Development of colour in red pepper fruits in soilless culture

Abstract

SummaryThis study investigated the development of colour and the final quality and minimum maturity for the satisfactory ripening of red pepper (Capsicum annuum L.) fruits (`Americano' and `Fibola' cultivars) on sand and perlite substrates. The extractable colour was evaluated by determining chlorophyll and carotenoid content. The use of the chromatic attributes L*, a* and b* of the tristimulus colour (CIELAB) made it possible to follow the development of reflected colour which takes place during fruit ripening. The mature fruit of `Fibola' turn from green to red more quickly and contain higher levels of carotenoids than those of `Americano'. The a* coordinate, chroma (C*) and the metric saturation (S*) values for `Americano' were higher with sand than perlite substrates, and the contrary was true with `Fibola'. Measurements of surface colour for red paprika pepper fruits were judged to be satisfactory for determining threshold maturity; i.e. minimum maturity for satisfactory ripening when considered 65 d after fruit set for `Fibola' and 70 d for `Americano'.