bioactive phytochemicals, such as phenolic compounds and capsaicinoids, whose health protective effects are well-known. Capsaicinoids are the major bioactive phytochemicals in chili peppers, responsible for their hotness. Concentrations of bioactive phytochemicals in plants depend on genetic (cultivar and maturity) and environmental (climate) factors. In addition, their concentrations differ among parts of the fruit. This study compared phenolic and capsaicinoid concentrations and antioxidant capacities in different cultivars of chili peppers at different maturity stage. They were also compared in different parts (seed, placenta, and flesh) of the chili peppers. These cultivars were grown in the temperate climate of the U.S. Delmarva Peninsula. Six chili pepper cultivars (Scotch Bonnett (SB), Habanero Red and Orange (HR and HO, respectively), Hot Lantern (HL), Numex Suave (NS), Bangkok F1 (BF), and Sahuaro (S)) were grown in the field in the University of Maryland Eastern Shore Experiment Station in 2015. They were harvested at green and ripe mature stages. Immediately after harvest, seeds, placenta, and flesh were separated. Subsequently, the whole pepper and separated parts were freeze-dried, and stored at -18 °C freezer until analysis. Concentrations of phenolic compounds (as total phenolic and flavonoid contents) and capsaicinoids and antioxidant capacities (as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and oxygen radical absorbance capacity) were determined using 80% ethanol extracts from the dried samples. Data were analyzed using analysis of variance and means were compared using the Student-Newman-Keuls multiple comparison method (p<0.05). At the green maturity stage, the phenolic concentrations and antioxidant capacities were likely higher in HO, SB, and BF than in HL, NS, and S, and the concentrations of total capsaicinoids (capsaicin + dihydroxycapsaicin) varied among the cultivars as follows: HO=SB>HR>HL=BF>S=NS (p<0.05). As they became matured, the phenolic concentrations and antioxidant capacities in HL significantly increased (p<0.05) and those in BF significantly decreased (p<0.05). In addition, the capsaicinoid concentrations in HR and BF significantly decreased (p<0.05). No change was observed in other cultivars during maturation. Consequently, at the ripe maturity, the phenolic concentrations and antioxidant capacities were greatly higher in HO and SB than in NS and S, and the concentrations of total capsaicinoids varied among the cultivars as follows: HO=SB>HR=HL=BF>S=NS (p<0.05). The results indicated that HO and SB grown in the Delmarva Peninsula could be good sources of bioactive phenolic compounds and capsaicinoids at any maturity stage.