Variability of Nutritional, Antioxidant, and Textural Traits of a Collection of Snap Beans of Different Colors

Abstract

A set of 54 snap bean lines grown under organic farming was characterized for different traits: pod color, pod cross-section shape, pod section width (PSW), protein content (PC), and sugar content (S). After cooking, the lines were analyzed for firmness and color parameters (CIE-L*, a*, b*). The snap bean lines were grouped based on pod cross-section shape and pod color into eight groups, and significant differences were observed among lines and groups for all the traits investigated. In particular, the yellow pods were harder than the other snap beans and less sweet due to the negative correlation between firmness and sugar content. Fourteen selected lines with contrasting firmness and belonging to different color groups were investigated for their phenolic composition and antioxidant activity (TEAC) before and after domestic cooking. A general decrease was observed only for vanillic acid, quercetin, and apigenin-8-C-glucoside. Quercetin-3-O-rutinoside and kaempferol-3-O-rutinoside were detected in all samples with the highest values in the SBP042 line in both raw and cooked samples. Antioxidant activity decreased with cooking (average of 39%), but purple line SBP053 showed the lowest and no significant loss (3.1%). The results reported in this study could be useful to design specific varieties for different markets and purposes.