Antioxidant properties of pepper (Capsicum annuum L.) depending on its cultivar and fruit colouration

Due to its nutritional, health-promoting and taste-related values, new cultivars are introduced every year. The aim of the study was to assess the biological value of Polish and Bulgarian cultivars of pepper grown in moderate climate conditions and collected at different degrees of maturity. Ascorbic acid, carotenoids, polyphenols, chlorophyll a, chlorophyll b, total chlorophyll and antioxidant activity (DPPH) were determined in air-dried fruit. The investigation included five Polish cultivars: Roberta, Marta Polka, Etiuda, Trapez, and Cyklon and five Bulgarian cultivars: Bulgarski Ratung, Sivriya, Kurtovska Kapiya, Delikates, and Dzuliunska Shipka. Its design involved randomised sub-blocks, with three replications comprising nine plants each. The area of a single plot was 1.44 m2 (1.2 m × 1.2 m). The study confirmed the strong antioxidant properties of pepper grown in the field, without cover, and under temperate climate conditions. The vegetable is rich in vitamin C, polyphenols, carotenoids, chlorophyll pigments, and shows high antioxidant activity. However, the biological value of pepper is cultivar-dependent and is also determined by the fruit colouration degree. The coloured fruits are richer in vitamin C and carotenoids than the green ones, and when matured, they have greater antioxidant capacity. Green fruits contain more chlorophyll a, chlorophyll b and total chlorophyll than the coloured ones. The fruits of cv. Etiuda were the richest in vitamin C, of cv. Sivriya in polyphenols, of cv. Dzuliunska Shipka in carotenoids, and of cv. Trapez in total chlorophyll. Cv. Sivriya showed the strongest antioxidant properties.