Ascorbic Acid and Provitamin A Contents in Unusually Colored Bell Peppers (Capsicum annuumL.)

Most bell pepper fruits are green at the unripe stages, and they become red as they ripen. However, the fruits of new varieties may be white, yellow, orange, red, purple, brown, or black. Ascorbic acid, provitamin A carotenoids, proximate composition, and 11 mineral elements were evaluated in these unusually colored bell peppers (Capsicum annuum L.). Over a 2-year period, peppers were grown at the same location following current recommendations for bell pepper production. The fruits were harvested at the unripe and fully colored stages. For each variety, total ascorbic acid and provitamin A contents were determined on two independent samples by microfluorometry and HPLC, respectively. Minerals and proximate composition were determined by AOAC methods. Ascorbic acid (P< 0.001), provitamin A (P< 0.001), protein (P< 0.001), and some minerals (P< 0.001) were affected by genotypes and color stages (R2= 0.96), but fat or moisture was not (P> 0.05). Ascorbic acid increased as color developed in some cultivars, but remained unchanged or decreased in others. Black, purple, and white peppers contained lower ascorbic acid levels compared to the green, yellow, red, brown, or orange peppers. Provitamin A increased as color developed in most cultivars except for yellow varieties. Brown peppers had the highest provitamin A activity compared to other colored peppers.