Characterization for bioactive compounds of Spanish pepper landraces

Abstract

After the discovery of America, Spain was the point of entrance to the Old World for several vegetables native to America, including chilli peppers (Capsicum spp.). Such diversity of introduced peppers evolved, after hundreds of cycles of selection under specific conditions, to a plethora of landraces, in particular of Capsicum annuum L. As a consequence, Spain became an important centre of diversity for this crop. At the nutritional level, Capsicum peppers are known for their antioxidant bioactive compounds. However, systematic studies of the variation for these compounds among Spanish landraces have not been undertaken. As part of our pepper breeding program, we present the results of our studies on the ascorbic acid content (AAC) and total phenolics (TPs) of eight important Spanish pepper landraces. Several foreign landraces were included as external controls. Given that Capsicum peppers can be utilized at both mature (fully ripe) and green (unripe) stages, all landraces have been analyzed at both stages. A wide range of variation was found for both AAC and TPs at both ripening stages. Thus, AAC ranged between 371 and 2480 mg/kg (on a fresh weight basis) in green fruits and between 1083 and 3690 mg/kg in fully ripe fruits. Most cultivars showed a higher AAC in the mature stage than in the green stage (on average 60% higher, but up to 10-fold higher in some cases). TPs content ranged between 367 and 2383 mg/kg in green fruits and between 658 and 4319 mg/kg in ripe fruits. Although, on average, ripe fruits had 59% higher TPs content than green fruits, several landraces showed higher TPs content when unripe. This work has allowed us to identify those landraces with a higher content of nutritionally bioactive compounds, as well as selecting sources of variation for breeding programs aimed at improving the nutritional value of peppers.