Colour differences in paprika pepper varieties (Capsicum annuumL) cultivated in a greenhouse and in the open air

Abstract

The quality of six paprika pepper varieties, cultivated in a greenhouse and in the open air, has been studied. There were differences in their paprika colours with regard to the total content of pigments (ASTA unities) and the quotient of the absorbance spectra values for red and yellow pigments (tint). Using colorimetric measurements, directly carried out on the surface of the ripe fruits, the varieties are clearly separated in the CIELAB space colour, depending on their growing conditions. The colorimetric coordinates a * and b * and quotient a * /b * of the ripe fruits, cultivated in greenhouse, allow to predict the total pigments concentration of the resulting paprika. For the cultivations in the open air, the fruit brightness (L * ) and the chromatic quotient 2000 x a * /L * x b * are the parameters which show best the correlation with the total content of the paprika pigments. The fruit colour change, from green to red, coincides in both growing conditions with the moment when the chlorophyll b concentration surpasses the a one.