Characterization of Pepper Genotypes from Serbia as a Function of Maturity by Antioxidant Activity with Chemometric Analysis

The antioxidant activities and total phenolic concentrations of nine pepper genotypes from Serbia in various maturity stages were evaluated using 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), total reducing power, ferric ion-reducing antioxidant power, and cupric ion-reducing antioxidant capacity assays. The effect of maturation on the antioxidant activity of these pepper genotypes had not been evaluated to date. Generally, ripening increases antioxidant activity and total phenolic concentration in all genotypes except for Kameleon. Kameleon peppers exhibited higher total phenolic concentrations and antioxidant activity when immature. From the nutritional point of view, red peppers are the most suitable because they provided higher antioxidant activity values than green and yellow peppers. Statistical analysis showed strong correlation between cupric ion-reducing antioxidant capacity and other assays, so if rapid assessment of antioxidant activity is needed, the cupric ion-reducing antioxidant capacity is the method of choice. Two statistically significant clusters were obtained using chemometric analysis, grouping the mature peppers into the first and immature peppers into the second, as evidenced by principal component analysis. Principal component analysis allowed the classification of the mature and immature peppers.