Bioactive and nutritional compounds in fruits of pepper (Capsicum annuum L.) landraces conserved among indigenous communities from Mexico

Abstract

Farmers' varieties or landraces of chili are regularly heterogeneous, selected and preserved by small traditional farmers and highly demanded by regional consumers. The objective of this study was to evaluate the variation in the content of phenolic compounds, vitamin C, carotenoids, capsaicinoids and antioxidant activity in fruits of a population collection of the landraces Huacle and De Agua, which originated in Oaxaca, Mexico, and a commercial variety of Jalapeño (control). The collection was grown in greenhouse conditions under a random block design. At harvest, a sample of ripe fruits was obtained to evaluate the content of phenolic compounds, vitamin C and antioxidant activity by UV–visible spectrophotometry and the concentration of capsaicin and dihydrocapsaicin was measured by high-resolution liquid chromatography. Significant differences were observed between the Huacle and De Agua landraces and between these and Jalapeño. The studied fruits exhibit the following pattern for flavonoid and carotenoid contents: Huacle > De Agua > Jalapeño. The opposite pattern was observed for total polyphenol and vitamin C contents: Jalapeño > De Agua > Huacle. The general pattern for capsaicinoids in fruits was Jalapeño > De Agua > Huacle. Huacle and De Agua populations showed high variability in all compounds evaluated, with positive correlations with antioxidant activity. The capsaicin content in Huacle populations varied ranging from 7.4 to 26.2 mg 100 g-1 and De Agua ranged from 12.4 to 46.8 mg 100 g-1.